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·NUTRITIONAL DIAGNOSIS

·Publication Number 356
AMERICAN LECTURE SERIES
A Monograph in
AMERICAN LECTURES IN METABOLISM
Edited by
SO WAIFE MD
The Lilly Research Laboratories
Indianapolis Indiana
and
PAUL GYÖRGY MD., CONSULTING EDITOR
Professor of Pediatrics
University of Pennsylvania School of Medicine
Philadelphia, Pennsylvania

·NUTRITIONAL
DIAGNOSIS
Ву
GRACE A. GOLDSMITH, B.S, MD,
M.S (Med ), F.A.CP
Professor of Medicine and Director Nutrition Metabolism Unit, Depart
ment of Medicine, Tulane University School of Medicine
Consultant Physician, Charlty Flospital of Louisiana at New Orleans
CHARLES C THOMAS
Springfield Illinois
PUBLISHER
• U.S.A

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·Dedicated
to my good friend
Sue Cannon Price

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·FOREWORD A PROGRAM of nutrition research was initiated by the author more than fifteen years ago in the Department of Medicine at Tulanc Univcrsity In its incipicncy, research dealt largely with the B group of vitamins in human nutrition As the program expanded, investigation of protcin, carbohydrate, lipid, mineral and vitamin metabolism has been included Basic biochemical rescarch and studics in cxperimental animals as well as in man have becn integral parts of the program A special clinic for nutntional diagnosis and therapy was established in the Hutchinson Memorial Clinic at Tulane and nutntional consultation services were initiated at Charity Hospital of Louisiana at New Orleans In addition, the program has included teaching of clinical and biochemical aspects of nutrition to undergraduate medical students and to post graduate students in both biochemistry and medicine Much of the material included in this revicw stems directly or indirectly from knowledge and experience gained through development of this nutrition program The purpose of this monograph was to gather together and evaluate current information on nutritional diagnosis Need for a résumé in this field has been apparent for some time It is hoped that such a summary will prove useful to the practicing physician in evaluating the nutritional problems of his patients, that it will generate interest in the field of nutritional diagnosis and that it will stimulate investigation which may lead to more precise diagnosis in the future vit ·Collection and choice of material for inclusion in this review has been a formidable task There are so many facets that it is difficult to cover the entire nutrition spectrum adequately in a reasonable amount of space In view of the extensive literature, it has not been possible to give individual credit to everyone who has made significant contributions, desirable as it would be to do so In the bibliography, reference has been made to reviews and symposia whenever possible, rather than to reports of individual research Findings which are generally accepted have not been annotated, while recent reports and new methods of diagnosis have received specific citation in most instances Publication of this book provides a welcome oppor tunity to gratefully acknowledge the assistance of many persons, foundations and agencies Our nutrition pro gram could not have reached its present status without the continued interest and financial support of the Nutrition Foundation, the Williams Waterman Fund of the Research Corporation and the Division of Research Grants and Fellowships of the Public Health Service The author is most grateful for the assistance and co operation of many distinguished colleagues The late Dr John Herr Musser, who was Professor of Medicine at Tulane University for many years stimulated my original interest in nutritional problems This interest was en couraged by Dr Russell Wilder under whom I was privileged to study at the Mayo Clinic The assistance and wise counsel of Dr C Glen King and Dr Robert R Wil liams over a number of years have been of inestimable value The opportunity of working with members of the Food and Nutrition Board of the National Research Coun cil and of the Council on Foods and Nutrition of the vui ·American Mcdical Association has been most stimulating and is deeply appreciated I am indebted, also, to the past and present members of thc Nutrition Rescarch Group at Tulanc University who has worked with me in the clinics, hospital wards and laboratorics Thc help of my capablc sccretary is also gratefully acknowledged This book was written largely during summer vacations and I am indebted above all to my good friend Suc Cannon Price for her cncouragcment and understanding and for sharing the difficulties and frustrations inherent in preparation of this monograph GAG x

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·CONTENTS Forcword ... I INTRODUCTION 3 II GENERAL OBSERVATIONS Medical History Dictary History Physical Examination Growth of Infants and Children 7 8 10 15 20 ve .. - PRO... POE .. Doce 29.... deve III CALORIC NUTRITION Methods for Evaluation Calorc O.cmutrition Calonc Undernutrition 28 28 29 30 IV PROTEIN NUTRITION Protein Requirement and Dietary Evaluation Protein Deficiency Specific Amino Acid Deficiencies Protein Nutrition and Cırthosis of the Liver The Kwashiorkor Syndrome - Protein Needs for Repletion 34 34 38 43 45 48 V CARBOHYDRATE NUTRITION 49 VI LIPID NUTRITION Serum Lipid Concentrations Absorption of Lipids Ketosis Lipids and Liver Disease Lipids and Gallbladder Disease 53 54 58 81 61 62 ·VII MINERAL NUTRITION Water and Electrolytes Water Depletion Water Intoxication Sodium and Chloride Sodium Depletion and Retention Combined Water and Salt Depletion Hypernatremia Potassium Potassium Deficiency Hyperkalemia Calcium Calcium Deficiency Phosphorus Magnesium Sulfur Iron Iron Deficiency Iron Excess Copper Cobalt Iodine Iodine Deficiency 63 63 65 66 68 70 73 74 74 76 79 79 81 82 83 84 85 87 90 90 91 91 92 VIII VITAMIN NUTRITION General Observations Vitamin A Vitamin A Deficiency Hypervitaminosis A Vitamin B Complex Thiamine Thiamine Deficiency Riboflavin Riboflavin Deficiency Niacin Niacin Deficiency 94 94 96 98 100 101 103 103 108 109 111 113 .

·av. Vitamin B. Vitamin B, Dcficiency Pantothenic Acid Folic Acid Folic Acid Dcficicncy Vitamin B. Vitamin B,, Deficiency Cholinc Biotin Inositol Ascorbic Acid Ascorbic Acid Dcficiency Vitamin D Vitamin D Deficiency Vitamin E Vitamin Vitamin K Deficiency IX NUTRITIONAL DIAGNOSIS-TIE FUTURE .. 110 110 110 101 122 120 128 132 13-1 131 134 130 140 142 140 147 148 150 References 152

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·NUTRITIONAL DIAGNOSIS

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·INTRODUCTION Nurmonal diagnosis is an integral part of cu cry medical evaluation cicn when attention is directed primanly to some other phase of n patients problem and nutritional therapy is an essential ſciturc in thic management of ci cry discasc stalc although it may involc only institution or maintenance of an adequatc dict Unfortunately, the nutritional state of a paucnt is often talon for granted or dismissed with a cursory observation of the abundance or scarcity of bodily fat A notc may be made in the record "well de cloped and well nourished" and investigation is pursued in other directions In general, medical practice has not kept abreast of the tremendous advances in nutritional science and the refinements in nutritional diagnosis which have been cvoked in recent years It is true that the health hazards of obesity are receiving considerable emphasis and the importance of electrolyte balance is recognized with increasing frequency Nevertheless, these are only facets, although important ones, in the broad field of nutrition Vitamins have been prescribed for a wide variety of major and minor complaints, often without reason or justifiable hope of efficacy Each new vitamın has been heralded as a panacea for many of the unsolved problems of medicine Such unscientific enthusiasm has resulted in unwarranted scepticism on the part of many physicians as to the importance of vitamins and of other nutntional factors as well, in the pathogenesis and therapy of disease The term nutrition is often considered in a narrow 3 ·NUTRITIONAL DIAGNOSIS sense as meaning knowledge of the essential chemical substances which must be included in the diet and application of this knowledge to dietotherapy The science of nutrition embraces a much wider field Knowledge of the role of essential nutrients in metabolism, which in cludes the whole realm of nutritional biochemistry, is vital in the understanding of normal bodily function and the many disturbances which occur in disease Many types of disease, whether infectious, metabolic or degenerative, influence the nutritional state of the patient and in turn, nutrition influences the prevention, develop ment and regression of many pathologic states Nutritional diagnosis means much more than the de tection of some overt deficiency disease, a concept prevalent some years ago Today, it is essential to think less in terms of specific deficiency states and more in terms of disturbances in the biochemical reactions of the body The diet must furnish the potential energy for basal meta bolic processes and for physical activity and, also, all of the chemical substances needed for manufacture of new tissue Recent investigations, using isotopic techniques, have indicated that the components of cells are constantly being broken down and reconstituted, requiring continuous replenishment with essential nutrients (1) Nutrı tional diagnosis implies, therefore, evaluation of the bio chemical milieu within and outside of the cells, as well as detection of abnormalities of function and structure of the organs and tissues of the body Recent studies of the role of mitochondria and other cellular units in oxidative metabolism link cytology and biochemistry closely to gether and may lead to better correlation between pathologic anatomical changes and biochemical abnormalities of body tissues and fluids In general, nutritional deficiency occurs gradually al- ·INTRODUCTION 5 though the speed of de clopment varics widely The resenc storcs of nutrients arc depleted before biochemical or physiological dysfunction des clops Gross structural changes in tissucs arc usually latc manifestations of scvcrc or prolonged dcplction Attunment and maintenance of ndcquatc nutrition is not difficult in the United States, since a wide variety of food is readily availablc Consequently, the importance of nutrition may not be appreciated sufficiently in this country, except in situations of cutreme poverty and neglcct or in sci crc illness In many countries of the world, scrious degrees of malnutrition arc common and it is in these areas that the vital role of nutrition in health is demonstrated most strikingly The importance of nutrition in growth and development, and in the maintenance of physical, mental and emotional well being throughout life, is attested by natural csperiments in endemic areas of poor nutrition as well as by planned laboratory experiments with human volunteers Alinot s statement (2) that the history of the world might be written in terms of nutrition rather than in terms of epidemics, as in Hans Zinsser's book Rats, Licc and History, does not seem to be an exaggeration The importance of nutrition in conditions of physio logic stress ie, in growth, pregnancy and lactation, has been well documented Recent investigation indicates a close relationship between nutrition and many forms of pathologic stress such as severe infections or trauma Relationships between nutrition and some of the degen erative diseases, for example atherosclerosis and hypertension, and even between nutrition and neoplasia have been demonstrated It is in this wide vanety of pathologic states that nutritional diagnosis assumes paramount importance in well fed population groups In rehabilitation ·4 NUTRITIONAL DIAGNOSIS sense as meaning knowledge of the essential chemical substances which must be included in the diet and applı cation of this knowledge to dietotherapy The science of nutrition embraces a much wider field Knowledge of the role of essential nutrients in metabolism, which in cludes the whole realm of nutritional biochemistry, is vital in the understanding of normal bodily function and the many disturbances which occur in disease Many types of disease, whether infectious, metabolic or degenerative, influence the nutritional state of the patient and, in turn, nutrition influences the prevention, development and regression of many pathologic states Nutritional diagnosis means much more than the de tection of some overt deficiency disease, a concept prevalent some years ago Today, it is essential to think less in terms of specific deficiency states and more in terms of disturbances in the biochemical reactions of the body The diet must furnish the potential energy for basal metabolic processes and for physical activity and, also, all of the chemical substances needed for manufacture of new tissue Recent investigations, using isotopic techniques, have indicated that the components of cells are constantly being broken down and reconstituted, requiring contin uous replenishment with essential nutrients (1) Nutrı tional diagnosis implies therefore evaluation of the biochemical milieu within and outside of the cells, as well as detection of abnormalities of function and structure of the organs and tissues of the body Recent studies of the role of mitochondna and other cellular units in oxidative metabolism link cytology and biochemistry closely to gether and may lead to better correlation between pathologic anatomical changes and biochemical abnormalities of body tissues and fluids In general, nutritional deficiency occurs gradually al ·GENERAL OBSERVATIONS Numurova diagnosis is not easy in spite of the mass of information accumulated in recent decades Varation among individuals is great and the dividing linc between normal and abnormal is not clear-cut This might bc anticipated since nutritional attributes and functions would be crpccted to show normal destnbution cun es as do other physiologic vanables Nor should this be discouraging since similar difficulties are found in all fields of biological investigation and similar problems are cncountered in the diagnosis of cardiac, pulmonary or gas trointestinal descasc Basic scientific knowledge couplcd with astute clinical observation forms the foundation of diagnostic acumen Adeptness in the art of obtaining a medical history, Acenness in detecting minor physical deviations from the normal judicious choice of laboratory procedures, and ability to correlate all findings into a comprehensive wholc, are the “sine qua non” for nutritional diagnosis as for diagnosis in other fields of medicine It is essential to know nutritional requirements and the function of nutrients in health and to be cognizant of the potential influence of disease on the requirement and utilization of nutrients Know ledge of the effects of an inadequate supply of essential dietary factors is a requisite for accurate diagnosis Cultivation of nutntion consciousness” and an awareness of the nutritional aspects of biochemistry and metabolism is almost obligatory 7 ·6 NUTRITIONAL DIAGNOSIS from all types of injury, close attention to nutritional problems reaps a rich reward decreasing morbidity and mortality The frequency with which nutritional defects are en countered is not appreciated by many physicians A casual walk through the wards or private rooms of any large hospital will attest the high incidence of nutritional problems Malnutrition is usually obvious in the patient with cirrho sis of the liver, advanced pulmonary tuberculosis or chronic ulcerative colitis It is recognized readily that maintenance of adequate nutrition is difficult during the recovery period after total gastrectomy or resection of the colon It is perhaps less obvious that nutritional problems are common and of significant import in the patient with congestive heart failure rheumatıc fever, peptic ulcer or some type of allergic state Similar examples could be cited in all branches of medicine In view of the frequency and importance of nutritional problems in medical practice, a review of the methods and procedures currently available for nutritional diagnosis and of criteria useful in the evaluation of nutritional status seems warranted Nutritional diagnosis is not so exact that abnormalities of cellular chemistry can be detected with precision Much remains to be learned and new tools and methods must be developed Nevertheless progress has been rapid The present state of knowledge and areas requiring future development will be summarized in the sections that follow ·GENERAL OBSERVATIONS 9 These must be sought by adroit questioning and confirmed or discarded by physical crimination and approprate laboratory procedures Findings in childhood u lich suggest nutritional de ficiency include failure to grow or gain weight, poor appetite, Icthargy, dısıntcrest in play and irritability In adults, some of the common complaints which may be associated with malnutntion arc cas; fatigability, loss of weight and strength and anorexia Symptoms may indicate dysfunction of any of the bodily systems Photophobia, buming of the eyes, lacsimation and night blindness may be observed Soreness of the lips, tongue and angles of the mouth, digestive disturbances and diarrhca are not infrequent. Palpitation, dyspnea and edema may be due to nutntional deficiencies Parasthesias and other sensory changes, particularly of the fingers and toes, easy bruising and dryness and pigmentary changes in the skin are often encountered. Since all of the above symptoms may occur in doverse pathologic conditions, all potential causatııe factors must be investigated. The past medical record is valuable in indicating recent recurrent or chronic disease or trauma, which may be related to the findings observed or affect nutritive state Religious and social customs occupation and economic status, in fact, practically all aspects of the ens ironment whether geographical, physical or educational may erert an influence on food habits and on nutrition The family history, too provides informative data. Family size, the record of illnesses and death, the occurrence of stillbirths, may shed light on nutritional problems Fertility and the course of pregnancy are influenced by diet Delayed puberty, amenorrhea and impotence may be due to undernutrition or malnutrion as well as to other causes ·8 NUTRITIONAL DIAGNOSIS MEDICAL HISTORY The medical history is of great importance in detecting the presence of disease which may influence nutritional status and in eliciting symptoms which suggest nutritional abnormality The physician should be aware of the phys 1ologic, pathologic, or therapeutic situations which are prone to induce nutritional deficiency or excess Nutritive requirements may be increased in many dis eases, particularly those in which basal metabolic rate is increased such as febrile illnesses, hyperthyroidism and certain other endocrinopathies, leukemia and polycythemia and diseases of the heart and lungs associated with severe dyspnea In a number of psychotic states, abnormal physical activity increases total metabolic needs Many diseases and some therapeutic agents interfere with ingestion, digestion or absorption of food Diseases of the gastrointestinal tract and the myriad conditions associated with anorexia, nausea, vomiting and diarrhea belong in this category Interference with the utilization of nu trients may be observed in hepatic disease, hypothyroidism, advanced renal disease, neoplasia, and following radiation therapy Severe injuries, shock, and chronic anemic states profoundly affect metabolic processes Nu trients may be lost from the body in conditions associated with polyuria, in therapeutic diuresis, and following ad ministration of certain drugs Nutntional excess is best exemplified by an overabundance of calories but metabolic disturbances and therapeutic agents may lead to syndromes in which er cessive amounts of nutrients particularly certain minerals and vitamins accumulate in the tissues The physician must know the symptoms and signs asso ciated with an inadequate or overabundant supply of each of the chemical substances essential in human nutrition ·GENERAL OBSTRVATIONS TABLE 1 D-ITAY RECORD Name TIeight Welcht Diel-Presious 24 hours Breakfast Noon Meal Evening Meal Beraton Meals Food Amt. Food Amt Food Amt Food Amt Diet llistory-Foods used- Amount and frequency (day, week or month) Meat Fresh (beef seal lamb pork) Fish Fon1 Llier Prepared salt Breads Bread (kind) Biscuit Corn bread Crackers Eggs Muk Whole, skim, evaporated butter milk Cereals Rice Grits Macaroni spaghetti Cooked Prepared Cheese Sweets Syrup molasses Jams, jelly Candy Desserts Nuts and Pearut Butter Fats Butter oleomargarine Mayonnaise Cream Vegetables Legumes, dried Legumes fresh Green Yellow Potatoes, Irish Potatoes Sweet Tomatoes Other vegetables Fruits Citrus Others, canned Others fresh Juices Beverages Coffee Tea Soft drinks Alcohol Other food Food dislikes Number of meals eaten per day Vitamin preparations ·10 NUTRITIONAL DIAGNOSIS DIETARY HISTORY The dietary record is an important part of the medical history Although a quantitative estimate of recent and habitual food intake may be difficult to obtain, it is usually possible to glean sufficient information to evaluate the diet from a qualitative standpoint Several methods of obtaining dietary information have proved useful A simple procedure is to ask the patient to recall the kinds and approximate amount of foods eaten in the previous 24 hours and to ascertain whether or not this is represen tative of the usual dietary pattern The accuracy of the 24 hour diet record may be checked by the use of a list of common foods (divided into several principal groups), the patient being asked to indicate how often each is included in the diet (Table 1) Another method of ob taining dietary information is to have the patient keep a record of all food eaten, including amounts, for a period of several days to a week These records are then evaluated by comparison with some dietary standard Difficulties in eliciting accurate dietary information are numerous Many persons do not remember what they eat and have a poor idea of quantity, some tend to exaggerate, while others underestimate Patients may be ashamed of the meagerness of their diets and conceal this information, others may describe their food intake in terms of what they believe the physician considers desirable In spite of these and other pitfalls the dietary record often suggests deficits which can be investigated further by clinical or laboratory tests Evaluation of the diet from a qualitative standpoint can be carried out easily by the physician in his office by using some simple standard such as that shown in Table 2 This was devised for appraisal of the diet of an adult in the United States Similar tables can be prepared which are ·GENERAL OBSERVATIONS 13 applicablc to children or to other countries If it is dc. sirablc to obtain morc dctailed information as to the quanlity of specific nutrients in thic dici, inblcs of food composition arc available which permit such calcula uon (3) Many dictary standards huic lccn formulated by national and international groups (1) The purpose of thcsc standards and thic philosophics on which thcy arc bascd hasc varied widely in the United States, thc Rccommended Dictary Allowances of the food and Nutrition Board of the National Research Council (1a)) has been uscd extensively (Table 3) Thicsc allow anccs represent the amounts of cssential nutritic substances which ap pcar desirable for the maintenance good nutrition in essentially all hсalthy persons in the United States Thicy are more than minimum requirements and represent goals toward which to strive in planning dicts and food sup. plies If these allow ances arc used in quantitative cvaluation of the diet of an individual, they must be interpreted correctly A person whose diet meets recommended allowances will rarely exhibit nutritional deficiency, ercept in the presence of some discase which influences require ment or utilization of nutrients On the other hand, if a person s diet fails to fulfill recommended allowances, this does not necessarily signify nutritional deficiency A nu trent intake considerably below recommended allowances suggests inadequatc intake and requires additional investigation Dietary cvaluation has been used extensively as one aspect of the appraisal of nutritional status of population groups Dietary surveys are valuable particularly in areas where food supply is limited and have served as a basis for planning nutrition programs Changes in food consumption of population groups can be followed with this ·12 NUTRITIONAL DIAGNOSIS TABLE 2 STANDARD FOR EVALUATION OF DETARY PATTERN IN ADULT SUBJECTS Food Group Amount Recommended Daily Primary Purpose Two or more servings (1 cup or 8 oz each) 1 Milk Cheese and ice cream can replace part of milk Protein Calcium Riboflavin Vitamin A Two or more servings (at least 2 oz each) 2 Meat Beef veal pork, lamb poultry fish eggs. Dry beans and peas and nuts can be used as alternates Protein Thiamine Riboflavin Niacin Iron Four or more servings (1/2 cup each) 3 Vegetables and fruits Should include a) a dark green or deep yellow vegetable at least every other day for vitamin A b) a citrus fruit or other frut or vegetable rich in vitamin C daily c) other fruits and vegetables in cluding potatoes Vitamin A Ascorbic acid Iron Thiamine Riboflavin Niacin Trace minerals 4. Bread and cereals whole grain, en riched or restored Four or more servings (1 slice bread or 12 cup cereal) Thiamine Niacin Iron Protein Riboflavin Calories Vitamin A Other foods sugars, fats oils, includ ing butter or for tified margarine for vitamin A For further details reler to Essentials of an Adequate Diet. Agriculture Information Bulletin No 160 Washington DC Agricultural Research Service, V S Dept. Agriculture, November 1956 ·GLITRAI OBSERVATIONS 15 suncy method Sclection of proper standards with which to judge thic nutritic mluc of dicts is important, stand. dards applicablc in onc community may require modifica tion in another Victhods and procedures Buch may hc useful in dietary suncys are discussed in sci cral recent TCVCWS (5) PIIYSICAL ILAMINATION A thorough and detailed physical crimination cin grc much information relative to nutritional status although laboratory procedures may be nccded to substantiate diagnosis It should be hept in mind that nutritional deficiencies are often inultiple and that similar lesions may be caused by an inadequate supply of more than onc nutrient Furthermore, the type of physical abnormality encountered varics according to the duration and sei crity of the deficiency There are almost no pathognomonic findings, a situation which holds in other diagnostic fields However, a combination of symptoms and signs, together with historical and laboratory data will permit accurate diagnosis in most instances General inspection yields much valuable information, in fact it is often possible to tentatively appraise the whole nutritional problem if observation is sufficiently keen Observation begins when the patient is first seen in the home, office or hospital and while the history is being recorded The physician gains an impression of the patients general health, vigor, intelligence and emotional reactions Gross defects in caloric nutrition are obvious excessive fat pads denote obesity, absence of subcutaneous fat indicate excessive leanness folds of sagging inelastic skin suggest marked loss of weight The stature general skeletal development, bulk of muscle color and texture of skin and hair are noted almost subconsciously Edema ·TABLE 3 FOOD AND NUTRITION BOARD NATIONAL RESEARCH COUNCIL RECOMMENDED DAILY DIETARY ALLOWANCES REVISED 1958 DESIGNED FOR THE MAINTENANCE OF GOOD NUTRITION OF HEALTHY PERSONS IN THE U.S.A. (Allowances are intended for persons normally active in a temperate climate) 14 dor Yed Tagli Height Calories Protein Coletem gmt Iron mg Pamin A Thism IU mo Miho 77-8 Nuacen? mg tau! Volament Anc ded Vitamin D mo I Bica 1 B 3900 3000 550 70 70 70 08 08 08 10 10 10 5000 5000 5000 21 20 18 5 3 15 Women 0 (154) 175 (19) 15 70 (154) 1 175 (69) 65 70 (154) 175 (69) 5 58 (18) 163 (64) 15 58 (128) 163 (64) 055 58 (18) 163 (64) Pregaat (second bain Lactating (850 ml. daily) 5000 15 15 17 5000 2300 200 1800 + 300 +1000 58 58 58 +0 +40 WOW 08 08 08 13 20 1 12 12 15 15 5000 6000 8000 10 1 3 0 70 70 100 150 20 25 ++. 400 400 Infanta 0-1/12 2/12-0/12 7/12-12/12 See Footnote 1500 1500 cro 05 08 on 30 30 400 400 Children 1 3 46 79 10-12 6 (13) 80 (24) kg.x120 9 (20) 70 (28) kg 1100 12 (27) 87 (34) 1300 18 (40) 109 (43) 1700 27 (80) 1 9 (51) 2100 36 9) 144 (57) 500 40 50 60 70 7 8 000 500 3500 4500 07 09 1 -------- WWW.NOOO-a 10 1 3 5 18 8 11 14 17 35 60 60 75 400 400 400 400 NUTRITIONAL DIAGNOSIS 12 Вот 13 15 16-19 3100 3600 85 100 15 15 5000 5000 21 23 49 (108) 163 (84) 63 (139) 175 (89) 49 (108) 160 (63) 54 (190) 102 (84) 90 100 400 400 Gurls 13-15 16-19 600 2400 80 15 5000 5000 20 17 80 80 400 400 (1) The allowance levels are intended to cover ind y dual vanations among most normal persons as they live in the United States under usual envi mental stresses The recommended allowances can be attained with a var ety of common foods providing other nutrients for which human requirements have been less well defined See text for more detailed discussion of allowances and of au trients not tabulated (2) Niacin equivalents laclude dietary sources of the preformed vitamin and the precursor tryptophan 60 milligrams tryptophan equals 1 niacia others in sedentary occupat ona they are excessive Adjustments must be made for variations in body (3) Calorio allowances apply to ind viduals wually engaged in moderate physical actions in past lize parte din catheticity and environmental temperature (4) See text for discussion of Infant allowances The Board reogn es that human milk is the natural food for infants and feels that breast feeding is the best and desired procedure for meeting nutrient requirements in the first months of life No allowances are stated for the inst month ot lue Breast feeding is particularly indicated during the first month when infants show handicaps 10 homeostasis due to d fferent rates of maturation of digestive excretory and endocrine functions Recommendations as listed per tala to nutrient intake as afforded by cow milk formulas and supplementary foods given the intent when breast feeding is termi rated Allowances are not given for prote a during Intancy ·GENERAI OBSERVATIOVS 17 TABLE 4 Purrsical Sons What MAY REASOCIATED Wmt MALNUTAMOY Terth Caries Identulous Dentures Tuorosis Apathetic appearance Hair dry "starings Dyspigmented Skin, fudal Seborrhea, nasolabial Scborthea, other Erythema Folliculosis Skin, general Dryness and saling Crackled skin Hyperpigmentation Depigmentation Follicular keratosis Perifolliculosis Acneiform eruption Thick, pigmenied pressure points Purpura and petechis Bluish red cold extreenities Pellagraform lesions "Crazy pavement" dermatitis Telangiectasis Redness of palms Nails, brittle flaking ridging spoon shaped Eyes Bitot s spots Canthi fissures Circuncorneal injection Conjunctival injection Lids, blepharitis follicular hypertrophy Lips and mouth Angular lesions Angular scars Cheilosis Pallor Ulcers of mouth Tongue Papillary atrophy Papillary hypertrophy Magenta color Red tip and/or sides Fissures Erosions or ulcers Serrations and swelling Gums Marginal rodness Marinal swelling Bloeding Thyroid Enlarged (colloid goiter) Parotid gland bilateral enlargement Neuromuscular Call tenderness Loss of ankle or knee ferks Plantar dysesthesia "Burning ſeet" Motor weakness, paralysis Vibratory sense lost Position sense lost Hypesthesia and anesthesia Tetany Skeletal Posture Frontal or parietal bosses Protuberant abdomen Harrison s groove Knock knces Bowlegs Enlarged wrists Enlarged costochondral Junctions Faring ribs Winged scapula Abnormalities of stemum Cardiovascular Hypotension Bradycardia or tachycardia Cardiac enlargement failure Abnormalities of rhythm Murmurs Edema Liver Enlarged nodular ·16 NUTRITIONAL DIAGNOSIS of marked degree is readily detected The general attı tude and behavior of the patient, alertness or apathy, anxiety or depression, the facial expression, manner of speech and type of voluntary movements, all contribute to solution of the diagnostic problem This is particularly true when severe malnutrition is suspected, in starvation and severe protein deficiency, depression, apathy and lassitude are characteristic findings Differences in physiological and emotional reactions among various racial groups and among individuals must be considered in reaching an evaluation Observation of the spontaneous behavior of children has been found to be most useful in appraising nutritional status Lassitude, lack of interest and absence of spontaneous play are common in mal nutrition In children, too, posture may reflect nutriture a forward slump of the head, kyphosis, lordosis, winged scapula and pot belly, all of which are expressions of poor muscle tone, are observed frequently among those who are poorly nourished Detailed physical examination of all systems of the body should follow general inspection When nutritional diagnosis is applied to population groups, especially in large or rapid nutrition surveys, attention is directed particularly to the superficial tissues, the skin, hair, mucocutaneous junctions, eyes, and buccal mucous membrane Schedules have been prepared for use in such nutritional appraisal (6, 7) Some of the physical findings commonly associated with malnutrition which may be searched for in nutrition surveys are given in Table 4 These abnormal signs and symptoms are also useful in evaluating the nutritional status of the individual patient It is obvious that many of these findings are non specific and that some are more closely related to malnutrition than others The presence of several abnormalities is ·CITAT OBSTRUATIONS 19 TABLE S (Contirund) Vumin D de ciency Scbonheic dermatitis Glossitis Angular somatlils Peripheral neuropa hy Itamin 1 dekoracy Ilohazla menilos atlons in Jeundle or in the nerborn Folic kad dciciency Weln und pallor Gloss: is redness, abnormallilos of papillac Dianhes, stcalonthea Calcium deficiency Tarotholes Corpo-pedal spasm Convulsions Porithe Chronicks and Trous sau s signs Iodine deficiency Simple goltes Vitamin B, deficiency Weakness and pallor Glossius–redness, abnormalities of papillae Subacute cornbined sclerosts Peripheral neuropathy Iron deficiency Weakness and pallor Chronic glossitis hoilonychia Ascorbic acid deficiency Purpura, petechiae, ecchymoses Red, swollen, bleeding gums Perifolliculosis Poor sound healing Magnesium deficiency Gross muscle tremor Delirium Potassium deficiency Muscular weakness, hypotonia Flaccid paralysis Paralytic ileus Cardiac or respiratory failure Vitamin D deficiency Craniotabes Frontal and parietal bosses Enlarged joints (wrists and ankles) Harrisons groove Enlarged costochondral junctions Deformities of sternum Bowlegs or knock knees Osteomalacia Sodium deficiency Weakness, apathy Anorexia, nausea vomiting Muscle cramps Peripheral circulatory collapse ·18 NUTRITIONAL DIAGNOSIS TABLE 5 SYMPTOMS AND SIGNS SUGGESTIVE OF DEFICIENCY OF CERTAIN NUTRIENTS Caloric deficiency Underweight and underheight Weight loss Wasting of tissues Protein deficiency-adults Weight loss Wasting of muscles Enlarged liver Ederna Loss of vibratory sense Absent patellar and Achilles re flexes Motor weakness (squat test) Ederna Advanced polyneuropathy Beriberı heart disease Wernickes encephalopathy Retrobulbar neuritis Central ophthalmoplegia Protein deficiency--infants and children (Kwashiorkor) Growth retardation Depigmentation hyperpigmenta tion of skın Dyspigmentation of hair Enlarged liver Edema Peevish mental apathy Riboflavin deficiency Photophobia lacrimation burn ing and itching of eyes Soreness of lips and tongue Circumcorneal injection and corneal vascularization Cheilosis Angular maceration and fissures Glossitis--purplish color abnor malities of papıllae Nasolabial seborrhea Vitamin A deficiency Night blindness Xerosis conjunctivae Bitot s spots Dry scaling skin Follicular hyperkeratosis Thiamine deficiency Burning soles of feet Numbness and tingling of toes Calf muscle tenderness Hyperesthesia or hypesthesia of feet and legs Niacın deficiency Soreness and burning of tongue Chronic diarrhea Glossitis--1edness swelling serra tions abnormalities of papillae Pellagrous dermatitis Vaginitis and proctitis Mental changes-anxiety halluci nations, depression disorienta tion Encephalopathic states ·TABLE 6 LABORATORY PROCEDURES USEFUL IN NummONAL DIAGNOSIS Nutrient Laboratory test Normal findings rindings suggestlıc ol deficiency or other abnormally 6-8 gm/100 ml <6 g/100 ml 4-5.5 gm/100 ml <4 g/100 ml Protein Concentration of serum proteins Concentration of serum albumin Nitrogen balance (Kwashıorlor) Pancreatic enzymes in duodenal Juice Liver biopsy 0 or positie Present Negative Absent Normal Tatry Infiltration necrosis and/or fibrosis GENERAL OBSI RVATIONS Carbohydrate Glucose tolerance Blood glucose concentration Licaled blood glucose in dlabemes Fasting <130 mg/100 ml Maximum <180mg/100ml Little Increase in blood clexose In Malaborption 3 hr = or fasting Lipids Ela aidd in certain diseases (Soe rare 56) Serum cholesterol concentration Absorption Uncertain (200 mg/100 ml?) Marked rise in serum Fecal r low Low seruan and high Iecal rin malakxyption syndromes Fat balance (diet 100 gm fat) Vitamin A tolerance <5% fat in fores >5% fat in foros Increase serum Vitamin A Minimal rise serum Vitamin A in malabsorpilon to >200 48% ·20 NUTRITIONAL DIAGNOSIS more significant than a single deviation from normal Interpretation is not easy and must be considered in con junction with the dietary history and laboratory tests Some of the findings which are suggestive of specific nutritional deficiency are given in Table 5 and will be discussed in detail in subsequent sections A number of laboratory procedures have been de veloped which are useful in evaluating nutritional status While these will be considered subsequently in the discussion of each of the essential nutrients, a summary of normal values and of changes which may be observed in malnutrition is given in Table 6 GROWTH OF INFANTS AND CHILDREN In nutritional diagnosis in infants and children, ap praisal of growth and development in relation to age and sex is of great importance All types of nutritional deficiency may retard the rate of growth whether the defici ency represents an inadequate supply of calories, protein, vitamins or minerals Growth rate is influenced, too, by disease and it is necessary to determine whether an inadequate food intake, some pathologic process, or both, are responsible for retardation Assessment of growth implies a standard with which to compare the subject being examined Unfortunately, pres ent standards are far from precise and the optimal rate of growth remains unknown The standards which have been developed by investigators at Iowa and Harvard Unversities (8) or the Wetzel grid (9) are to be preferred to height weight age tables in evaluation of growth rate Genetic and environmental factors must always be con sidered in the use of such standards In any event, a single record of height and weight at a given age is of much less value than a long term record, since the latter ·TABLE 6 (Continued) Nutrient Laboratory test Normal findings Findings suggestive of deficiency or other abnormally Riboflavin Ruboflavin concentration In crythrocytes > 20 48 100/ml <14 mg 100/mi Niacin >5 mg in 24 hrs <3 mg in 24 hrs Urinary excretlon N'Me and pyridone on test dlet (See page 115) Vitamin B6 > 50 mg In 21 hrs Xanthurenic acid cxcre- <30 mg. In 24 hrs tion after 10 gm d 1 tryptophan Blood urca nitrogen 12 hrs Normal after 30 gm alanine GENERAL OBSTRVATIONS Llevated Folic Acid Complete blood count Normal MCV. 80-95 cu microns Bone MAITOW Norma! Urinary excretion after 5 > 2 mg mg folic acid orally Anemia >100 cu microns Megaloblastic <15 mg in malabsorption Vitamin B1# мсү• 80-95 cu microns Bone marrow Normal Schilling test (sec page 130) Excretion Co Bi >60 Serum Bus >100 pg/ml *MCV - Mean Corpuscular Volume >100 cu microns Megaloblastic Excretion Co Bus <26 <80 # MR/ml ·TABLE 6 (Continued) 22 Nutrient Laboratory test Normal findings Findings suggestive of deficiency or other abnormality Sodium Scrum sodrum concentration 140 mEq/iter Potassium Serum potassium concen tration 42 mEq/iter Usually decreased in deficiency increased in retention Often decreased in deficiency increased in retention (See page 77) Calcium Serum calcium concentra tuon 50 mEq/liter Decreased Iron <30% Mean corpuscular hemo 32 34% globin concentration Serum iron concentration 80-180 g/100 ml Serum iron binding ca 300-360 ug/100 ml pacity Hemosiderin in bone Present marrow <50 ug/100 ml >400 ug/100 ml NUTRITIONAL DIAGNOSIS 0 to trace Vitamin A 30-50 ug/100 ml <20 ug/100 ml Serum vitamin A concen tration Serum carotene concen tration 75 200 ug/100 ml <50 mg/100 ml Thiamine <50 ug in 4 hrs Urinary thiamme excretion 100-200 ug in 4 hrs after giving 1 mg paren terally Carbohydrate index (See page 107) <15 >15 ·GERAI ONSI RVATIONS is indicallic of ric of growth of the child in question In a scnsc, thic chuld l»ccomes liis own control and im provement or relrogression can bxc appreciated readily The nutritional or other cause of change sliould then be determined Another method of ci ilunting growth is estimation of shclctal malumtion Scicml proccdurcs for this has been deriscd (10) Many studies havc indicated the important influence of nutrition on the course of pregnancy and on tlic con dition of the infant at birth (11) Thic incidence of still births and prematurc births and the birth scight of full term infants is aflccled by milcmal nutritional statc Data relative to thcsc findings have been collected in ccrtain arcas and used in partial cu aluation of nutritional status of population groups Determination of height and wcight of school children also gives information which has proved uscful in nutrition surveys The rate of growth of chuldren is a scnsıtıyc index of food supply and dietary practices Conclusions from such data will be valid only if satisfactory standards are available for the population group in question or if comparison can be made between several homogencous scctions of the population Changes which occur following institution of programs designed to improve nutrition will also be informative ·TABLE 6 (Continued) 24 Nutrient Laboratory test Normal findings Findings suggestive of deficiency or other abnormality Ascorbic acid <01 mg/100 ml <2 mg/100 ml Plasma ascorbic acid con 06 to 10 mg/100 ml centration Ascorbic acid concentra 20-30 mg/100 ml tion in WBC-platelet layer Serum concentration 4 hrs >04 mg/100 ml after parenteral dose of (Infants) <04 mg/100 ml 200 mg Vitamin D (infants) Alkaline phosphatase Serum phosphorus 5 15 Bodansky Units 25 36 mEq/1 >20 Bodansky Units <25 mEq/1 NUTRITIONAL DIAGNOSIS Vitamin E Serum tocopherol concen tration (adults) (infants) Erythrocyte hemolysis 10 1.2 mg% 0.23 0 43 mg% Normal Decreased Decreased Increased Vitamin Prothrombin time 10-15 seconds Prolonged ·CALORIC NUTRMON 27 further knowledge The height scight standards riscul currently represent antlımcllc avcrages of findings in selected population groups In most instanccs, data were obtained at the time of application for Insurance, the in dividuals being ucighed and mcasured in ordinary clothes (14) The incxactness of such standards is apparent Clothing and hcight of heels introduce appreciablo varıables In some standards, as crage scights arc gncn for light, medium and heavy body types No accurate method of determining body build is available although a rough appraisal can be made by the experienced clinician Mca. surcment of bi-cristal (bi ilac) duamctcr is of assistancc (15) Determination of bı acromial diameter is also useful but is more difficult to obtain accurately, due to the influence of posturc on this mcasurement Genclıc vanations and cnvironmental factors, such as climate, should be taken into account in hcight weight appraisal Available standards are uscful if intcrprctations are made with appreciation of their inexactness An individual who is less than "standard" wcight may be lean, or have poorly developed muscles or a small skeleton An individual whose weight excceds the standard may be excessively fat, or may have a large muscle mass or a large sheleton It would be desirable to estimate the relative proportion of the components of the total body mass, namely, bones, muscles, extracellular fud and adipose tissues Recently, biophysical and biochemical methods have been devised for estimation of body composition and have been applied in evaluation of leanness and fatness in man (16) Total body fat may be estimated by determining the specific gravity of the body, by estimating total body water, and by measurement of the thickness of subcutaneous tissues, ·CALORIC NUTRITION DLACNOSIS LAGNOSIS of caloric undernutrition or over nutrition is relatively easy if deviation from the normal is great but minor deviations cannot be determined with precision The dietary history is of some assistance in estimating the extent of caloric deficit or surplus in spite of the difficulties in ascertaining daily food consumption accurately Knowledge of energy requirements according to age, sex, body size and physical activity is necessary for interpretation of findings Approximate caloric needs of populations groups, and to a lesser extent of individuals, may be determined with the use of schedules prepared by several national and international groups (4, 12) The requirement for an individual may be obtained more accurately by calculating his basal metabolic needs and adding the amount required for physical activity The importance of calories during growth was emphasized by Macy and Hunscher (13) who pointed out that as few as 10 calories per kilogram of body weight per day may may make the difference between progress and failure METHODS FOR EVALUATION In evaluating height and weight in children, growth charts may be used but interpretation should be cautious Ideal weight for height is not known for either children or adults In adults, desirable weight may be considered to be the average weight, for a given height and type of body build, of persons 25 years of age who are in good health More precise definition of ideal weight must await 26 ·CALORIC NUTRITIOV Muscular des clopment of an induidul can bc csti mated by deternining the breadth of the muscular seg ments of soft tissic x rys of thic cxtrcmitics Somc Infor mation can be obtaincd by mersurcincnt of limb circum. ference of thickness of the skin and subcutancous fat is detcrmincd at the same time With application and improiement of tlıc mcthods indicated aboic, diagnosis of caloric nutriturc should become morc cxact It is anticipated that morc adequate "norms" as "standards” will be descloped for population groups of varying genclic potentialitics and cnvironmental situations CALORIC OVERNUTRITION The serious mcdical hazard of obesity is attested by insurance data which indicate that if the death rate of the standard risk is taken as 100, the mortality of men who are moderately overweight is 142 and of those markcdly overweight 179 The respective values for women arc 142 and 161 (21) Overweight as judged by standard height weight age tables docs not necessarily mcan obesity which should be defined as a disproportionately large fit content of the body The incidence of diseases of the heart, arteries and kidncys, of diabetes mellitus, of gallbladder disease, and even of neoplasia is increased in persons who are overweight (21) Important information might be obtained by application of the newer methods of estimating body composition in examination of overweight persons in whom various pathologic conditions have developed The recent implication of lipids in the patho genesis of atherosclerosis has stimulated interest in this field (See p 53 ) Much remains to be learned about the role of excessive fat accumulation and of lipid metabolism in the pathogenesis of disease However, sufi ·28 NUTRITIONAL DIAGNOSIS muscle and bone in x ray photographs (16, 17) Mc Cance, Williamson and associates (18) calculated body fat either from total body water, or by subtracting the weight of the extracellular flud, cell mass and minerals in the skeleton, from the total body weight Minerals were esti mated as 7% of the fat free body The weight of cellular tissues was determined by assuming that cells contain 67% water and estimating intracellular water as the difference between total body water and extracellular space Keys and associates (19) suggested estimation of cell or 'active' tissue mass as body weight less fat, extracellular fluid and bone mineral, fat being determined from body density These methods are of importance in research and may be used as criteria for evaluating simpler procedures which the clinician can apply An indirect method for estimation of fatness or leanness which seems promising is measurement of the thickness of skin folds in several areas of the body with specially constructed calipers Good correlation has been demon strated in adult males between findings with this method and determination of specific gravity of the body (16 17) Correlation has also been demonstrated between pinch caliper and x ray measurements of the thickness of skin and subcutaneous fat (20) The use of skinfold measurements as criteria for evaluating fatness or leanness of the body requires further study Data available at present suggest that measurements of skin fold thickness at two sites are of value the back of the right upper arm and below the tip of the right scapula Details of the pro cedure are given in a recent publication in which other anthropometric measurements for characterization of nu tritional status are also discussed (15) Skinfold measurements in a large group of young American males, white and negro, are included in this report ·CALORIC NUTRITIOV 31 Intory findings include body cardin, hypotension, rcduccd peripheral circulation and decrcised vcnous pressurc Tho body temperaturc is lowered and there is a dccrcasc in the reactivity of thc organism to various stimuli Ncuro. logical cxamination often shows diminished or abolished decp tendon rcllcxcs but sensory mechanisms arc maintained in most instances Signs of depressed function of the endocrine system, particularly of the scx glands, arc common, amenorrhci, sterility and loss of libido being frequent findings The patient looks, feels, and acts prematurely old Polyuria, increase in fluid intake and salt hunger are often observed Osteomalacia is an occasional finding in prolonged star ation Edema is frequently encountered and may mash the extent of decrease in body weight If protein deficiency is scvere, the cdcma may be cven more extensive and anemia, often of macrocytic type, may be present Signs of vitamin deficiency occur only if the diet has been deficient in these factors Starvation, as observed in concentration and prisoner of war camps, particularly in the Orient, was accompanied in many instances by peripheral neuropathies, retrobulbar neuntıs, deafness, encephalopathy and other neurologic syndromes Some manifestations responded to therapy with B complex vitamins while others were unaffected In severe prolonged undernutrition, basal metabolic rate declines, the decrease in basal orygen consumption applies to active metabolizing tissue as well as to the whole organism The fastıng blood sugar may be low and tolerance for glucose diminished In sem starvation experiments with human volunteers blood pyruvate rose to abnormally high levels after exercise (19) Studies of body composition in these experiments in which an average of 16 kg in weight was lost in 24 weeks, indicated no ·30 NUTRITIONAL DIAGNOSIS cient information is at hand to indicate the desirability of maintaining normal body weight and avoiding excessive fatness CALORIC UNDERNUTRITION Caloric undernutrition occurs primarily as a result of a limited food supply, exemplified by semi-starvation and starvation, and secondarily as a consequence of many pathologic states, particularly those associated with an increase in metabolism or with anorexia or gastrointestinal disturbances The loss of potential calories in diarrheal diseases, especially in steatorrheas, may be extensive In diabetes mellitus glycosuria is a manifestation of caloric loss Caloric balance can be maintained over a fairly wide range of body weight and caloric intake in a given indı vidual A continued loss of weight beyond 10% may be considered evidence of caloric deficit Weighing a patient at frequent intervals is the best single method of determining caloric balance although fluctuations may repre sent changes in fluid rather than in metabolic mass, es pecially in acutely ill patients The primary findings in caloric undernutrition, in addition to weight loss, are wasting of muscles weakness and lethargy Nitrogen balance is negative and deficiency of protein complicates the clinical picture The previous state of nutrition, the character of the diet and the manifestations of primary disease, when such is present, influence findings In severe starvation, apathy, weakness and wasting of muscles become extreme and the patient literally appears to be nothing but skin and bones Mental and emotional changes are common and are reflected in behavior Pig mentary changes in the skin have been observed Cucu- ·CALORIC NUTRITION knowledge of the possiblc cflccts of malnutrition or its residues on susceptibility to, or on thic course of, other discascs Simple undcmutrition tends to hasc a favorable influence on diabetes and a detrimental cffect on tubcrculosis Psychological residucs of star ition nrc probably of great importance but hasc rocci cd little study ·32 NUTRITIONAL DIAGNOSIS significant change in bone mineral or in extracellular fluid, a marked decrease in body fat and a lesser but sig nificant decrease in active metabolizing tissue On a percentage basis, the body contained less fat and muscle but more water This excess fluid may explain, at least in part, the occurrence of starvation edema For a review of the biochemical and physiological changes in starvation, refer ence is made to the compilation published by Keys and associates (19) In caloric undernutrition, the extent of the weight loss is an important factor in prognosis If the loss is 30% or less in previously healthy persons, full recovery may occur with proper care A loss of more than 40% is serious, al though recovery is at times possible Caloric undernutrition which is secondary to disease may be manifested by many of the findings just described, in addition to the signs characteristic of the primary path ologic process Another finding worthy of emphasis is that starved persons are poor surgical risks Extensive loss of weight may lead to altered hepatic function, contracted blood volume reduced capacity to control infections and impaired wound healing Furthermore it is difficult to determine when rehabilitation is sufficiently advanced to undertake surgery Knowledge of the residues of serious undernutrition, the late or permanent effects is limited Children seem to recover completely from caloric restriction if the duration is not more than a year or two Residues of severe or pro tracted malnutrition, in formerly healthy soldiers who had been in pnson camps have included excessive fatigue, weakness, inability to maintain proper weight, general "nervousness," excessive sweating paresthesias visual defects including optic atrophy, hernias cardiac and gastrointestinal complaints and osteopathy There is little ·PROTTE Nummoy growth is most mpid, and during thic Inter hall of preso nancy and in lactation The recommended protcin allosance for maintenance in adult life is 10 pn pr lilo gram of body ucight drils (Table 3) Tic minimal sco quirement of thc cight csscntial amino acids for adult men (22) and women (23) arc shown in Table 7 l'art of the requirement of pheny Irlaninic inny lxc supplied by tyrosinc and part of the methioninc requirement by cy's tinc Sufficient nitrogen must also ly ſumished by thic dict for manufacture of thc noncsscntial amino acids Somc ini estigations of the amino acid neces of infants 1171c becn reported (21) No precise information is available for childhood and adolescence The quality of dictar, protein is dependent on amino acid content Animal proteins which contain all the essentral amino acids have greater biological valuc than do Vegetable proteins which arc often deficient in one or more of these imino acids Numcrous methods, direct and indirect, hasc been suggested for determining the biological value of proteins These have been reviewed in a recent symposium (17) The proportionate rcquirements of essential amino acids for maintenance of nitrogen equilibrium in mun appear to be similar to those of growing animals for maximum nitrogen retention Mitchell (17) has suggested the use of an essentil amino acid index” in assessing the nutritive value of food proteins This index shows a high correlation with biological valuc as obtained in animal experiments Investigation has shown that not only must all the essen tial amino acids be included in the diet but they must be present at the same time and in the proper proportions Thus, the amino acid balance of the diet is a factor requiring consideration in evaluating protein nutrition (25) Recently an attempt has been made to devise a theo- ·PROTEIN NUTRITION MALNUTRITION due to an inadequate supply of protein of good quality is probably the most important deficiency syndrome in the world today other than caloric undernutrition Protein deficiency may be primary, or occur in association with caloric deficiency, or be secondary to a wide variety of pathologic conditions Deficiency is common in prolonged febrile illnesses, hyperthyroidisin and other diseases associated with hypermetabolism It is encountered in the many conditions in which protein is lost from the body such as the nephroses, effusions into serious cavities, exudates and weeping wounds Deficiency is observed, also, in diseases which impair digestion or absorption and in metabolic disturbances which interfere with utilization Negative nitrogen balance commonly follows trauma such as fractures, burns and operative procedures and may persist for weeks Nitrogen loss may amount to as much as 0 6 gm per kilogram of body weight daily, which represents a loss of 375 gm of protein per kilogram PROTEIN REQUIREMENT AND DIETARY EVALUATION In approaching the diagnosis of protein deficiency, it is essential to know the requirement of protein and of the eight amino acids which have been found to be dietary essentials for man The minimal requirement of protein for the adult is in the neighborhood of 05 to 065 gm per kilogram of body weight daily Larger amounts are needed during the period of growth, being greatest when 34 ·TROTTN NUTR1701 retically optimal protcin with pmper balance of amino acids with which thc intalc of dicting protein may ix compared (251) This should proic useful in calunting the protein suppls of population groups or cien of indi. viduals Undoubtedly, revisions of this provisional "opti. mal" amıno ncid piltem will bc forthcoming as it is tested under varying conditions Schocnheimer (1) and others lizic demonstried that proteins are constantly being broken down and reconstituted, and that there is a constant interchange between amino acids in tissuc protein and free amino acids Accordingly, a continuous supply of amino acids is nccded in the dict Sprinson and Rittenberg (20) have estimated that the time needed for half replacement of body protein in man is about 80 days The rate of amino acid crchange varies in different tissues thc turnos er in lover and plusmı accounts for 41% of the total erchange in man Lihenisc, depletion of tissuc proteins during the des clopment of deficiency is not uniform some proteins being dcplctcd more rapidly than others and some tissucs more severely than others (17) An adequate supply of calories from non protein sources is important in proper utilization of protein so that amino acids may be spared for protein synthesis and other vital functions, rather than being utilized for energy The functions of protein in the body are many Amino acids are used in the synthesis of cellular proteins of all tissues, of special proteins such as hemoglobin, albumin, globulin fibrinogen etc and in the formation of enzymes, hormones, and antibodies Amino acids are important in transmethylation and detoxification reactions some of them have lipotropic function In addition they may be deaminated and the remainder of the molecule transformed into glucose or fatty acids which are utilized for ·36 TABLE 7# AVERAGE MINIMAL REQUIREMENTS FOR ESSENTIAL AMINO ACIDS AS DETERMINED BY DIFFERENT WORKERS Isoleucine Leucine Lysine Phenylalanine Sulfur containing Amino Acids Threonine Trypto Valıne Methionine Cystine Total phan Average minimal needs milligrams per kilogram body weight Infants 90 90 90* 85 60 30 0 pres. 85 Men" 104 99 88 15 13.2 116 65 2.9 43** 13.3*** 31**** 8.8 Women" 5.2 71 33 35 131 13.2 52 60 6.8 7.2 2.1 47 38 34 30 9.2 05 (2.2) 34 (4.2) NUTRITIONAL DIAGNOSIS #(Reproduced from Protein Requirements, FAO Nutrition Studies No 16 Food and Agriculture Organization of the Uruted Nations, Rome, 1957-reference 25a ) Tyrosine present 159 mg tyrosine per kg--ratio of tyrosine to tryptophan equals 55 *** No tyrosine **** 156 mg tyrosine per kg-ratio of tyrosine to tryptophan equals 74 Recent evidence indicates that 80-85% of the methionine requirement is replaceable by cystine and 70-75% of the phenylalanine requirement is replaceable by tryosine.

·PROTEN NUTRITIOV 39 deficiency may be maslcd ly decreasc in blood volume Wulc determination of blood volume is difficult and not always satisfactory, cstimation of total circulating scrum albumın is a more accurtc mcthod of detecting protein depiction than is measurement of concentration of scrum albumin Cicn small dccrcises in scrum albumin rcprcsent loss of tissuc protein of considerablc magnitude On the basis of animal crpcriments, it may be assumed that cach gram of decrease in total circulating albumin rcprcsents a loss of approximately 300 gm of tissuc protein (28) Several ycars ago, Harroun and associates (29) suggested estimating crtravascular resencs of protein (interstitial fluid and lymph) by determining the response to rapid infusion of one liter of isotonic sodium chloride Normal persons show cd an incrcase in plasma volume and in total circulating protcin, wlule malnourished subjects showed a smaller increase in plasma volume and a decrease in total circulating protein Further evaluation of this procedure seems indicated Electrophoretic analysis of serum proteins has not proved of value in the diagnosis of protein deficiency which accompanies calorc undemutrition (30) Studies of antibody response in subjects with abnormal levels of serum protein have failed to show a relationship between the concentration or distribution of serum protein fractions and the ability to form antibodies (31) In protein deficiency, nitrogen balance is negative Since balance studies require special facilities they are more useful in research than in medical practice Furthermore, many difficulties are inherent in the interpretation of nitrogen balance data Simultaneous depletion and repletion of various compartments of body protein may ·38 NUTRITIONAL DIAGNOSIS energy or stored as fat Thus, proteins are vital for growth, reproduction, maintenance of health and rehabili tation from injury PROTEIN DEFICIENCY In the diagnosis of protein malnutrition, the first steps are determination of the approximate dietary supply of protein from a quantitative and qualitative standpoint and recognition of the pathologic conditions which are prone to lead to protein deficiency Physical findings common to most protein deficiency syndromes are loss of weight (unless mashed by edema), decrease in subcutaneous fat, weakness, muscle wasting, edema and accumulation of fluid in serous cavities Frequently, hypotension, brady, cardia and pigmentary changes in the skin are observed and the basal metabolic rate may decrease Protein deficiency may lead to fatty infiltration and cirrhosis of the liver Anemia, which may be normocytic or macrocytic, is a frequent accompaniment of chronic protein deficiency syndromes Protein deficiency increases the risk of surgery and is associated with poor healing of wounds Heart disease of unexplained cause has been reported to be prevalent in certain areas of the world where pro tein malnutrition is common Gillanders (27) in South Africa has described heart failure in association with large, hypodynamic, dilated but often not hypertrophied hearts Whether protein deficiency is responsible for this syndrome or for the endomyocardial fibrosis which occurs in Uganda remains unknown but is a distinct possibility The most important laboratory finding in severe protein deficiency is a decrease in serum proteins particularly in the albumin fraction Normal concentration of total proteins in serum is 60-80 gm/100 ml, of albumin 40 to 55 gm /100ml The decrease in concentration in protein ·PROTEIN NUTRITIOV MGURE 1 MICWOLI NA LITE 3 PLASMA taurine o-partic threonie sering csporogine glutamic proine glycme alanine cystine voline methionine isoleucine leucine Tyrosine phenyldanine histidine tryptophane ornithine fysine arginine ethanolamine aminois cout yric MICROMOLS PER DAY pool URINE Taurine aspartic threonine serine asparagine glutamic protne glycme alanine cystine valine methionine Isoleucine leucine tyrosine phenylalanine histidine tryptophane ornithine lysine orginine ethanolamine omninoisobutyric Fig. 1 * Concentrations of individual amino acids in plasma of normal adults and daily urinary excretion of frec araino acids by normal adult males * Reprinted from Harrison, H. E, and Harrison, H. C. JAMA, 164, 1572, Aug 1957 ·40 NUTRITIONAL DIAGNOSIS not be detected and it is possible to obtain positive bal ance when some labile protein stores are being depleted Recent studies indicate that tissues enzymes respond to changes in dietary protein It seems likely that measure ment of enzyme activity in tissues may prove useful in determming the presence and severity of deficiency and, perhaps, deficiency of specific amino acids The liver would appear to be a good organ for study as changes in enzyme activity of the liver have been found to accom pany variations in exogenous protein intake (17) Numerous methods for determining the concentration of amino acids in blood and urine are available Tech niques include chemical and microbiologic assay and chromatography using paper or son exchange columns Amino acid determinations have been of value in detecting metabolic derangements but have been of little assist ance in evaluating over all protein nutrition The amino acid content of plasma during fasting does not fluctuate significantly despite considerable variation in amounts ingested (32) and does not parallel quantities excreted in the urine due to marhed differences in reabsorption of individual amino acids by the renal tubules (33) Diets high in protein are, however, associated with slight in creases in 24 hour excretion of amino acids particularly with respect to histidine Normal plasma levels and pat tern of urmary excretion are given in Fig 1 Excretion can be increased by either of two mechanisms, hyperaminoacidemia or changes in renal tubular absorption Abnormal excretion of amino acids has been reported in advanced Iner disease and after radiation injury but not following surgical procedures when nitrogen balance is negative (34) Diseases associated with aminoaciduria have been re viewed by the Harrisons (33) Specific aminoaciduria of ·PROTTIN NUTRITOV 43 in reduction of the aminoaciduria in the ranconi synidromc Under ordinary dictar conditions, the loss of amino acids in the unne has not been found to be sufficiently great to producc dcficicncies The only significant disturbancc directly duc lo crccssisc crcrction of amino acids is the formation of cystinc calcul in the urinary tract in cystanuna (33) From data just discussed, it is cuidcnt that cstimation of excretion of individual amino acids is a useful procedure in the diagnosis of a number of discascs associated with metabolic abnormalities Such determinations arc useful also in clarifying interrelations among these discascs and among vitamins and amino acids SPECIFIC AMINO ACID DEFICIENCIES Little is known about specific amino acid deficiencies in man Albanese (36) has suggested that changes in amino acid levels in blood and urine may be useful in detecting certain deficiencies Turther investigation will be needed to substantiate this postulate Tryptophan is known to be a precursor of the vitamin niacin, and hencc an inadequate dietary supply of tryptophan contributes to the development of niacın deficiency or pellagra (37) Methionine metabolism has been widely investigated in animals but little is known about the application of findings to man Relationships between methionine choline vitamin B12 and folic acid have been observed in animals Each of these nutrients participates in some way in the metabolism of methyl groups Such groups are important in the prevention of fatty livers and cirrhosis in animals which are fed diets high in fat or low in protein and low in fat It seems likely that methyl groups are of similar importance in human nutrition ·42 NUTRITIONAL DIAGNOSIS hyperaminoacidemic type occurs in phenylketonuria (phenylpyruvic oligophrenia), an inborn error of metabo Iism In this condition, conversion of phenylalanine to tyrosine is defective, phenylalanine levels in plasma are markedly increased and urinary excretion is correspondingly high The aminoaciduria of severe liver damage is due to generalized hyperaminoacidemia but taurine, cy, stine, methionine, ethanolamine and ß aminobutyric acid are found in larger amounts than in other types of general aminoaciduria Aninoacidurias of renal origin include a number of con ditions, some due to inborn metabolic errors, some to touc agents and others to vitamin deficiency states In patients with scurvy and in premature infants, the feeding of high protein diets leads to hydroxyphenyluria The abnormal excretion of hydroxyphenyl derivatives may be prevented by giving ascorbic acid or large amounts of folic acid (35) Renal aminoaciduria has been reported in infants with vitamin D deficiency (33) The excretion of free amino acids in rickets is qualitatively similar to that found in the Fanconi syndrome although less marked The greatest increases in excretion are in threonine, serine and alanıne with slight increases in valine, methionine, leucine, iso leucine and phenylalanine The Fanconi syndrome, which is characterized by bony changes of richets or osteomala cia hypophosphatemia glycosuria and renal aminoacid uria, may be due to an hereditary metabolic abnormality or occur in older children or adults without familial inci dence The fundamental defect appears to be renal tubu lar injury, especially of the systems involving amino acids, glucose and phosphate Treatment of rickets with vitamin D leads to a gradual return of amino acid excretion to normal Administration of large does of vitamin D results ·PROTTN NUTRITION studying many of the syndromes associated with protein dcficicncy Certain other changes in cirrhosis of the liver which arc of nutritional import may be mcntioned, al though they arc not related directly to protein nutrtion An incrcuscd loss of fnt in the stools has been obscricd that has been postulated to be duc to dcfcctive formation of bilc salts (42) In dccompensated alcoholic cirrhosis, scrum concentrations of sodium, potassium, calcium and phosphorus have been found to be lower than normal, whule pyruvic acid concentration in the blood has been elevated (13) Thc los calcium and phosphorus les cls may have been due to an incrcase in fccul fat In hepatic coma, concentrations of pyrui atc and a keto glutarate have been found to be high in both blood and spinal fluid Since thiamine administration does not influence these levels, it has been postulated that the liver may be unable to assimilate pyruvic acid to form the carboxylic acids of the Krebs cycle or that 7 partul defi ciency of cocarborylase may be responsible High blood ammonia concentrations have been observed, also, in hepatic coma (44) It has been suggested that high con centrations of heto acids in hepatic coma may represent a defect in intermediary metabolism due to impaired utilization of ammonia and faulty removal from the blood by the diseased liver THE WASHIORKOR SYNDROME In many areas of the world, infants and young chil dren develop a syndrome of protein malnutrition that is of serious import This condition is designated Kwa shiorkor in Africa (38) and Syndrome Policarencial Infantil in Central and South America (45) The primary cause of kwashiorkor is a diet deficient in protein of good quality and the disease appears in the age groups where ·44 NUTRITIONAL DIAGNOSIS PROTEIN NUTRITION AND CIRRHOSIS OF THE LIVER While the role of nutrition in the pathogenesis of cirrhosis of the liver in man has not been elucidated in its entirety, evidence from many sources suggests a relation ship between a deficient intake of protein and the de velopment of fatty infiltration, cellular necrosis and fi brosis of the liver (38) The dietary history of many patients with cirrhosis indicates a low intake of protein and of B complex vitamins The institution of a diet rich in protein has been followed by improvement in the clinical condition of the patient and in liver function tests Eckhardt and associates (39) found that provision of a diet adequate in protein resulted in a decrease in liver fat and a return of the size and appearance of liver cells to normal In patients with untreated cirrhosis in whom biopsy specimens showed fatty infiltration of the liver, adminis tration of a large single dose of methionine or choline has been shown to increase phospholipid turnover (40) Studies of Kirsner (41) suggest that in patients with cirrhosis amino acids other than methionine may be metabolized adequately although less efficiently than normal In acute severe hepatitis concentrations of me thionine in plasma are greatly increased A high protein intake is contraindicated under these circumstances and in impending hepatic coma A detailed discussion of the diagnosis of cirrhosis is not warranted here but it seems pertinent to emphasize the importance of searching for evidence of liver dysfunction in the presence of serious dietary deficiency of protein A palpable liver abnormal liver function tests and histologic changes in liver tissue obtained by biopsy will es tablish the presence of liver disease Measurement of enzyme activity in biopsy specimens may prove useful in ·PROTETY NUTRITIOV studying miny of the syndromes associated with protein deficiency Certain other changes in cirrhosis of the liver which arc of nutritional import may be mentioned, al though they arc not related directly to protein nutrition An increased loss of fat in the stools has been obscrcd that has been postulated to be due to dcfcctic formation of bic salts (42) In decompensałcd alcoholic cirrhosis, serum concentrations of sodium, potassium, calcium and phosphorus have been found to be lower than normal, while pyruvic acid concentration in the blood has been elevated (43) Thc low calcium and phosphorus les cls may have been due to an increase in fecal fat In hepatic coma, concentrations of pyrus itc and a lcto glutarate have been found to be lugh in both blood and spinal fluid Since thiaminc administmtion does not in. fluence these les cls, it has been postulated that the liver may be unable to assimilatc pyruvic acid to form the carboxylic acids of the Krebs cycle or that a partial deficiency of cocarboxylase may be responsible High blood ammonia concentrations have been obsercd, also, in hepatic coma (44) It has been suggested that lugh concentrations of leto acids in hepatic coma may represent a defect in intermediary mctabolism due to impaired utilization of ammonia and faulty removal from the blood by the diseased liver THE WASHIORKOR SYNDROME In many areas of the world, infants and young child dren develop a syndrome of protein malnutrition that is of serious import This condition is designated Kwa shiorkor in Africa (38) and Syndrome Policarencial Infantıl in Central and South America (45) The primary cause of kwashiorkor is a diet deficient in protein of good quality and the disease appears in the age groups where ·44 NUTRITIONAL DIAGNOSIS PROTEIN NUTRITION AND CIRRHOSIS OF THE LIVER While the role of nutrition in the pathogenesis of cirrhosis of the liver in man has not been elucidated in its entirety, evidence from many sources suggests a relation ship between a deficient intake of protein and the de velopment of fatty infiltration, cellular necrosis and fi brosis of the liver (38) The dietary history of many patients with cirrhosis indicates a low intake of protein and of B complex vitamins The institution of a diet rich in protein has been followed by improvement in the clinical condition of the patient and in liver function tests Eckhardt and associates (39) found that provision of a diet adequate in protein resulted in a decrease in liver fat and a return of the size and appearance of liver cells to normal In patients with untreated cirrhosis in whom biopsy specimens showed fatty infiltration of the liver, adminis tration of a large single dose of methionine or choline has been shown to increase phospholipid turnover (40) Studies of Kirsner (41) suggest that in patients with cirrhosis, amino acids other than methionine may be metabolized adequately although less efficiently than normal In acute severe hepatitis, concentrations of me thionine in plasma are greatly increased A high protein intake is contraindicated under these circumstances and in impending hepatic coma A detailed discussion of the diagnosis of cirrhosis is not warranted here but it seems pertinent to emphasize the importance of searching for evidence of liver dysfunction in the presence of serious dietary deficiency of protein A palpable luer, abnormal liver function tests and histo logic changes in liver tissue obtained by biopsy will es tablish the presence of Irver disease Measurement of enzyme activity in biopsy specimens may prove useful in ·PROTEIN NUTRITION 47 color, and falls out readily In older children, the "flag" sign may be obscrved when the hair is held up away from the scalp, stripes of normal color and of depigmen tation may be noted, presumably signifying periods of dietary improvement and inadequacy, respectively ractors responsible for these changes in the hair have not been elucidated It has been postulated that deficiencies of sulfur containing amino acids or of B complex vitamins may be responsiblc Alterations in function of the lidneys and hcart have been reported in kwashiorkor Oliguria is frequent and electrocardiographic changes have been observed The latter include diminished amplitude of all deflections and prolongation of the Q-T interval (46) Laboratory findings in kwasluorhor include anemia which may be normocytic or slightly macrocytic, the bone marrow shows relative hypoplasia of the erythroid series (46) There is a decrease in pancreatic enzymes as determined by duodenal intubation and low levels of serum amylase, esterase, lipase and alkalme phosphatase are observed Serum protein concentration is reduced markedly, especially the albumın fraction Specimens of liver obtained by biopsy show fatty infiltration, cellular necrosis, fibrosis or a combination of these changes Waterlow (47) has found a fall in liver pseudo-cholinesterase paralleling the fall in plasma proteins Skim milk powder has been found to be effective in the treatment of kwashiorkor and its use has led to marked reduction in mortality Recently, pure casein and amino acid mixtures have been shown to initiate recovery (48) Complete rehabilitation may require many months even though an adequate diet high in protein is administered Undoubtedly many mild cases of kwashiorkor go unrecognized even in endemic areas, until intercurrent ·46 NUTRITIONAL DIAGNOSIS protein need is greatest Manifestations of this syndrome vary somewhat from one area to another due, in large part, to differences in diet, in some localities, caloric undernutrition and vitamin deficiency exist concomitantly with deficiency of protein Kwashiorkor is extremely rare in the United States although isolated cases have been observed The fundamental signs of kwashiorkor in Africa are retarded growth in the late breast feeding, weaning and post weaning period, alterations in pigmentation of the skin and hair, edema, fatty infiltration, cellular necrosis or fibrosis of the liver and a high mortality unless good dietary protein is provided (38) Atrophy of the acını of the pancreas is considered by several investigators to be a fundamental lesion In central America deficiency of calories and vitamins often complicate the clinical picture (45) In this area unlike Africa, the incidence of kwashiorkor is relatively high in children more than four years of age and may be seen up to the age of twelve Other features of kwashiorkor which are commonly encountered include dermatoses, gastrointestinal disturb ances such as anorexia, digestive upsets, diarrhea and steatorrhea peevishness and mental apathy, and anemia The shin lesions are multiple in type bizarre in appear ance, and have been designated "crazy pavement” dermatosis Hyperpigmentation is frequent, with lesions which resemble pellagra, except for their distribution which is generalized rather than limited to areas exposed to sunlight or trauma Vascular changes hyperkeratınızation and secondary infection are often observed The etiology of the skin lesions is uncertain vitamin acıd, or multiple deficiencies have been implicated The hair becomes "dyspigmented,” often assuming a reddish amino ·CARBOHYDRATE NUTRITION THERE is no true dietary requirement for crbohydrate since it can be synthesized in the body from either protein or fat Carbohydrate is utilized chiefly as 1 source of cnergy and furnishes 50 to 60 per cent of the calories in the average American diet It is more efficient than protein or fat in providing fuel for muscular exercise Carbohydrate has an antıketogenic action in that it inhibits the breakdown of fatty acids in the liver and it has a protein sparing action by decreasing the rate of deamination of amino acids Carbohydrate is essential for normal function of the heart and nervous system, the latter using only glucose to supply energy needs The concentration of glucose in the blood must be maintained above a cntical level or serious damage may ensue, par ticularly to the brain or myocardium The hemostatic mechanisms responsible for maintaining a relatively constand level of blood glucose include enzymatic, nervous and hormonal components (49) Carbohydrate is stored in the liver and muscles in the form of glycogen the extent of stores varying with the type of diet ingested Glycogen stores are highest when the diet contains large amounts of carbohydrate, intermediate when the diet is high in protein and lowest when the diet is high in fat Diets rich in carbohydrate protect the liver against injury by ensuring adequate storage of glycogen Carbohydrate has a detoxifying action in the liver, acetyl groups derived from carbohydrate are used in 49 ·48 NUTRITIONAL DIAGNOSIS infection or parasitism precipitates the characteristic syn drome Further investigation should elicit early findings and lead to recognition before the disorder has become advanced In regions of the world where kwashiorkor is common, a high incidence of chronic liver disease, not only cirrhosis but also primary carcinoma, is observed in adults Rela tionships of these pathologic changes to chronic protein malnutrition require further investigation PROTEIN NEEDS FOR REPLETION In planning nutritional rehabilitation of a patient with protein deficiency, certain findings in studies of protein repletion in animals appear pertinent It has been shown that the utilization rate for a particular essential amino acid for repletion exceeds the rate for maintenance by a factor of 2 to 5 On this basis, the protein needs of de pleted patients would be at least double those of normal subjects (17) The severity of protein depletion can be estimated only grossly with present techniques The fol lowing data considered together, should prove helpful the amount of weight lost (actually the loss of muscle and other active metabolizing tissue), the extent of the decrease in total circulating plasma protein particularly albumın, and in tissue proteins as reflected by this de crease (see p 39) and the daily loss of protein or nitrogen in urine stools, erudates and effusions It should be remembered also that amino acid requirements for repletion of specific tissue proteins vary according to the structure of the protein and the position it holds in the dynamic state of the body (17) ·CARBOIDRATE NUTRITION 51 persons crcrctc less than 01 per cent glucose in thc urine, an amount not detectable with the usunl clinical laboratory procedures An incrcise in glucose cicrction and an abnormally high concentration of glucose in the blood in the post absorptic statc (grciter than 130 mg/ ml/) is suggestic cydence of dubetes mellitus The glucose tolerance test assists in cstablishing the diagnosis, the blood sugar riscs to Icels abovc 170-180 mg/100 ml and remains clevated for three hours or more The blood sugar response to oral administration of a large dose of glucose is dependent in part on the previous dret Glucose concentration increases to a grciter extent and for a more prolonged period when the dict has been high in fat than when it has been high in protein, the elevation is still less and of shorter duration when a high carbo hydrate diet has been consumed In starvation the glu cose tolerance test is similır to that observed following administration of a diet high in fat, the increase in blood glucose concentration resembles, in degree and duration, that found in diabetes mellitus although the fasting blood sugar level tends to be low In sprue nutritional macrocyptic anemia and some vitamin B complex deficiency syndromes a flat glucose tolerance test is observed i e glucose concentration rises very little after administration of a large oral dose Ad. ministration of folic acid or vitamin B12 improves glucose absorption in sprue and nutritional macrocytic anemia in most instances (50) Many factors influence the absorption of glucose from the intestinal tract These include the food mixture in the intestine the status of the intestinal mucous membrane the function of the endocrine glands particularly the thyroid anterior pituitary and adrenal cortex and, as noted above the intake of vitamins of the B compler Absorption ·50 NUTRITIONAL DIAGNOSIS acetylation of numerous compounds and glycuronic acid, a carbohydrate derivative, combines with phenolic hy droxal groups This latter reaction may be important in regulation of the metabolism of steroid hormones and in prevention of excessive accumulation of the sex hormones in the body A number of the coenzymes involved in the degradation and synthesis of carbohydrates are formed from vitamins of the B complex Coenzymes containing thiamine, ribo flavin, niacinamide, vitamin Bs and pantothenic acid have vital roles in intermediate carbohydrate metabolism Ac cordingly, diets rich in carbohydrate require a generous supply of these vitamins and an inadequate quantity of any one of them will prevent metabolic processes from proceeding normally This information is applied in the diagnosis of deficiency of one of the B vitamins, thiamine in which pyruvic acid an intermediate in the breakdown of glucose accumulates in the blood and tissues (See p 107 ) Much has been learned in recent years about the hormonal regulation of carbohydrate metabolism, of the roles of insulin and of the adrenal and pituitary hormones This subject will not be discussed since it belongs largely in the field of endocrinology rather than nutrition Abnormalities of carbohydrate metabolism are usually hormonal rather than nutritional in origin However, changes do occur in starvation (19) and in certain nu tritional disorders associated with malabsorption (See p 123 ) The simplest tests used in evaluating carbohydrate metabolism are determination of glucose excretion in the urine and estimation of glucose concentration in the blood during fasting and at intervals after the administration of a large dose of glucose, the glucose tolerance test Normal ·LIPID NUTRITION UNTIL recently, few attempts have been made to evaluate lipid nutrition aside from estimation of the extent of body fat stores in relation to obesity Fats have been considered largely as a source of calories, as carriers of the fat soluble vitamins and as contributors to the palatability and satiety value of diets There has been considerable but sporadic interest in cholesterol metabolism and hypercholesterolemic states A few studies have been carried out relative to the essentiality for man of certain polyunsaturated fatty acids which are known to be required in the diet of many animal species (51a) In the past few years, however, evidence has accumulated that suggests a relationship between dietary fat, serum lipid levels and the development of atherosclerosis As a result, extensive research in lipid metabolism has been stimulated and a new area of nutritional diagnosis is being developed Lipids comprise a wide variety of chemical compounds the most important of wbich are fatty acids, triglycerides (neutral fat) phospholipids and sterols Triglycerides consist of three fatty acids combined with glycerol There are many types of phospholipids and there are two important sterols cholesterol found in animal tissues and sitosterol in plants Fatty acids differ in chain length (number of carbon atoms) and in degree of unsaturation (number of double bonds) The polyunsaturated fatty acids, linoleic linolenic and arachidonic constitute the essential fatty acids for 53 ·52 NUTRITIONAL DIAGNOSIS is abnormally rapid in hyperthyroidism and abnormally slow in hypothyroidisin, hypopituitarism and adrenal insufficiency The glucose tolerance test is of diabetic type in hyperthyroidism and m hyperfunction of the pitui tary gland and adrenal cortex A flat glucose tolerance test is found in hypothyroidism, hypopituitarism and hypo function of the adrenal cortex An excessive fall in blood sugar after a meal, especially one high in sugar, is observed not infrequently in persons who are otherwise normal This functional hypoglycemia may be due to the same mechanism as that which appears to be operative in disease of the pituitary or adrenal gland namely, failure of the liver to respond with an increased Output of glucose until the blood sugar concentration has decreased to levels lower than normal ·LIPD NUTRITION 55 viduals and increases with age, but neither the normal nor optimal level is known In this country, Stare (51) has reported mean cholesterol levels in men and women aged 40-45 years to be 240 and 225 mg per 100 ml respectively There is some evidence that suggests that these levels may be higher than desirable Sixty per cent or more of the cholesterol in blood is esterified, the remainder being present in free form It is thought that esterification occurs preferentially with unsaturated fatty acids All of the lipids in blood are transported in combinatron with protein, cholesterol, phospholipid and tnglycer. ide with globulin, unestenfied fatty acids with albumın Lipoproteins have been studied with several techniques to effect separation, eg, by electrophoresis ultracentrifugation and Cohn fractionation Accordingly, the major fractions have been designated variously leading to confusion in terminology (51b) When lipoproteins are separated by ultracentrifugation the very low density Lipo proteins with Svedberg flotation (Se) unit values of 10 to 400 correspond in general to the "alpha" lipoproteins separated electrophoretically, lipoproteins of low density, Se values of 0 to 10 correspond to the "beta" lipoproteins, while the high density lipoproteins include "alpha," lipoproteins The albumin unesterfied fatty acid complex is of still higher density Chylomicrons which are present only when large amounts of absorbed fat has entered the blood have extremely low density, S, value about 40 000 units Both high and low density lipoproteins contain protein triglycende, cholesterol and phospholipid but in varying proportions It is possible to measure the several moieties which make up the various groups of lipoproteins including their constituent fatty acids Methods are difficult, however and applicable largely in research rather in general diagnosis ·54 NUTRITIONAL DIAGNOSIS animals Presumably they will be found to be essential for man but this has not been demonstrated unequivocally The optimal level of fat in the diet is not known and since fat may be formed from protein or carbohydrate, no requirement can be formulated Recent evidence suggests that both the amount and type of fat in the diet have an important effect on serum lipid levels and that lipid levels in turn may have an influence on the development of atherosclerosis (51, 52) Diets high in fat increase serum cholesterol and other lipid levels of other conditions re main the same With diets of comparable fat content, serum cholesterol concentrations are lower when the dietary fat contains large amounts of unsaturated fatty acids than when it is made up largely of saturated fatty acids The polyunsaturated or essential fatty acids may be of particular importance in this situation Thus in evaluating lipid nutrition not only should the total fat intake be ascertained but also the type of fatty acids in cluded in the diet The cholesterol content of the diet does not significantly influence serum cholesterol concentration over a range of intake of 250 to 800 mg daily which corresponds to quan tities present in a wide variety of diets (53) Cholesterol is manufactured in amounts of 15 to 20 gm daily from acetate (54) which in turn can be formed from protein or carbohydrate SERUM LIPID CONCENTRATIONS Plasma contains approximately 300 mg of fatty acids per 100 ml 80 per cent of the fatty acids are present as phospholipids or as simple esters of glycerol (triglycer ides), 15 per cent are esterified with cholesterol and 5 per cent are unesterified (51b) The blood cholesterol level varies widely among population groups and among indı ·LIPID NUTRITION 57 discases associated with hypercholesterolemia such as diabetes mellitus, hypothyroidism and the nephroses Persons who have coronary artery disease have been found to have higher mean levels of serum cholesterol than persons of similar age and sex who have no clinically demonstrable atherosclerosis In spite of the limitations in interpreting scrum cholesterol concentration, this measurement gives as much information relative to the possibility of atherosclerotic complications developing as does any other determination currently available Simple examination of fasting serum for turbidity or milkıness, in conjunction with a cholesterol determination, is also informative (51b) In general, an elevated serum cholesterol level will be associated with an increase in the concentration of low or very low density lipoproteins Marked elevation of cholesterol concentration in clear serum usually reflects an increase in the low density lipoproteins (S. 0 to 10) and the serum often is deep yellow in color due to the carotene carried by this fraction Lactescence of the serum implies an increase in triglycerides and of the lower density (higher Sc) lipoproteins Idropathic hyperlipemia is associated with marked turbidity and the bulk of the triglyceride rich lipoproteins may be chylomicrons Measurement of specific lipoprotein fractions is of assistance in evaluating lipid metabolism in a number of diseases (51b) Xanthomatous biliary cirrhosis may be accompanied by very low concentrations of high density lipoproteins even though serum cholesterol may be abnormally high In untreated diabetic acidosis and glycogen storage disease, the low density lipoproteins are increased In the nephrotic syndrome, the concentration of very low density lipoproteins is often elevated There is a difference in lipoprotein concentrations between men and women ·56 NUTRITIONAL DIAGNOSIS Little is known about the specific functions of the lipo proteins or relationships of one class to another Fred erickson (51b) has stated It appears that the unifying hypothesis of a single parent molecule, such as the chy lomicron, which would simply be shorn of more and more of its triglyceride to become lipoproteins of successively decreasing size and greater density is not tenable for the whole lipoprotein spectrum although it may be true in part Studies of the mechanism by which blood is cleared of fat indicate that a lipoprotein lipase probably catalyzes the hydrolysis of triglyceride and is responsible for the disappearance of chylomicrons and very low density lipo proteins This enzyme has been isolated from the heart and from adipose tissue It appears to be identical with the clearing factor found in blood after the injection of heparin (515) There is evidence that the unesterified fatty acid frac tion of plasma is of considerable significance, presumably it is in this form that fat is transported from depots to other tissues for utılızation In view of the complexaties of lipid metabolism it is obvious that evaluation of lipid nutrition will be no easy task A relatively simple biochemical measurement, that of serum cholesterol, has been widely studied in recent years particularly with reference to atherosclerosis The current status of knowledge of relationships between dietary fat, serum lipid levels and atherosclerosis has been summarized in several recent reviews (51, 52) Determination of serum cholesterol concentration is of value in assessment of lipid nutrition although the normal or ideal level is unknown and there are wide variations among individuals and even in the same person at different times The incidence of atherosclerosis is increased in ·LIPID NUTRITIOV 59 and enzymatic breakdown to fatty acids is unimpaired It has been postulated that the malabsorption may be due to a defective phosphorylating mechanism as a result of deficiency of one or more vitamins of the B compler Since administration of folic acid and vitamin B. often improve absorption, these vitamins may be involved Another condition associated with malabsorption of fat is pancreatic fibrosis In this situation, a lessened amount of pancreatic lipase is responsible for failure to hydrolyze fat The best method for measuring fat absorption is the metabolic balance study in which both dietary intake and fecal excretion of fat are determined in clinical diagnosis, this is seldom feasible Gross and microscopic examination of the stool for fat gives some information of the previous and current dietary intake of fat can be estimated but this is only a rough qualitative test at best A procedure that has been widely used in studying fat absorption is the vitamin A tolerance test A large dose of vitamin A in an oily medium is administered for erample 5000 IU per kilogram of body weight, and blood levels are determined before and at 6 9 and 12 hours after the test dose In normal subjects the concentration of vitamin A in blood increases marhedly usually five fold or more in patients with malabsorption of fat, only small and delay ed increases in serum vitamin A are observed (See Table 6 ) The administration of Lipiodol with measurement of 10dine excretion in the urine has been suggested as a procedure for estimation of fat absorption but this test has not proved satisfactory Estimation of the degree of lipemia after ingestion of a test meal of fat has been used to some extent in studying fat absorption Since chemical analysis of lipids presents serious technical difficulties, determination of plasma tur- ·58 NUTRITIONAL DIAGNOSIS In the age group 15 to 65 the male has higher concentra tions of all major low density lipoproteins than the female Gofman (55) has shown that in patients who have had a myocardial infarction the levels of low density lipopro teins, especially S, 12-400 classes, are elevated Other measurements of lipid nutrition include chylomi cron counts and determination of phospholipid concen tration in blood and of the phospholipid cholesterol ratio Accurate chylomicron counts are difficult to obtain and the interpretation of findings is uncertain Elevated or prolonged chylomicronemia has been suggested as a pos sible contributing factor to the development of ather osclerosis but data are few The normal phospholipid concentration in serum is in the neighborhood of 220 mg per 100 ml and increases with age as does cholesterol concentration A decrease in the phospholipid cholesterol ratio has been considered an undesirable finding The con centration of polyunsaturated fatty acids in serum may be measured but methods are difficult and as yet no standards of normalcy are available It is anticipated that the great attention currently being directed to lipid metabolism will evolve new tests and more accurate methods of evalu ating lipid nutrition in the near future ABSORPTION OF LIPIDS Abnormalities in fat absorption present another problem frequently encountered in clinical nutrition Bile salts have an important role in the emulsifying system which affects absorption of lipids Impaired absorption of fat is observed when bile is absent from the intestinal tract, as in obstructive jaundice, although the hydrolysis of fat to fatty acids and glycerol by pancreatic lipase proceeds normally Fat is poorly absorbed in sprue idiopathic stea torrhea and the celiac syndrome although bile is available ·LIPID NUTRITION 61 manner as described for triolein (56) Most patients who have diseases of the pancreas will have significant impairment of absorption of neutral fat and normal absorption of fatty acid Subtotal gastric resection has been found to result in impaired neutral fat absorption in approximately half of the patents studied (56) KETOSIS Ketosis should be mentioned briefly since it is occasionally a nutritional problem Fat is used for energy continuously to some extent, but when there is a shortage of carbohydrate, fat is necded for this purpose in increased amounts Fat is degraded by rapid fragmentation of long chain fatty acids to form 2-carbon and occasionally 4- carbon units Two-carbon units may enter the tricarboxylic acid cycle, may be synthesized to fatty acids or cholesterol, or may condense to form aceto-acetic acid Aceto-acetic acid may be used in the tissues but is not broken down in the liver The formation of this compound is greatly increased in diabetes mellitus and in starvation When the concentration of aceto-acetic acid in the blood reaches 20 mg per 100 ml ketonuria results Some of the aceto-acetic acid is converted to B hydroxy butyric acid and acetone Accumulation of these substances results in acidosis Diagnosis of ketosis is relatively easy as simple tests are available for measurement of ketone bodies in urine and in blood LIPIDS AND LIVER DISEASE The normal liver contains about 4 per cent fat, the majority of which is phospholipid, the remainder being glycendes and cholesterol In a number of pathologic conditions lipids accumulate in the liver cells and this accumulation is often followed by fibrosis and curthosis ·60 NUTRITIONAL DIAGNOSIS bidity or chylomicron counts have been advocated to measure lipemia The latter method is unsatisfactory due to the many variables that influence findings Estimation of plasma turbidity is a simple and informative test which merits further investigation Recently, lipids labelled with [131 have become available for studies of intestinal absorption (56, 57) Triolein and oleic acid labelled with ["i are proving most useful in investigating malabsorption syndromes and in differen tiating between impairment of digestion and impairment of absorption of fat A test meal of 1191 triolein is adminis tered in the fasting state and the radioactivity of blood samples is measured at the 4th, 5th and 6th hours there after (56) The radioactivity of the total stool passed during the 48 hour period after the meal. may be measured also The test meal consist of 25 uc [131 triolein 05 cc peanut oil per kg body weight, an equal amount of water, 2 cc of Tween 80® and 20 gm of barium sulfate The last ingredient is needed to permit checking the emptying time of the stomach which would influence findings of delayed Fecal excretion correlates well with fat balance studies (58) [131 levels in whole blood at the 4th, 5th and 6th hours are indicative of absorption in most in stances Normal individuals gener excrete less than 2% of the administered dose of radioacivity in the stools in the 48 hour collection Patients with sprue and celiac disease will have a flat blood curve and high radioactivity in the feces Abnormalities of fat digestion may be differentiated from those of absorption by administration of a test meal of 11s1-labeled oleic acid in addition to the test meal with 1131-Jabeled trolein Oleic acid 25 pc is given in a gelatine capsule together with three capsules of barium sulfate and radioactivity in blood determined in the same ·MINERAL NUTRITION Most of the 14 minerals which appear to be essential in human nutrition are widely distributed in foods and for many of them there is little danger that dietary deficiency will occur in a number of pathologic states, however, abnormalities of mineral nutrition develop which require diagnosis and therapy The essential minerals are sodium potassium chlorine calcium, phosphorus sulfur, magnesium, iron copper, 1odine, maganese, cobalt, zinc and molybdenum Until recently, mineral metabolism has been a somewhat neglected field of study, yet min erals, like vitamins have many vital physiologic functions including important roles in enzyme systems WATER AND ELECTROLYTES Disturbances of water and electrolyte metabolism are extremely common and important in clinical medicine Our understanding in this field has been increased greatly through the use of isotopic techniques and by investiga tions of the role of the endocrine glands in water and electrolyte metabolism The method of flame photometry for estimation of sodium and potassium likewise has made a distinct contribution to clinical investigation Only a brief résumé of knowledge in this field, with particular emphasis on nutritional aspects, can be undertaken in this discussion A recent symposium gives many interesting details of some of the newer concepts and their application to medical problems (61) For centuries water has been recognized as indispen- 63 ·62 NUTRITIONAL DIAGNOSIS Fatty livers have been produced in experimental animals by diets high in fat and by diets low in protein and low in fat Deficiency of choline or methionine appears to be related to the accumulation of lipid in these situations (60) Abundant evidence suggests that cirrhosis of the liver in man is often due to dietary deficiency Adminis tration of choline has been shown to result in a decrease in liver fat in fatty alcoholic cirrhosis (39), both choline and methionine have been found to increase the rate of phospholipid turnover (40) The value of diets high in protein in the prevention and treatment of experimental cirrhosis is well documented, evidence strongly suggests that this is the case in man LIPIDS AND GALLBLADDER DISEASE Lipids have long been implicated in disease of the gall bladder particularly in the pathogenesis of cholehthiasis Gallbladder disease occurs with increased frequency in hypercholesterolemic states There is little precise infor mation however, on the metabolic abnormalities which are responsible for the formation of gallstones Bile con tains cholesterol and cholesterol is metabolized to bile acids The gallbladder wall can absorb lipids and choles terol deposits are common in the wall and lumen of the gallbladder, increasing with advancing age Aside from these few facts, little is known of the role of cholesterol in the production of cholelithiasis The current extensive investigation of lipid metabolism should elucidate this problem ·MINERAL NUTRITION 65 organ in the hypothalamus Perhaps a deficit in volume in some key portion of the body fuds may promote secretion also Painful and disagreeable stimuli increase secretion The normal adult kidney can excrete the catabolites formed in 24 hours in as little as 500 ml of urine In the infant, the ability to concentrate unne is limited, the metabolic rate is higher, more metabolites per unit of body size must be excreted and insensible loss of water from the skin is greater than in the adult As a result, depletion of body water can occur more rapidly and be of more senous consequence The total amount of water in the body comprises about 50 to 55 per cent of total body weight, the volume of extracellular fluid amounts to approximately 23 per cent, the plasma volume to about 5 per cent of body weight. Methods for measuring the fluid content of the body and its compartments consist chiefly of dilution techniques many of which employ radioactive isotopes Details of a number of these procedures and findings in certain disease states are given in a recent report by Moore and associates (61a) Water Depletion The syndrome of water depletion was studied in normal subjects by Black, McCance and Young (62) The initial and most prominent symptom was intense thirst the mouth became dry and there was difficulty in swallowing Weakness oliguria and loss of weight in proportion to water deficit were observed Other findings included a change in temperament, confusion and hallucinations Plasma volume decreased slightly serum sodium increased and serum potassium decreased Severe dehydration resulted in prostration peripheral circulatory collapse, anemia, azotemia and serious electrolyte disturbances ·64 NUTRITIONAL DIAGNOSIS sable and man can live for only short periods without it The daily requirement is about 1 ml for each calorie of food or approximately 25 liters for the normal adult living in a temperate climate This water is supplied approximately as follows 1200 ml as liquids, 1000 ml from the water in solid foods and 300 ml from the water produced by oxidation When water balance is being maintained, the loss is likewise about 25 liters of which approximately 1500 ml is excreted by the kidneys, 500 ml by the skin as insensible perspiration, 500 ml in the expired air and 100 ml in the stool The mınırnal intake of water which will meet requirements during fasting, if activity is limited, is 08 liter daily which represents about 50 per cent of the need The remainder is furnished by oxidation and release of cellular water Water requirement may be increased markedly in conditions associated with profuse sweating, vomiting diarrhea or polyuria Fluid is continually beng exchanged between the varı ous compartments of the body and balance is maintained by a number of regulatory mechanisms Water which is excreted into the intestinal tract each day may amount to as much as 8 liters of which all but 100 înl is reabsorbed under normal conditions Normally, no electrolyte is lost in the expired air or in insensible perspiration and little in the intestinal discharge Accordingly, the kidney is primarily responsible for water and electrolyte excretion and for maintaining the constancy of the body content of these materials Adrenal cortical hormones and the antidiuretic hormone of the pituitary play important roles in the regu latory mechanism (61b) The primary action of the antı diuretic hormone (ADH) is to decrease renal excretion of water by increasing reabsorption from the kidney tubules The stimulus for ADH secretion is an increase in the osmotic pressure of the fluid bathing a receptor ·MINERAL NUTRITION 67 renal ischemia, hypotension and penpheral circulatory failure Oliguria and water retention may follow trauma and perhaps other forms of stress The surgical patient is liable to water retention and intoxication if an ercessive amount of sodium free water is administered It has been suggested that anuric patients metabolize large amounts of fat and that this endogenously produced water increases body water even if external water and electrolyte balance remain constant Some surgical patients likewise metabolize considerable amounts of fat The majority of cases of water intoxication result when ercessive fluids are given parenterally or per rectum, occasionaly from oral intake The clinical symptoms of acute water intoxication, according to Wynn (61c), usually begin suddenly with mental disturbances Strange behavior, loss of attention, confusion, staring aphasia, incoordination and sleepiness are interspersed with periods of violent behavior, shouting delirium and extreme muscular weakness” Subsequently, convulsions and coma are observed In cases of insidious onset, lethargy, prostration, muscle weakness, sleepiness, apathy and disorientation are prominent findings Occasionally there is anorexia, nausea ind vomiting Signs of water intoxication are largely the reverse of those of sodium depletion There is gain in weight, normal tissue turgor and elasticity normal tension of the eyeballs warm moist skin, normal pulse and normal or slightly elevated blood pressure Muscle strength is reduced In coma, plantar reflexes are extensor in type Laboratory findings include reduction of hemoglobin and serum protein concentration reflecting the increase in extracellular fluid and blood volume An increase in red cell volume is indicated by a decrease in mean corpuscular hemoglobin concentration Serum sodium and ·66 NUTRITIONAL DIAGNOSIS Dehydration accompanying disease shows many of these findings in conjunction with the primary abnormali ties of the pathologic state Acute dehydration may result from excessive sweating an increase in pulmonary or renal water loss, from vomiting fistulae or diarrhea The daily loss may amount to as much as 14 liters in sweat or urine and 8 liters from the gastrointestinal tract In such situa tions, total body water is reduced but the percentile charge is not great, an acute loss of 7000 ml may result in only a 5 to 7 per cent decrease in total body water However, severe clinical effects ensue Careful measure ment of changes in body weight is more useful in detect ing the extent of acute water depletion and in following rehydration than the more complicated estimations of body water Determination of the volume of packed erythrocytes, of plasma protein concentration or specific gravity of plasma are of assistance in following the course of dehydrated patients Water Intoxication Water intoxication is a term which has been used in the past to describe a syndrome in which water is retained in the body in excess of electrolytes Severe cases are uncommon but significant dilution of body fluids by excess water is frequently observed and also frequently mis diagnosed Actually there are set eral syndromes to which the above definition might apply, in all of which serum hypotonicity is characteristic These include 1) water retention 2) primary sodsum depletion and 3) symptom less hypotonicity or asymptomatic hyponatremia in which the cause is unknown (61c) Primary water retention will be discussed here Many clinical states may be associated with a reduced ability to excrete water, eg organic renal disease, reflex ·MINERAL NUTRITION 69 carbonate, protein and small amounts of organic acids The pH is regulated in large part by the relative amounts of chloride and bicarbonate The chlorides of the blood constitute about two thirds of the anions, the normal concentration being 104 mEq/1 of serum Recent studies indicate that bone functions as an electrolyte reservoir (6le) Skeletal sodrum, which comprises 46% of the total body sodium, undoubtedly plays a role in the sodium economy of the body since some 6 to 13% of this sodium can be mobilized in the adult in response to various stimuli (610) În animals, a loss of bone sodium has been demonstrated with low sodium diets, in hyperchloremic acidosis, after mercurial diuresis and following adrenalectomy Presumably, similar losses may occur in man under comparable conditions In view of this, total deficits of sodium may be greater than those found by the usual methods of calculation Sodium plays a role either alone or in conjunction with other extracellular ions, in the conduction of nerve umpulses and in muscle contractility (64) Sodium metabolism is associated closely with that of water, although the mechanisms regulating excretion of these substances are not the same These mechanisms maintain the concentration and amount of sodium and water in the body relatively constant within wide ranges of intake Sodium is excreted in the urine sweat and feces urinary excretion being of greatest importance Losses in sweat are dependent upon the environmental temperature humidity and body heat In the unacclimatized person the salt content of sweat may be 2 to 3 gm per liter whereas after acclimatization sweat will contain only about 05 gm per liter Losses of sodium in the stool are small regardless of intake in the absence of dirthea, since the lower small intestine and colon absorb large amounts The ·68 NUTRITIONAL DIAGNOSIS chloride are reduced, serum potassium is low or normal Serum bicarbonate is moderately reduced and blood urea nitrogen is usually low unless anuria has been a feature of the condition The sodium and chloride concentration of the urine may be quite high despite the low serum concentration SODIUM AND CHLORIDE It has been customary to discuss the body requirements of sodium and chloride together In view of current knowledge, it would seem desirable to discuss require ment of sodium separately, as well as in terms of salt The minimum need of sodium is not definitely known but patients have been maintained on diets which furnished 200 to 300 mg daily for long periods without apparent all effects The usual intake of sodium chloride (salt) by adults in the United States is 7 to 15 gm daily, far more than minimum requirement (4a) This large supply will amply fulfill needs except under conditions of profuse sweating or severe diarrhea or in certain endocrine and metabolic disturbances Sodium constitutes the largest fraction of the total base of the blood plasma and extracellular fluids, the normal concentration being 140 mEq/1 The total exchangeable sodium in the body, as determined by dilution techniques using radio-sodium, is about 2500 mEq or 41 mEq/kg of body weight Sodium is associated chiefly with chloride and bicarbonate ions and functions with them to maintain the osmotic pressure and ionic equilibrium of the body fluids and tissues (63) When osmotic equilibrium is disturbed the functional capacity and viability of the cells may be seriously affected Cations in the blood other than sodium are calcium, potassium and magnesium anions include chloride, bi ·MINERAL NUTRITIOV 71 The loss of sodium in association with chronic nephritis and certain types of acidosis, for example, diabetic acidosis, has long been appreciated Excessive retention of sodium is observed in many pathologic conditions including cardiac failure nephritis, nephrosis, cirrhosis of the liver and hyperfunction of the adrenal cortex A primary increase in secretion of aldosterone is observed in certain adrenal tumors while a secondary increase in secretion of this hormone has been demonstrated in the other diseases mentioned above in which sodium retention is common (611) The diagnosis of sodium depletion is dependent on appreciation of the situations in which it is likely to occur as well as on clinical and laboratory findings The syndrome is gradual in onset with weakness, lassitude, apathy, and anorexia as early manifestations (65) Postural faintness and restlessness with anxiety may be observed It is noteworthy that thirst, a prominent finding in water depletion, is absent Nausea, vomiting and muscle cramps are noted as the depletion progresses The patient appears haggard tissue turgor and elasticity are decreased and there is loss of weight The blood pressure falls, the pulse pressure is low the limbs are pale and cold, and the pulse is rapid Peripheral circulatory collapse is the mode of death The concentrations of sodium and chlonde in the serum are decreased and excretion of these substances in the urine is very low or absent, except in Addisons or renal disease Plasma volume is decreased and as a consequence, levels of serum protein and hemoglobin and the volume of pached erythrocytes are increased Blood urea nitrogen is elevated serum potassium may be increased and serum bicarbonate decreased Sodium depletion must be differentiated from other syndromes in which hyponatremia is a finding Causes of ·70 NUTRITIONAL DIAGNOSIS urinary excretion of sodium is controlled principally by the renal tubules which reabsorb sodium according to bodily need, glomerular filtration influences loss to a cer tain extent In the normal adult who ingests an average diet, approximately 100 mEq of sodium is excreted in the urine in 24 hours In view of the magnitude of glomer ular filtration, this means that about 99 6% of the sodium presented to the tubules has been reabsorbed (4) When dietary sodium is markedly restricted for several days, almost no sodium is lost in the urine The regulatory mechanism for tubular reabsorption of sodium is con trolled in large measure by hormones of the adrenal gland Recent evidence suggests that aldosterone, the recently isolated adrenal hormone, has a major role in salt and water homeostasis The activity of aldosterone is an alagous to that of desoxycorticosterone in its effect on renal sodium and potassium excretion but is about 30 times as great According to Bartter (611) secretion of this hormone is controlled by a function of extracellular fluid volume, a function of potassium ions and, less importantly, adrenocorticotropic hormones Sodium Depletion and Retention Sodium metabolism is deranged in many disease states Depletion may occur in subjects receiving diets seriously restricted in sodium, such as those used in the therapy of hypertension or in the control of chronic, extensive edema Sodium deficiency may follow prolonged vomit ing diarrhea, profuse sweating exudation of fluid from burned or otherwise injured areas and profound diuresis particularly when low sodrum drets have been admin istered In adrenal insufficiency large amounts of sodium are lost in the urine and much of the symptomatology of Addison s disease may be attributable to sodium depletion ·MINERAL NUTRITION 73 The prognosis is poor unless these is a response to adequate nutritional intake A number of these patients with chronic disease may have a defect similar to that noted in starvation by Moore and associates (61a) In starvation, total body water erpressed as per cent of actual body weight is normal, or nearly so as a result of the balance between marked reduction in intracellular water and marked increase in extracellular fluid The total erchangeable sodium and chlonde are very high, while total exchangeable potassium is low in relation to weight Low serum sodium and slightly high serum potassium concentration are observed, the depression in serum sodrum representing not dehydra tron but relative overhydration Moore suggests that these changes may be explained on the basis of insufficient available energy Enery is required for exclusion of sodium from the cell and retention of potassium within the cell and for maintenance of isotonicity of extracellular fluid by the renal tubule These mechanisms may break down in the absence of sufficient energy If this explanation is correct and applicable to certain patients with chronic disease and hyponatremia, the fundamental need of this group of patients may be for energy It is obvious from the above that accurate diagnosis of the status of sodium metabolism is not simple and that Teliance cannot be placed on any single clinical sign or laboratory test The whole picture must be carefully evaluated At times, the more complicated techniques for studying body composition must be applied for clear definition of the situation Combined Water and Salt Depletion Combined water and salt depletion is a syndrome commonly encountered in clinical medicine Findings are ·72 NUTRITIONAL DIAGNOSIS hyponatremia other than sodium depletion include deple tion of potassium, primary water retention and, possibly, intracellular hypo osmolarity due to a change in the state of intracellular anions (618) The signs of primary water retention have been described (p 67) while those of po tassium depletion wil be considered subsequently (p 76) Hyponatremia may be observed in many chronic, seri ous illnesses and may develop in the presence of a normal , low, or high total body sodium Clinical assessment of the probable level of body sodium is of primary importance for institution of proper therapy Edelman (61f), from a consideration of data compiled from the literature, sug gested that demonstratable edema is a reliable guide to the quantity of sodium in the body Total body sodium was found to be increased by essentially the same amount in edematous subjects with cardiac, hepatic or renal disease who were hyponatremic as in those who were euna tremic Conversely, when total body sodium was de creased dehydration rather than edema accompanied hyponatremia However findings obtained by Moore and associates (la) in studies of starvation show that total body sodium may be high in the absence of edema This may be true in other hyponatremic states A type of hyponatremia often seen in patients with chronic illness has been designated asymptomatic hypo natremia by Wynn (61c) who has pointed out that this condition is unaffected by treatment with salt and not corrected by water restriction It may possible be due to a primary lowering of intracellular osmotic pressure Patients with asymptomatic hyponatremia have no findings relative to the low level of serum sodium per se They exhubit tissue wasting progressive loss of weight, normal pulse and blood pressure and usually, a decrease in hemoglobin, volume of pached erythrocytes and serum proteins ·MINERAL NUTRITION 75 amount may be harmful if therc is renal damage or adrenal insufficiency Potassium is the principal cation of the cells, the concentration in extracellular fluids amounting to only a small per cent of the intracellular concentration In the normal adult, the average level of potassium in serum is 42 mEq/1 in the cells, 112mEq/1 (66) Total exchangeable potassium has been found to be 47 mEq/kg of body weight in the male, 40 mEq/kg in the female (61a) The important role of potassium in metabolism is indi cated by the close relationship between cell growth and potassium accumulation and cell breakdown and potassium loss Potassium is closely associated with protein and glycogen and functions in the cells in conjunction with phosphate chloride and bicarbonate The excitability of nerve tissue the transmission of nerve impulses and the contractılıty of all types of muscles are influenced pro foundly by potassium concentration Paralysis of striated muscle is observed when the serum concentration is less than 2 to 25 mEq/1 Smooth muscle and cardiac muscle, likewise, are affected by potassium deficiency Potassium is involved in a number of enzyme reactions According to Greisheimer (67) the transport of potassium across cell boundaries against existing ionic concentration gradients seems to be linked with the carbohydrate phosphorylation cycle The kidney is largely responsible for maintaining a balance between the intake and output of potassium in a manner which resembles that for sodium except that during fasting or after tissue damage potassium is released from the cells and excreted in the urine Potassium leaves the cells with nitrogen in the ratio of about 27 mEq potassium per gram of nitrogen Schwartz (68) found that potassium excretion is increased under the following con- ·74 NUTRITIONAL DIAGNOSIS those of both water and salt deficiency anorexia, weak ness, nausea, vomiting, muscle cramps and peripheral circulatory collapse (signs of sodium deficiency), thirst and oliguria (signs of water deficiency) Heat cramps, which occur in persons working in very hot environments, are an example of this syndrome If only water is ingested, the severity of symptoms is increased Hypernatremia Hypernatremia appears to be relatively uncommon as judged by the limited number of publications on this sub ject In a recent review Knowles (61g) cites the follow ing causes 1) deficient intake of water 2) excessive out put of water due to a) solute diuresis of urea or glucose b) uncontrolled diabetes insipidus, c) gastroenteritis or d) hyperventılation, and 3) unclassified Hypernatremia signifies a serum sodium concentration greater than 150 mEq/1 It seems likely that a primary water deficiency precedes and initiates the increase in serum sodium con centration in most instances The condition is found most often in elderly patients in whom water intake has been limited or in subjects undergoing solute diuresis from urea or glucose Unless hypernatremia is severe, there are few or no abnormal symptoms or signs In severe cases, coma and bizarre neurologic findings may be observed POTASSIUM Potassium is abundant in both plant and animal tissues and primary dietary deficiency is not observed However, potassium depletion is encountered frequently in clinical medicine secondary to a number of pathologic states The minimal daily requirement of potassium is not known but presumably is similar to that of sodium Ingestion of excessive amounts of potassium leads to toxicity Normal persons can take 6 gm daily without danger but this ·MINERAL NUTRITION 77 1 to 3 mEq per 100 calories metabolized, usually 20 to 30 mEq per square meter of body surface in 24 hours (69) The clinical features of potassium deficiency are dependent on decreased muscular irritability and disturbances of conduction and contractility of the heart muscle Lassitude and general muscular weakness is followed by flaccid paralysis, lethargy and, at times, coma Decreased tone of the smooth muscles produces gastric and intestinal distention, nausea, vomiting and paralytic ileus Cardiac dilation, hypertension congestive heart failure and cardiac arrest may ensue Weakness of the respiratory muscles may be observed Death may be the result of cardiac or respiratory failure or paralytic ileus The paralysis of muscles, both smooth and skeletal, appears to be due to failure of myoneural conduction The electrocardiogram often shows flat or inverted T-waves, prominent U waves, prolongation of the QT interval and RS T segment depression Estimation of serum concentration of potassium is useful in evaluating the status of potassium nutrition if findings are interpreted in the light of certain basic considerations Serum concentration of potassium reflects changes in serum pH and in concentration of potassium in cells (69) Scribner and Burnell (61h) suggest that potassium deficiency and excess be defined in terms of a ratio (Kr) between the total potassium content and the total potassiun capacity of the body The latter means "the sum total of all anions and other chemical groups outside the extracellular space capable of holding or binding potassium ions Potassium depletion represents a decrease in Kr, i e in the content-capacity ratio potassium excess, an increase in this ratio Interpretation of serum potassium concentration requires consideration of factors which can alter concentration independently of Kr The most ·76 NUTRITIONAL DIAGNOSIS ditions when serum potassium concentration increases, in both acidosis and alkalosis, by administration of desory corticosterone, aldosterone, corticosterone, other corticoids or adrenocorticotropic hormone, or by activation of the adrenal cortex Urine with a high level of sodium is usually high in potassium as well The mercurial diuretics produce alkalosis that may or may not be accompanied by potassium deficit In renal failure with oliguria, or when shock and dehydration are present, potassium may be retained and toxic levels may ensue If urine volume is high, potassium excretion is usually maintained evenin advanced renal insufficiency Moderate amounts of potassium are lost in the stools, about 2 millimoles per day being excreted by healthy in fants (69) In infantile diarrhea, potassium loss in the stools may amount to 17 millimoles per day Potassium Deficiency Potassium deficiency is likely to develop in acidosis and alkalosis and in conditions in which tissues are broken down with resultant loss of potassium in the urine Such conditions include starvation, infections tumors diabetes mellitus and stress situations such as trauma or operative procedures Potassium excretion may be increased by altered renal tubular function in alkalosis Also, potassium deficiency alters renal function so that alhalosis ap pears or persists Potassium deficiency may be induced by administration of diuretics and of adrenal cortical hor- Loss of potassium in gastrointestinal secretions through diarrhea or vomiting may lead to depletion Intravenous alimentation with solutions free of potassium may also result in deficiency The expenditure of potas sium under conditions of parenteral feeding varies from mones ·MINERAL NUTRITIOV 79 preventing serious deficiency from developing Patients with all alosis and hypokalemia, also, develop symptoms rcadıly since alkalosis increases the tendency to transfer potassium from cxtracellular to intracellulır fluids In non diabetic acidosis with potassium deficiency, hypokalemia develops more slowly duc in part to retardation in transfer of potassium into the cells by the acidosis and to higher initial scrum potassium concentration in most instances Hyperkalemia Potassium excess and an increase in serum potassium is less common thin hypokalemia It is encountered most often in advanced renal disease with oliguria or when renal function is impaired by shock or dehydration It is also seen in adrenal insufficiency or it may be due to the injudicious use of potassium salts Clinical findings in hyperkalemia include mental confusion, weakness, numb ness and tingling of the extremities, pallor, cold shin, disturbances in cardiac rhythm and peripheral vascular collapse A flaccid paralysis of skeletal muscle has been observed in advanced renal failure when serum concentration of potassium was high resembling the paralysis seen in potassium deficiency (69) Electrocardiographic changes may appear at serum potassium concentrations above 65 mEq/1 and abnormalities roughly parallel the degree of potassium increase There is alteration and peaking of the T waves and prolongation of the QRS and PR intervals Finally auricular standstill and delay in intraventricular conduction may occur ending ultimately in total arryhthmia and cardiac arrest CALCIUM In spite of extensive investigation of calcium metabo lism the most satisfactory level of calcium intake for growth or for maintenance in adult life is unknown and ·78 NUTRITIONAL DIAGNOSIS notable factor is change in extracellular pH In severe alkalosis, serum potassium concentration may be low with an essentially normal content capacity ratio, i e even if cell potassium is normal Serun concentration is espe cially low when cellular potassium is decreased In alka losis serum potassium concentration is not likely to be high unless renal function is impaired and cell potassium is relatively normal (69) In severe acidosis, serum potassium concentration may be high with a normal Kr Concentration may be either normal or high despite cellular defects In fact, a normal serum potassium concentration in acidosis reflects a mod erate potassium depletion while a low serum concentra tion reflects a profound depletion Scribner and Burnell (61h) point out that water depletion, changes in the size of the extracellular space and changes in renal function do not cause significant changes in serum potassium con centration which do not reflect Kr Accordingly, they state that in the majority of clinical situations, the serum po tassium concentration interpreted in the light of extra cellular pH will reflect Kr accurately and, therefore, the potassium needs of patients Diabetic coma may be used to illustrate the above prin ciples Acıdosis causes an initial hyperkalemia The mag nitude of potassium depletion can be estimated by the severity of the acidosis and the serum potassium concen tration when the initial serum potassium concentration is normal or low initial potassium depletion has been moderate or marked After administration of insulin glycogen is deposited and potassium is drawn into the cells Symptoms of deficiency may develop rapidly with restoration of metabolism if deficits have been marked (69) Appreciation of the magnitude of initial depletion and institution of proper therapy is of great importance in ·MINERAL NUTRITION 81 cent is in ionized form, the remainder being bound to protein and varying with the concentration of serum proteins The ionized fraction is responsible for the prevention of tetany Mechanisms for the maintenance of scrum calcium are complicated and arc dependent upon calcification and decalcification of bonc as well as on dictary calcium (63) The parathyroid hormone and vitamin D have dominant roles but the ser hormones, the kidncy and the acid basc balance of the body are also concerned Relationships between calcium, phosphorus and vitamin D and changes which are observed in richets are discussed under vitamin D nutrition (p 140) Calcium excrction varies widely in normal subjects at any given level of intake Excretion is influenced by the calcium intahe skeletal size acid base balance and “endogenous factors” which include several of the body hormones (70) Calcuum Deficiency There is a real need for the development of procedures for evaluating calcium nutrition and detecting deficiency at any early stage Diagnosis at present is dependent upon the appearance of the characteristic clinical picture of tetany which is manifested by carpopedal spasm and, at times convulsive seizures Laryngospasm may occur particularly in children Paresthesias of the hands feet and lips are common Trousseaus and Chvostek s signs are positive The concentration of calcium in serum decreases to low levels, usually to less than 4 m Eq/1 Tetany is observed frequently in association with nchets and osteomalacia and is encountered occasionally in sprue and other steatortheas "Hunger osteomalacia” which is observed in some subjects during starvation may be due in part to deficiency of calcium as well as of protein ·80 NUTRITIONAL DIAGNOSIS there are no methods available for accurate appraisal of the status of calcium nutrition Calcium serves as a structural component of bones and teeth which contain 99 per cent of the calcium in the body The small portion of calcium in serum and soft tissues exists partly in ionized form and is concerned in neuromuscular excitability, the blood clotting mechanism, and membrane permeability It is known that certain enzymes are activated by calcium At least part of the calcium in the skeleton is available to maintain the level in blood and other tissues when dietary supply is limited The recommended dietary allowances for calcium (Table 3) are based largely on balance studies with their inherent defects and difficulties in interpretation Such studies do not indicate the distribution of calcium in the body or the extent of storage Calcium balance tends to reflect pre vious dietary intake and there is evidence of adaptation to low levels of intake It is known that the ability to utilize calcium from in gested food varies greatly among individuals and that numerous exogenous and endogenous factors influence absorption and excretion Utilization is usually in the neighborhood of 20 to 30 per cent but may be greater in children who are deficient in calcium Absorption is in fluenced by the relative and absolute levels of calcium and phosphorus in the diet ratios between 1 1 and 2 1 being optimal during growth Absorption is facılıtated by normal gastric acidity, enhanced by vitamin D and in creased by protein lactose and citrates in the diet Absorption is decreased by the presence of phytates, oxalates and fatty acids in foods due to the formation of insoluble calcium salts The normal concentration of calcium in the blood is 9 to 11 5 mg per 100 ml (45-60 mEq/l) of which 50 60 per ·MINERAL NUTRITION 81 cent is in jonized form, the remainder bcing bound to protein and varying with the concentration of scrum proteins The ionized fraction is responsible for the prci ention of tetany Mechanisms for the maintenance of scrum calcium are complicated and are dependent upon calcification and decalcification of bone as well as on dietary calcium (63) The parathyroid hormone and vitamin D have dominant roles but the ser hormones, the kidney and the acid base balance of the body are also concerned Relationshups between calcium, phosphorus and vitamin D and changes which are observed in rickets are discussed under vitamin D nutntion (p 140) Calcium excretion vanes widely in normal subjects at any given level of intake Excretion is influenced by the calcium intale, sheletal size, acid base balance and "endogenous factors” which include several of the body hormones (70) Calcium Deficiency There is a real need for the development of procedures for evaluating calcium nutrition and detecting deficiency at any early stage Diagnosis at present is dependent upon the appearance of the characteristic clinical picture of tetany which is manifested by carpopedal spasm and, at times, convulsive seizures Laryngospasm may occur particularly in children Paresthesias of the hands feet and lips are common Trousseau s and Chvosteh s signs are positive The concentration of calcium in serum decreases to low levels usually to less than 4 m Eq/1 Tetany is observed frequently in association with rickets and osteomalacia and is encountered occasionally in sprue and other steatortheas “Hunger osteomalacia” which is observed in some subjects during starvation may be due in part to deficiency of calcium as well as of protein ·80 NUTRITIONAL DIAGNOSIS there are no methods available for accurate appraisal of the status of calcium nutrition Calcium serves as a structural component of bones and teeth which contain 99 per cent of the calcium in the body The small portion of calcium in serum and soft tissues eusts partly in ionized form and is concerned in neuromuscular excitability, the blood clotting mechanism, and membrane permeability It is known that certain enzymes are activated by calcium At least part of the calcrum in the sheleton is available to maintain the level in blood and other tissues when dietary supply is limited The recommended dietary allowances for calcium (Table 3) are based largely on balance studies with their inherent defects and difficulties in interpretation Such studies do not indicate the distribution of calcium in the body or the extent of storage Calcium balance tends to reflect pre vious dietary intake and there is evidence of adaptation to low levels of intake It is known that the ability to utilize calcrum from in gested food varies greatly among individuals and that numerous exogenous and endogenous factors influence absorption and excretion Utilization is usually in the neighborhood of 20 to 30 per cent but may be greater in children who are deficient in calcium Absorption is in fluenced by the relative and absolute levels of calcium and phosphorus in the diet, ratios between 1 1 and 2 1 being optimal during growth Absorption is facılıtated by normal gastric acidity enhanced by vitamin D and increased by protein lactose and citrates in the diet Absorption is decreased by the presence of phytates oxalates and fatty acids in foods due to the formation of insoluble calcium salts The normal concentration of calcium in the blood is 9 to 11 5 mg per 100 ml (45 60 mEq/l) of which 50-60 per ·MINERAL NUTRITION 81 cent is in ionized form, the remainder being bound to protein and varying with the concentration of scrum proteins The ronized fraction is responsible for the prevention of tetany Mechanisms for the maintenance of scrum calcium are complicated and arc dependent upon calcification and decalcification of bonc as well as on dietary calcium (63) The parathyroid hormone and vitamin D have dominant roles but the scr hormones, the kidney and the acid base balance of the body are also concerned Relationships between calcium, phosphorus and vitamin D and changes which are observed in richets are discussed under vitamin D nutrition (p 140) Calcium excretion varies widely in normal subjects at any given level of intake Excretion is influenced by the calcium intake, skeletal size, acid base balance and endogenous factors which include several of the body hormones (70) Calcium Deficiency There is a real need for the development of procedures for evaluating calcium nutrition and detecting deficiency at any early stage Diagnosis at present is dependent upon the appearance of the characteristic clinical picture of tetany which is manifested by carpopedal spasm and, at times, convulsive seizures Laryngospasm may occur particularly in children Paresthesias of the hands, feet and lips are common Trousseaus and Chvosteks signs are positive The concentration of calcium in serum decreases to low levels usually to less than 4 m Eq/1 Tetany is observed frequently in association with rickets and osteomalacia and is encountered occasionally in sprue and other steatortheas Hunger osteomalacia which is observed in some subjects dunng starvation may be due in part to deficiency of calcium as well as of protein ·82 NUTRITIONAL DIAGNOSIS The osteoporosis of aging is considered to represent a failure of bone matrix formation rather than calcium de ficiency Therapy with calcium is not efficacious although administration of sex hormones may be beneficial Hypercalcemia and metastatic calcification of tissue does not occur as a result of excessive dietary intake alone but is dependent on excessive administration of vitamin D or some metabolic abnormality such as hyperparathyroid vism PHOSPHORUS The abundant supply of phosphorus in foods almost precludes the possibility of dietary deficiency occurring in man The daily allowance should probably be about equal to that of calcium for children and for women during pregnancy, perhaps 15 times that of calcium for other adults (4a) Phosphorus is distributed in the body as follows about 80 per cent in bones and teeth, 10 per cent in combination with proteins lipids carbohydrates and other organic compounds in muscles and the remainder throughout the body in organic combination (63) The deposition and release of phosphorus from bones is dependent on the same mechanisms that affect calcium Phosphorus has a vital role in many metabolic processes phosphorus compounds are essential in fat and carbo hydrate metabolism and are involved in muscle contrac tion and in energy transfer systems Phosphorylation is essential for absorption of certain nutrients Phosphates of extracellular fud participate in acid base regulation and phosphate is the chief inorganic ion of intracellular fluid The normal inorganic phosphate concentration in blood is 2 to 45 mg/100 ml (1 2-30 mEq/l) in adults 3 to 5 mg/100 ml (2545 mEq/1) in children Phosphorus metabolism like that of calcium is dis turbed in rickets osteomalacia and diseases of the thyroid ·MIYONAI NUTRMOV and parathyroid glands Thc metabolism of this mincml is also influenced by the stcroid hormones In ricicts, urinary excrction of phosphorus is increased This also occurs in the Fanconi syndrome apparently duc to a renal lesion which presents rcabsorption of phosphorus from the tubules (p 42) In "resistant richets," studies with radioactive phosphorus haic shown phosphonis absorption to be normal Mcchanisms responsible for this syn. drome have not been determined, cndocrinc imbalance, abnormal renal function or metabolic abnormalities have been suggested MAGNESIUM Magnesium is undoubtedly required for growth and maintenance but little is known about the quantitate need in man Diets containing 0.25 to 03 mg of magnesium daily, have maintained adults in balance (71) The body contains over 20 gm of magnesium of which more than half is found in bone in combination with calcium and phosphorus The remainder is present in soft tissues largely within the cells where it functions as a catalyst in a number of enzymatic reactions Magnesium deficiency has been observed in several species of animals, neuromuscular abnormalities and renal damage being prominent findings Deficiency in man is not clearly defined although low levels of serum magnesium have been reported in many pathological conditions Low magnesium concentration has been found in association with muscle twitching and convulsions but may be present without any characteristic symptoms The normal value for serum magnesium varies with the method of determination Flink (71) reports a mean value of 191 + 02 mEq/1 by the molybdıvanadate method and 227 = 0 26 mEq/1 by the titan yellow method Serum magnesium does not always reflect body stores of this ·84 NUTRITIONAL DIAGNOSIS substance just as serum potassium concentration may not be indicative of body content Depletion of body magaesium has been demonstrated in diabetic acidosis Flink and associates (71) reported magnesium deficiency in chronic alcoholism and in cer tain other chronic debilitating illnesses Gross muscle tremor and delirium were common findings, muscular twitching, choreiform and athetoid movements and con vulsions were encountered at times Serum magnesium concentration was low in most instances Administration of a magnesium salt appeared beneficial in a number of subjects who had the above findings Response was dra matic in some instances but required several days in others The authors believe that the major manifestations of magnesium deficiency are related to cellular deficit The pathogenesis of magnesium deficiency needs clarification although deficient intake during prolonged periods of parenteral feeding or in the course of prolonged alcoholic episodes are important factors Aldosterone may have an influence as hypomagnesemia and negative magnesium balance has been found in primary aldosteronism (71b) SULFUR Sulfur is a constituent of all body cells being present in the sulfur containing amino acids of proteins Small amounts of inorganic sulfur are also present in tissues Sulfur is found in certain carbohydrates eg, chondroitin sulfuric acid in cartilage tendons and bone matrix It is a constituent of the sulfatides glutathione insulin biotin and thiamine (63) Little is known about the human requirement of sulfur but it is presumably closely related to the need of sulfur containing amino acids These are discussed in connection with protein metabolism (p 35) ·MINERAL NUTRITION 85 IRON Iron deficiency may be nutritional in origin or result from loss of blood, particularly from chronic licmorrhage Dietary deficiency of iron may be observed during the growth period, especially in infancy and adolescence, and during the reproductive life of the female The newborn infant has a certain amount of stored iron the quantity being related to maternal supply during pregnancy Iron has a number of important functions in the body It is an essential component of the hemin chromoproteins, hemoglobin, myoglobin, the cytochromes, peroxidase and catalase All of thesc play vital roles in the transport and utilization of oxygen for energy requirements (72) Knowledge of certain features of iron metabolism is necessary for estimation of the adequacy of dietary intake and for diagnosis of potential iron deficiency before overt anemia occurs Many factors influence iron absorption and once iron is absorbed, only small quantities are lost from the body (72) Studies with radioactive iron indı cate that absorption of iron salts is dependent on bodily need normal adults absorb only small amounts whereas persons with iron deficiency anemia absorb much larger quantities Moore and Dubach (73) have shown that normal subjects absorb about 10 per cent of iron from foodstuffs During the growth period, absorption appears to be related to requirement and ranges from 8 to 28 per cent An increase in absorption occurs in the latter months of pregnancy presumably due to fetal need It has been postulated that absorption is regulated by an iron containing protein ferrtın, in the intestinal mu cosa According to this theory, iron becomes attached to the iron free form of this protein apoferretin in the mucosal cell to produce ferretin and is subsequently re- ·84 NUTRITIONAL DIAGNOSIS substance just as serum potassium concentration may not be indicative of body content Depletion of body magnesium has been demonstrated in diabetic acidosis Flink and associates (71) reported magnesium deficiency in chronic alcoholism and in cer tain other chronic debilitating illnesses Gross muscle tremor and delirium were common findings, muscular twatching, choreiform and athetoid movements and con vulsions were encountered at times Serum magnesium concentration was low in most instances Administration of a magnesium salt appeared beneficial in a number of subjects who had the above findings Response was dra matic in some instances but required several days in others The authors believe that the major manifestations of magnesium deficiency are related to cellular deficit The pathogenesis of magnesium deficiency needs clarıfication although deficient intake during prolonged periods of parenteral feeding or in the course of prolonged alcoholic episodes are important factors Aldosterone may have an influence as hypomagnesemia and negative magnesium balance has been found in primary aldosteronism (71b) SULFUR Sulfur is a constituent of all body cells being present in the sulfur containing amino acids of proteins Small amounts of inorganic sulfur are also present in tissues Sulfur is found in certain carbohydrates, eg chondroitin sulfuric acid in cartilage, tendons and bone matrix It is a constituent of the sulfatides glutathione, insulin biotin and thiamine (63) Little is known about the human requirement of sulfur but it is presumably closely related to the need of sulfur containing amino acids These are discussed in connection with protein metabolism (p 35) ·MINERAL NUTRITION 85 IRON Iron deficiency may be nutritional in origin or result from loss of blood, particularly from chronic hemorrhage Dietary deficiency of iron may be observed during the growth period, especially in infancy and adolescence, and during the reproductive life of the female The newborn infant has a certain amount of stored iron the quantity being related to maternal supply during pregnancy Iron has a number of important functions in the body It is an essential component of the hemin chromoproteins, hemoglobin, myoglobin, the cytochromes, peroxidase and catalase All of these play vital roles in the transport and utilization of oxygen for energy requircments (72) Knowledge of certain features of iron metabolism is necessary for estimation of the adequacy of dietary intake and for diagnosis of potential iron deficiency before overt anemia occurs Many factors influence iron absorption and once iron is absorbed, only small quantities are lost from the body (72) Studies with radioactive iron indı cate that absorption of iron salts is dependent on bodily need, normal adults absorb only small amounts whereas persons with rron deficiency anemia absorb much larger quantities Moore and Dubach (73) have shown that normal subjects absorb about 10 per cent of iron from foodstuffs During the growth period, absorption ap pears to be related to requirement and ranges from 8 to 28 per cent An increase in absorption occurs in the latter months of pregnancy, presumably due to fetal need It has been postulated that absorption is regulated by an iron containing protein ferritin in the intestinal mu cosa According to this theory, iron becomes attached to the iron free form of this protein, apoferretin in the mucosal cell to produce ferretin and is subsequently re- ·86 NUTRITIONAL DIAGNOSIS leased from ferretin at the blood stream end of the cell Apoferretın is presumably formed in the mucosal cell in response to a decrease in the iron stores of the body Factors other than bodily need which may influence absorption of dietary iron include 1) The chemical nature of the iron in the food, ie, compounds which can be readily converted into ionized form are more available, as is ferrous as compared to ferric iron, 2) the acidity of the gastric juice (of relatively minor importance) and 3) the quantity of phosphates and phytates in the diet which can combine with iron to form insoluble salts Ascorbic acid enhances iron absorption, while adminis tration of hydrochloric acid and antacids are without significant effect These factors must be considered in evaluating the physiologically available iron of the diet Iron is transported in the serum in ferric form attached to a specific beta-1 globulin, siderophılın, also called transferrin The normal level of serum iron ranges from about 80 to 180 ug/100 ml while the maximum iron binding capacity of serum varies from 300 to 360 ug/100 ml Thus the beta l-globulin is normally about 33 per cent saturated with iron Measurement of these levels are important in the diagnosis of iron deficiency as will be discussed subsequently The total amount of iron in the body is about 4 to 5 gm of which approximately 72 per cent is found in hemo globin, slightly over 3 per cent in myoglobin, 02 per cent in parenchymal iron including that present in cytochromes, catalase and peroxidase and the remaining 23 per cent or more as storage iron (72) Iron is stored in two forms, ferritin and hemosiderin in the liver, spleen and bone marrow The extent of the iron stores of the body may be measured by estimating the amount of hemosiderin in bone marrow ·MINERAL NUTRITION 87 Iron crcretion is extremely small, only about 05 to 15 mg daily by all routes including urinc, bilc, swczt, in testines, loss of hair and desquimation of body cells In view of the conser ntion of iron by the body and its continuous rcutılızation, thc dictury requirement is much less than the amount of iron nccded duly in the formation of hemoglobin (26-27 mg ) In the normal adult, rcquircment represents only replacement of the iron lost through ercretion Moorc and Dubach (73) have suggested that the adult male must assimilate 05 to 1 mg of iron daily to maintain balance, the adult female 1 to 2 mg daily Normal women lose an average of 1 mg per day in the menses which accounts for the higher requirement During pregnancy, an average of 27 mg of iron per day is supplied to the fetus, thus increasing maternal need by this amount During growth, there is an additional requirement for the building of new tissues and crpansion of blood volume The increment for growth amounts to 03 to 06 mg daily in the first 20 years of life Since only about 10 per cent of food iron is absorbed, the daily dietary requirement for uron is determined by multiply. ing physiologic need by a factor of 10 Recommended dietary allowances are of this order (Table 3) In pathologic conditions which are associated with blood loss, requirement is greatly increased Gastrointestinal disturbances such as diarrhea achlorhydria or intestinal disease may interfere with absorption and enhance dietary need Consideraable iron may be lost by regular blood donors Iron Deficiency Cartwright and associates (17) have pointed out that iron deficiency may occur in two forms latent and manafest The clinician commonly thinks of microcytic hypo- ·NUTRITIONAL DIAGNOSIS a con chromic anemia as the outstanding feature of iron de ficiency but before anemia occurs, deficiency is relatively far advanced Diagnosis of latent iron deficiency is de pendent upon laboratory procedures which demonstrate a depletion of bodily iron stores, a reduced level of plasma iron, or an increased total iron binding capacity of the plasma Presumably the first change in deficiency is diminution of available iron stores which may be esti mited by the simple method of Rath and Finch (17) The amount of hemosiderin in unstained bone marrow smears is graded 0 to 6 plus, in iron deficiency no hemo siderın or only a trace will be noted The plasma iron level is decreased in all patients with manifest iron deficiency and in most patients with de pleted tissue stores in iron-deficiency anemia centration of less than 50 ug per 100 ml is usually ob served Unfortunately, hypoferremia is not specific for iron deficiency and is encountered in association with infections, even with such mild ones as the common cold Nevertheless, estunation of plasma iron is of value in assessing the adequacy of nutrition for if normal levels are obtained manifest deficiency is ruled out and iron stores have not been exhausted Determination of the iron binding capacity of plasma will differentiate between hypoferremia due to ron de ficiency and that associated with infection In the former total iron binding capacity is increased to over 400 ug/100 ml, in the latter it is decreased In iron deficiency anemia, in view of the hypoferremia and increased iron binding capacity, the saturation of the protein which carries iron is reduced from about 33 to less than 10 per cent The anemia of manifest iron deficiency is character. ized by small cells which are poorly filled with hemo globin The severity of the anemia is usually proportion- ·MINERAL NUTRITIOV ale to the cttent of iron deficiency Deficiency can be suspected by cxamination of a properly prepared and stained blood smear Thic presence of microcyles with pronounced central pallor arc almost specific, only Thalassemia, a rarc condition, nccd bc ruled out This can be donc rcadily by looking for target cells, stippling and nucleated red cells, as well as by physical findings, normal plasma iron, rcduced iron binding capicity and in. creased hemosiderin in the bone marrow The anemia of iron deficiency can be characterized more adequately by estimation of mein compuscular volume (MCV) and mcan corpuscular hemoglobin concentration (MCHC) both of which are rcduccd below the normal values of 82-92 cubic microns and 32-34 per cent respectively In order to obtain reliable figures for MCV and MCHC, the volume of packed red cells, hemoglobin concentration, and erythrocytc counts must be determined with great accuracy With proper tech niques, accuracy of the determination of volume of packed red cells may be about +1 per cent, that of hemoglobu concentration about +2 per cent and of erythrocyte counts +11 per cent In nutrition surveys, determination of hemoglobin in conjunction with stained blood smears can suffice as indicators of iron deficiency anemia, although estimation of the volume of packed erythrocytes gives additional useful information In iron deficiency anemia the clinical findings are those common to all anemias of comparable severity Pallor of the skin and mucous membranes fatigability, weakness giddiness and syncopal attacks are observed frequently Heart failure of the high output type may develop In children there is retardation of growth In some subjects glossitis characterized by papillary atrophy angular stomatitis and dysphagia may be noted In anemia of consider- ·90 NUTRITIONAL DIAGNOSIS able chronicity, the finger nails become flattened and concave giving them a spoon shape to which the term koulonychia has been applied Iron Excess Iron in excessive amounts may be toxic Large amounts of iron are stored after frequent transfusions or intra venous injections of iron In hemochromatosis, which probably represents an inborn metabolic abnormality, iron is absorbed in excessive amounts and massive deposits accumulate in the tissues especially in the liver, pancreas, adrenals and other endocrine glands In this disease, cir rhosis of the liver, pancreatic fibrosis and adrenal insufli ciency are observed Acute toxicity may result from acci dental ingestion of medicinal iron and fatalities have been reported (75) Characteristic symptoms are severe vomit ing often of blood, watery stools which later become turry, and profound shock The pulse is rapid weak or imper ceptible and the blood pressure is low Hypotonia hypo reflexia, dilated pupils, and a semicomatose or comatose state complete the clinical picture Death has occurred in from 4 to 40 hours COPPER The role of copper in human nutrition remains obscure and the requirement is unknown Studies in animals indicate that copper is necessary for the synthesis of the iron porphyrın ring In copper deficiency, the tissue con tent of cytochrome ovdase has been found to be markedly decreased (76) It has been shown that 20 mg of copper daily will maintain balance in an adult The diet usually furnishes 20 to 50 mg and since copper is so widely dis tributed in foods, it seems likely that an adult would suc cumb to caloric inadequacy before severe depletion of ·MINERAL NUTRITION 91 copper could develop (17) The plasma concentration of copper is usually greater than 90 mg/100 ml Although hypocupremia has been found in the newborn and in hepato lenticular degeneration, tissue stores of copper are increased in both conditions Hypocupremia and an increased excretion of copper have been found in the nephrotic syndrome but when an anemia was present, there was no hematopoietic response to copper (17) To date, no definite evidence of copper deficiency in man has been presented Copper has not been shown to be of assistance in the treatment of hypochromic microcytic anemia in adults and only rarely is copper a limiting factor in blood formation in infants COBALT A deficiency of cobalt, per se, has never been recognized in the human subject Positive balance may be maintained with an intake of 5 ug daily Cobalt is essential for the activity of certain enzymes and is an integral part of the vitamin B12 molecule Evaluation of vitamin Biz nutrition is discussed in another section (p 126) IODINE The physiologic importance of iodine rests in its essentiality for the formation of the thyroid hormone which maintains control of energy metabolism through some unknown pathway The human requirement for rodine is about 1 yg per kilogram of body weight daily for basal needs and an additional 2 ug/kg for the maintenance of total metabolic activity The suggested daily allowance for an adult is 0 15 to 030 mg daily (0002 to 0004 mg/kg body weight) (4a) This amount can be supplied by the regular use of iodized salt Iodine is absorbed from the small intestine at an exponential rate which varies with the level of thyroid ac- ·90 NUTRITIONAL DIAGNOSIS able chronicity, the finger nails become flattened and concave giving them a spoon shape to which the term kolonychia has been applied Iron Excess Iron in excessive amounts may be toxic Large amounts of iron are stored after frequent transfusions or intra venous injections of iron In hemochromatosis, which probably represents an inborn metabolic abnormality, iron is absorbed in excessive amounts and assive deposits accumulate in the tissues especially in the liver, pancreas ndrenals and other endocrine glands In this disease cir rhosis of the liver, pancreatic fibrosis and adrenal insuffi ciency are observed Acute toxicity may result from acci dental ingestion of medicinal iron and fatalities have been reported (75) Characteristic symptoms are severe vomit ing often of blood, watery stools which later become tarry, and profound shock The pulse is rapid, weak or imperceptible and the blood pressure is low Hypotonia hypo reflexia, dilated pupils, and a semicomatose or comatose state complete the clinical picture Death has occurred in from 4 to 40 hours COPPER The role of copper in human nutrition remains obscure and the requirement is unknown Studies in animals indicate that copper is necessary for the synthesis of the iron porphyrın ring In copper deficiency the tissue content of cytochrome oxidase has been found to be markedly decreased (76) It has been shown that 20 mg of copper daily will maintain balance in an adult The diet usually furnishes 20 to 50 mg and since copper is so widely distributed in foods, it seems likely that an adult would suc cumb to caloric inadequacy before severe depletion of ·MINERAL NUTRITION 93 thyroid hormone This indicates that iodine is essential for growth, it is also essential for normal fertility and for lactation Diagnosis of endemic goiter is suggested by the presence of an enlarged thyroid gland in a person living in an area where iodine intake is low Other causes of hypertrophy of the thyroid must be ruled out Thyroid enlargement is most commonly seen during puberty and in pregnancy when the need for iodine is increased In goitrogenous areas, the urinary excretion of 10dine is low, ranging from less than 10 to about 65 ug daily, as compared to 72 to 343 ug darly in nongoitrogenous areas The protein bound rodine level in blood is usually within the normal range in persons with endemic goiter The uptake of Iust by the thyroid gland of these individuals is higher than that of euthyroid persons in other areas of the world Hence, this test is not useful in the diagnosis of hyperthyroidism in regions where endemic goiter is prevalent (78) ·92 NUTRITIONAL DIAGNOSIS tivity (77) Iodine is taken up by the thyroid gland which converts it to di iodotyrosine and thyroxine In normal persons, the iodine uptake is proportional to blood con centration Measurement of the uptake of radioactive 1odine is a useful procedure in the diagnosis of thyroid disease, uptake is increased in hyperthyroidism and de creased in hypothyroidism altho numerous factors can in fluence findings The iodine in blood is in two forms, inorganic and protein-bound iodine, the later presumably representing the circulating thyroid hormone The total iodine of whole blood ranges from 3 to 30 ug/100 ml, usually 8 12 ug, while protein bound iodine varies from 3 to 8 mg, mean 56 ug The level of protein bound 10dine is decreased in hypothyroidism and increased in hyperthyroidism and during pregnancy Urinary excretion of iodine is depen dent upon dietary intake the activity of the thyroid gland and probably other factors lodine Deficiency Iodine deficiency leads to the development of endemic goiter In areas of the world where the iodine content of the water, soil and foods grown therein are low, the incidence of endemic goiter is high Goiter can be pro duced by factors other than iodine deficiency Goitrogenic agents have been found in foods, especially in those of the cabbage family and a number of synthetic chemical com pounds have goitrogenic activity In endemic goiter, the thyroid gland may contain less than 1 mg of 1odine whereas the normal thyroid contains 8 to 10 mg In areas where endemic goiter is prevalent, congenital hypothyroidism or cretinism is observed In cretinism growth may be stimulated and normal mental and physical development attained by continuous administration of ·VITAMIN NUTRITION mins in a single prescription crcept in situations of gross dietary inadequacy or in pathologic states requiring pro longed parental feeding On the other hand, it is often essential to furnish, at the same time, cich of the vitamins which function in various stages of a given metabolic process In view of the above, diagnosis of vitamın malnutrition must be considered from the standpoint of individual chemical compounds and not the group as a whole This is truc in spite of the fact that certain of the vitamins, the “B group in particular, are found closely associated in nature and that multiple deficiency is more often encountered than deficiency of a single factor Appreciation of the complexity of deficiency and of the interrelation ships among nutrients is necessary if correct diagnosis is to be achieved Vitamins, or their derivatives, have been shown to function in metabolism in combination with proteins in the promotion of catalysis of certain body processes Most commonly, vitamin derivatives are coenzymes while proteins form the corresponding apo enzymes It seems logical to assume that altered biochemical reactions precede clinical signs of vitamin deficiency If this is the case tests of specific metabolic function should permit diagnosis before overt physical abnormalities make their appearance As yet few tests of metabolic function are available Appropriate experimental matenals such as specimens of tissue, are not easily obtained In the limited studies which have been conducted, metabolic alterations have been found to be quantitative rather than qualitative and suitable norms and variability among individuals around these norms have not been established In addı tion as Snell has indicated, most of the enzymes examined thus far “have not shown readily measurably changes before other more readily observable deficiency symptoms ·VITAMIN NUTRITION GENERAL OBSERVATIONS IN MANY ways it is unfortunate that a number of the chemical substances which are dietary essentials have been grouped together in a single category desig nated vitamins If the entire group of 15 or more vitamins is considered together, the only characteristic that all members have in common is essentiality in small amounts in the diet due to the body s inability to manufacture them from simpler compounds Even this statement is not en tirely true Many animals can synthesize ascorbic acid, and all animal species tested, including man, manufac ture niacın from the amino acid tryptophan In some in stances, synthesis of a vitamin by bacteria in the intes tinal tract may furnish a sufficient amount of a particular vitamın eg, vitamin K, to largely eliminate the necessity of its inclusion in the diet Modern nutritional science has advanced to such an extent that each of the vitamins should be considered separately in terms of its chemical structure, requirement and function in the body While there are close functional interrelationships between many of the vitamins, others are not so related In addition there are as close or closer interrelationships between vitamins and min erals, and between vitamins and amino acids as there are among the vitamins themselves Pathologic conditions which influence the requirement or utilization of one vita min may not affect that of another There is Jittle scien tific justification for the therapeutic use of all of the vita- 94 ·VITAMIN NUTRITION 97 cream), and as thc pro-vitamin, carotenc, which is present in green and yellow vegetables and in fruits Carotene is converted to vitamin A cster presumably in the intestinal wall The availability of carotene in food varies widely, a factor which must be considered in estimating the potential vitamin A value of the diet Since vitamin A is fat soluble, absorption is facilitated by the simultaneous absorption of fat and deficiency may be encountered when absorption of fat is decreased The latter occurs when bile is absent from the intestinal tract, in infectious hepatitis, and in steatortheas, 1 e, sprue, celiac disease, pancreatic fibrosis and idiopathic steatorrhea. Administration of liquid petroleum with meals interferes with absorption of carotene and, to a lesser extent, of vitamin A Vitamin A deficiency may be encountered in diabetes mellitus and hypothyroidism in which diseases conversion of carotene to vitamin A seems to be impaired Since the liver is the chief site of storage of vitamin A, deficiency may be associated with chronic liver disease, particularly advanced curthosis The minimum daily requirement of vitamin A is 20 I U or 6 ug per kilogram of body weight, if supplied by the preformed vitamin and three to five times as much if furnished by dietary carotene Quantities above minimum are needed to provide for significant storage and in animals, for normal reproduction The recommended allowance of the Food and Nutrition Board for vitamin A is 5000 IU daily for an adult receiving a mied diet which supplies two-thirds of the vitamin as carotene (See Table 3) In using the dietary record for evaluating vitamin A nutrition it should be remembered that large amounts of the vitamin may have been stored in the liver and that many months may be required for depletion of these reserves (79) ·96 NUTRITIONAL DIAGNOSIS it appear (17) This last statement may be explained best by presuming that the proper enzymes have not been chosen for study It would not be anticipated that all enzymes dependent on a given vitamin would decrease in activity at the same rate as deficiency progresses Enzymes requiring the highest concentration of coenzyme for activation would be most rapidly affected and hypo function of these enzymes presumably should lead to the earliest clinical signs of deficiency (17) When enzymes unusually sensitive to vitamin deficiency are discovered, may be possible to devise suitable load” tests which will cause the enzymes to work at maximum capacity Resulting metabolites can be measured and findings in experimental and control subjects compared Such tests would obviate the necessity for analysis of tissue samples A few procedures of this type have been proposed rela tive to vitamin B. (119) and thiamine (p 107) It might be anticipated that no single test of specific meta bolic function will suffice in detecting deficiency or ade quacy of a given vitamin under all conditions Minimal daily requirements of some of the vitamins essential to man have been determined, little is known of optimal needs Undoubtedly, numerous factors influence requirement For vitamin requiring bacteria, the optimal intake of a vitamin cannot be determined apart from the total makeup of the ration (17) It seems likely that this may apply to vitamin needs of animals and man Varia tion in requirement may be expected with changing physiologic conditions and in pathologic states VITAMIN A Vitamin A an unsaturated alcohol, is supplied in the diet as the preformed vitamin which is found only in animal tissues (especially liver, egg yolk, butter and ·VITAMIN NUTRITION 99 Acrosis of the skin with hyperkeratinization, also called toad skin or phrynoderma, is probably another manifcstation of vitamin A deficiency The relationship of localized areas of heratosis of the hair follicles or of permanent "goose flesh' to vitamin A deficiency is less well documented Follicular hyperkeratosis is observed in conditrons unassociated with vitamin A deficiency and has not been produced in experimental deficiency in man In animals, comification of the vaginal smcar is noted in vitamin A deficiency and epithelial changes in the urinary tract have been associated with formation of calculi In human subjects, administration of vitamin A has been reported to induce improvement in scnile vaginitis but a role for vitamin A deficiency in formation of renal calculi remains to be demonstrated In infants deficient in vitamin A, heratınızation of the respiratory cplthelium has resulted in blochage of small bronchioles, bronchiectasis and atelectasis At one time these findings were attributed erroneously to infection which led to the mistaken idea that yitamin A was in antı infective vitamin Estimation of the level of carotene and vitamin A in blood serum are of assistance in the diagnosis of deficiency The concentration of carotene reflects recent dietary intake in most instances and ranges from about 75 to 200 ug per 100 ml in well nourished subjects Hypercarotenemia is associated with consumption of large amounts of carotene or with diseases in which conversion of vitamin A to carotene is impaired, such as diabetes mellitus and hypothyroidism The concentration of vitamin A in the plasma ranges from 30 to 50 ug per 100 ml in well nourished children and adults (17) In vitamin A deficiency the concentration is usually below 15-20 ug per 100 ml and, at times, no vitamin A may be detected ·98 NUTRITIONAL DIAGNOSIS The two important metabolic functions of vitamin A in man are the maintenance of normal epithelium and the formation of the retinal pigment, rhodopsin, of which vitamin A is an integral part (80) Rhodopsın is neces sary for vision in dim light when the dark adapted retina is exposed to light, rhodopsin is changed to reti nine, which is vitamin A aldehyde, plus a protein Vita min A is needed for regeneration of rhodopsin since a certain amount is lost in the process of breakdown In certain anımal species, vitamin A has been shown to influence bone growth Also in animals, deficiency of this factor during pregnancy has resulted in congenital malformations in the offspring Vitamin A Deficiency The principal signs of vitamin A deficiency in hunan subjects are night blindness and rerophthalmia (80) Mild degrees of vitamin A deficiency may be determined by measuring the rate of recovery of dark adaptation following exposure to bright light This procedure requires special instrumentation and rigid techniques as there are many sources of error Its usefulness is limited largely to research studies Xerophthalmia which is encountered rarely in the United States, is manifested by decreased lacrimal secre tion, keratinızation of the corneal and conjunctival epi thelium and Bitots spots which are triangular conjunctival thickenings due to accumulations of white, foam like epithelial cells lateral to the cornea Bitots spots must be differentiated from pingueculae and pterygia which are unrelated to vitamin A deficiency When vitamin A deficiency reaches an advanced stage infection of the eye may occur with destruction of the cornea panophthalmits, and blindness ·VITAMIN NUTRITION 93 Acrosis of the skin with hyperkeratinization, also called toad shin or phrynoderma, is probably another manifes. tation of vitamin A deficiency Thc relationship of localized areas of heratosis of the hair follicles or of permanent "goose flesh" to vitamin A deficiency is less well documented Follicular hyperkeratosis is observed in conditrons unassociated with vitamin A deficiency and has not been produced in experimental deficiency in man In animals, comnification of the vaginal smcar is noted in vitamin A deficiency and cpithelial changes in the urinary tract have been associated with formation of calcule In human subjects, administration of vitamin A has been reported to induce improvement in senile vaginitis but a role for vitamin A deficiency in formation of renal calculi remains to be demonstrated In infants deficient in vitamin A, keratinization of the respiratory epithelium has resulted in blochage of small bronchioles bronchiectasis and atelectasis At one time, these findings were attributed erroneously to infection which led to the mistaken idea that vitamin A was an antı infectie vitamin Estimation of the level of carotene and vitamin A in blood serum are of assistance in the diagnosis of deficiency The concentration of carotene reflects recent dietary intake in most instances and ranges from about 75 to 200 ug per 100 ml in well nourished subjects Hypercarotenemia is associated with consumption of large amounts of carotene or with diseases in which conversion of vitamin A to carotene is impaired, such as diabetes mellitus and hypothyroidism The concentration of vitamin A in the plasma ranges from 30 to 50 ug per 100 ml in well nourished children and adults (17) In vitamin A deficiency the concentration is usually below 15-20 ug per 100 ml and at times no vitamin A may be detected ·100 NUTRITIONAL DIAGNOSIS Unfortunately from a diagnostic standpoint, a decrease in concentration of vitamin A in serum occurs in condi tions unassociated with depletion of vitamin A stores of the body Such decreases are observed in a number of febrile illnesses, the level returning to normal following recovery without administration of vitamin A In the absence of such illness, a low plasma level of vitamin A is presumptive evidence of depletion of reserve stores in the liver The absorption of vitamin A may be tested by means of a tolerance test in which blood levels are determined at intervals after oral administration of large doses of the vitamin (p 59) Comparison of absorption following ad mmistration of oily and aqueous preparations of vitamin A may also prove useful Vitamin A is not found in the urine of normal subjects but may be excreted in certain pathologic states, eg, pneumonia, obstructive jaundice or chronic nephritis In the nephrotic syndrome, high concentration of serum vitamin A has been noted following administration of the vitamin due perhaps to impaired metabolism (81) Hypervitaminosis A Since vitamin A which has been absorbed is not er creted under normal conditions it follows that repeated ingestion of large amounts may lead to excessive accu mulation and toxicity A number of instances of hyper vitaminosis A have been reported most of them in chil dren (82) Abnormal findings have included anorexia loss of weight, irritability, low grade fever, pruriginous rash sparseness of hair changes in bone (hyperostoses and periosteal elevations) hepatomegaly, splenomegaly and hypoplastic anemia The concentration of vitamin A in serum is high usually above 100 mg per 100 ml It has ·VITAMIIN NUTRITION 101 been postulated that the syndrome may bc duc to hepatic dysfunction The minimal toric dosc reported is about 75,000 IU daily for a period of six months (82) VITAMIN B COMPLEX The vitamin B compler comprises a number of factors differing widely in chemical structure, most of which have been found to be essential in human nutrition Many of these vitamins are components of one or more coenzymes which function importantly in intermediate metabolism Such roles have been demonstrated for thiamine, riboflavin, niacin, pyridoxine and pantothenic acid It seems likely that the "antı anemic" vitamins, folic acid and vita min B. will be found to act in a similar manner Choline, often considered a member of the B compler, is undoubtedly important in human nutrition but is not an essential dietary constituent as it may be formed in the body from other compounds Presumably man requires biotin, but little is known about the function of this vitamin Inositol has not been shown to be essential in human nutrition Deficiency of vitamins of the B complex is one of the forms of malnutrition encountered frequently in medical practice Since many of the B vitamins have a common distribution in foods, multiple deficiency is observed more often than deficiency of a single compound Since some of these vitamins are closely interrelated in metabolic processes, the clinical signs of deficiency may be sımlar when the dietary supply of any one of several factors is inadequate Hypervitaminosis is not a problem with members of the B group of vitamins because amounts in excess of requirement are excreted in the urine Numerous pathologic states may be precipitating or contributary causes of vitamin B compler deficiency Dis- ·102 NUTRITIONAL DIAGNOSIS cases in which the metabolic rate is above normal, such as hyperthyroidism, febrile states or leukemia, increase the requirement of thiamine and probably also of ribo flavin and niacin although definitive data are not available for the last two vitamins Since these vitamins function in the metabolism of carbohydrate requirement is in creased when diets are high in starch and sugar or when intravenous glucose is used as the sole source of alımen tation It seems likely that need may be increased follow ing severe trauma The B vitamins may be poorly absorbed or lost from the body in diarrheal diseases, inflammatory lesions of the intestinal tract and in congestive heart failure or other conditions associated with edema of the intestinal mu cosa There is evidence that vitamin B complex deficiency per se may cause poor absorption from the intestinal tract Malabsorption is demonstrated by fat glucose and fat tolerance tests and abnormalities in the roentgeno graphic appe irance of the small intestine The changes observed following barium administration consist of loss of the normal herringbone pattern, hypersegmentation und disturbances in motility In diabetes mellitus and cirrhosis of the liver, signs of vitamin B complex deficiency are observed frequently In both conditions vitamin utilization may be defective and in the latter disease anorexia and an inadequate in take of these factors are the usual findings At times, administration of certain antibiotics may lead to vitamin deficiency although under other circumstances antibiotics may spare vitamin requirement (83) The possibility that prolonged antibiotic therapy may induce deficiency must be kept in mind Lesions suggestive of deficiency must be differentiated from similar change due to complicating fungus infections which are not uncommon ·VITAMIN NUTRITION 103 THIAMINE Thiimine, or vitamin B, is a water soluble compound containing the thuazolc and pyrimidine nngs It is readily destroyed by heat and considerablc loss may occur in the preparation of food Although thamıne is widely distributed in nature, nch sources are few, namely, pois, beans, lean porh, peanuts, oatmcal, whole wheat and cnriched flour and bread How ci cr, milk, vegetables and fruit contribute appreciable quantitics to the dict Thiamine requirement is related to caloric intahc, the minimal need being approximately 0 25 to 0 30 mg per 1000 calories The recommended allowance of this vitamin is 05 mg per 1000 calories (Table 3) Tlus large factor of safety scems desirable since bodily stores of thiamıne are not large and may be exhausted rapidly in diseases associated with elevated metabolism and, perhaps, in other stress situations Thiamıne functions in the body as a coenzyme, cocarboxylase, which is thiamine pyrophosphate and possibly also as a coenzyme in combination with lipoic acid, lipothiamide Thiamine coenzymes are important in the decarboxylation of a heto acids such as pyruvic acid Sub stances formed include acetic acid, acetyl phosphate and acetyl coenzyme A, the last being of great importance as it feeds into the tricarborylic acid cycle to provide energy, In thiamine deficiency, pyruvate accumulates in the blood and tissues and there is a change in the lactate pyruvate ratio These findings are useful in the diagnosis of deficiency Thiamine Deficiency The outstanding clinical findings in advanced thiamine deficiency are peripheral neuritis (dry berzberi) and heart disease with edema (wet beriberi) The diagnosis ·102 NUTRITIONAL DIAGNOSIS eases in which the metabolic rate is above normal, such as hyperthyroidism, febrile states or leukemia, increase the requirement of thiamine and probably also of riboflavin and niacın although definitive data are not available for the last two vitamins Since these vitamins function in the metabolism of carbohydrate, requirement is in creased when diets are high in starch and sugar or when intravenous glucose is used as the sole source of alımen tation It seems likely that need may be increased follow ing severe trauma The B vitamins may be poorly absorbed or lost from the body in diarrheal diseases, inflammatory lesions of the intestinal tract and in congestive heart failure or other conditions associated with edema of the intestinal mu cosa There is evidence that vitamin B complex deficiency per se may cause poor absorption from the intestinal tract Malabsorption is demonstrated by flat glucose and fat tolerance tests and abnormalities in the roentgeno graphic appearance of the small intestine The changes observed follow ing barium administration consist of loss of the normal herringbone" pattern, hypersegmentation and disturbances in motility In diabetes mellitus and cirrhosis of the liver, signs of vitamin B complex deficiency are observed frequently In both conditions vitamin utilization may be defective and in the latter disease anorexia and an inadequate in take of these factors are the usual findıngs At times, administration of certain antibiotics may lead to vitamın deficiency although under other circumstances antibiotics may spare vitamin requirement (83) The possibility that prolonged antibiotic therapy may induce deficiency must be hept in mind Lesions suggestive of deficiency must be differentiated from similar change due to complicating fungus infections which are not uncommon ·VITAMIN NUTRITION 105 jects with cirrhosis of the Incr, peripheral neuritis im. proves following thiamine administration In beriberi hcart discasc, palpitation, prccordınl pain and dyspnca on exertion may be noted and cyanosis is common Bradycardın at rest with tachycardia on crcrtion is seen carly, subscquently, tachycardia may bc persistent The pulsc pressure is wide, with a dccrcase in the diastolic pressure and occasionally a slight increase in systolic pressure There is cnlargement of both the right and left sides of the heart, the former predominating Systolic murmurs and, rarely, diastolic murmurs may be heard over any of the valve arcas Gallop rhythm and embryocardia are common Precordial and cpigastric pulsations are observed frequently, the nech veins are dılated and may pulsatc The liver is cnlarged and pulsations may be observed here as well Edema is often mas. sive and there may be transudation into serious cavities Oliguria is a characteristic finding Roentgenographic examination of the heart shows an increase in the transverse diameter and, at times, enlargement of the pulmonary conus Electrocardiographic abnormalities include lowering of QRS complexes, flattening of the T-waves, prolongation of the QT interval and deviations of the S-T segment Occasionally, premature contractions, axis deviation or abnormalities of the P waves may be noted The cardiac failure is of the high output type, circulation time being normal or decreased Venous pressure is elevated In severe cardiac berberi, acute peripheral circulatory collapse and sudden death may occur The diagnosis of thiamine deficiency heart disease is dependent on dietary history elimination of other etiologic factors, the presence of a high output type of cardiac failure, coexistent peripheral neuritis and response to ·104 NUTRITIONAL DIAGNOSIS of thiamine deficiency is not easy, however, particularly in early stages since many findings are nonspecific and common to other pathologie states In experimentally in duced deficiency, early findings include anorexia fatiga bility, apathy, epigastric pain, nausea and vomiting and psychic and emotional disturbances such as irritability, moodiness, vague fears and depression (81) Daum and associates (84b) reported that the most sensitive physio logie undices of an inadequate supply of thiamine were decreases in maximum work output and in mechanıcal efficiency Early signs of polyneuritis are burtung of the soles of the feet and numbness and tingling of the feet and legs The first indication of heart disease may be ab normalities in the electrocardiogram As polyneuritis becomes more severe, hyperesthesia and, later, an, algesia develops beginning distally in the toes and progressing upward Shooting paias in the legs muscle cramps, tenderness of the calves, weakness, a decrease or absence of the Achilles and patellar reflexes and muscle atrophy may be observed A test for neuritis which is widely used in the Orient is inability to rise from the squatting position Complete flaccid paraly sis with foot drop occurs in advanced deficiency Changes in the upper extremity are rarely observed until involvement of the lower extremity has become Ederna may be present even in the absence of heart failure, the explanation for which is unknown The peripheral neuntis of chronic alcoholism is often due to thiamine deficiency It is explicable by the poor dietary intake of thiamine and not by the ingestion of alcohol which actually requires less thiamine for utiliza tion than does glucose Neuntis in subjects with diabetes is only rarely due to thiamine deficiency In some subsevere ·VITAMIN NUTRITION 105 jects with cirrhosis of the Incr, pcrplıcral neuritis improses following thiaminc administration In beriberı hcart discasc, palpitation, precordial pun and dyspnea on exertion may be noted and cyanosis is common Bradycardır at rest with tachycardia on excrtion is seen cariy, subscquently, tachycırda may be persistent The pulse pressure is wide, with a decrease in the diastolic pressure and occasionally a slight increase in systolic pressure There is enlargement of both the right and left sides of the heart, the former predominating Systolic murmurs and, rarely, diastolic murmurs may be heard over any of the valve areas Gallop rhythm and embryocardia are common Precordial and epigastric pulsations are observed frequently, the neck veins are dilated and may pulsate The liver is enlarged and pulsations may be observed here as well Edema is often massive and there may be transudation into serious cavities Oliguria is a characteristic finding Roentgenographic examination of the heart shows an increase in the transverse diameter and, at times, enlargement of the pulmonary conus Electrocardiographic abnormalities include lowering of QRS complexes flattening of the T waves, prolongation of the QT interval and deviations of the S-T segment Occasionally, premature contractions axis deviation or abnormalities of the P may be noted The cardiac failure is of the high output type circulation time being normal or decreased Venous pressure is elevated In severe cardiac beriben acute peripheral circulatory collapse and sudden death may occur The diagnosis of thiamine deficiency heart disease is dependent on dietary history elimination of other etio logic factors the presence of a hugh output type of cardiac failure coeustent peripheral neuntis and response to waves ·106 NUTRITIONAL DIAGNOSIS therapy with thiamine Digitalis is of little value in the treatment of beriberı heart disease On the other hand, administration of thiamine is followed by diuresis and gradual reversal of pathologic changes, the heart size and electrocardiographic findings returning to normal Infantile beriberi occurs in breast fed infants of mothers who have thiamine deficiency It has been observed rarely in the United States and has been studied largely in Japan and other Far Eastern countries (85) The earli est and most important symptoms are anorexia and vomit ing Urine becomes scant the pulse and respiration labile and rapid Cranial nerve involvement is common par ticularly hoarseness due to vocal cord paralysis and ptosis of the eyelid The child may whine in a plaintive man ner and the 'beriberi cry is said to be characteristic Diagnosis is made when acute symptoms supervene such as paroxysms of pain associated with rigidity of the body but not true convulsions Cyanosis, engorgement of the neck veins and a small rapid pulse are frequent findings Death often occurs within twelve to twenty four hours A less common chronic form of the disease has been de scribed which is characterized by obstinate constipation, vomiting unrelated to meals, restlessness at night, enlarge ment of the heart, pallor and weakness Several laboratory tests have been developed which are useful in the diagnosis of thiamine deficiency (17) The urinary excretion of thiamine is linearly related to the intake except at low levels although there is marked individual variation Measurement of thiamine excretion in 24 hours is useful in reflecting dietary supply In order to evaluate the extent of depletion of tissue stores a test dose of thiamine may be given orally or intramuscularly and the excretion in the urine measured for a period of time thereafter Well nourished subjects who are given ·VITAMIN NUTRITION 107 10 mg of thmaminc intramuscularly crcrctc 100 200 PS in the subscqucnt four hours An crcrction of Icss than 50 ug with this test is usually considcrcd cvidence of deficiency In nutrition surveys, determination of cxcrction of thiamine in rndom specimens of urine in relation to ercretion of creatinine may be used for an approximate estimate of the adequacy of thiamine nutrition Estimation of the concentration of thirminc in blood does not appear to be of much valuc in apprusing nutritional status of individuals although it may reflect, to an extent, the intake of population groups (86) The con centration of pyruvic acid in blood riscs as thiamine deficiency becomes evident but cannot be used as a nutritional index since other factors, such as activity and in gestion of glucose, influence blood levels of pyruvic acid The ratio of lactic acid to pyruvic acid in blood was found by Stotz and Bessey (87) to be useful in determining thiamine adequacy Horwitt (88) has proposed determination of a "carbohydrate inder” for detecting early thiamine deficiency In this test glucose, lactic acid and pyruvic acid are measured in blood one hour after giving 18 gm of glucose per kilogram body weight and 5 min utes after a standard exercise test The index is determined from the formula G CI (-) + ( 10P - + where CI is 10 3 cardiac indes, L lactic acid P pyruvic acid and G glucose An index of more than 15 suggests thiamine deficiency Thiamine deficiency appears to be related to several syndromes other than peripheral neuritis and heart disease A type of optic or retrobulbar neuntıs associated with paralysis of extra ocular muscles, occurred in con- ·108 NUTRITIONAL DIAGNOSIS centration camps in World War II and appeared to be due, at least in part, to thiamine deficiency Wernickes encephalopathy, characterized by ophthalmoplegia, nys tagmus, ataxia and mental disturbances is a syndrome due to deficiency of thiamine (89) Thiamine, and other vitamins of the B complex, have proved valuable in the treatment of delirium tremens and other acute alcoholic psychoses The susceptibility of the nervous system to thiamine deficiency may be explained by its dependence on glucose metabolism Intolerance to large doses of thiamine has been reported and is presumably due to simple chemical toxicity, prin cipally through the formation of excessive amounts of acetylcholine and histamine (90) RIBOFLAVIN Riboflavin is a water soluble, yellow pigment with green flourescence which is widely distributed in foods of both plant and animal origin While relatively stable to heat it is destroyed on exposure to light, hence consider able loss can occur in some foods such as milk The mini mal daily requirement appears to be about 06 07 mg in the adult, 04 05 mg in the infant The recommended intake is considerably higher than this 14 to 16 mg for the adult (Table 3), in order to supply adequate tissue reserves Flavoproteins function in a number of important enzyme systems in tissue respiration There is a close relationship between the retention of riboflavin and the retention of protein It seems likely, therefore that abnormalities of riboflavin metabolism may be associated with severe injuries burns hemorrhage and infection Riboflavin deficiency often occurs in association with lack of niacin and signs of an inadequate supply of riboflavın have been confused with those of pellagra ·VITAMIIN NUTRITION 109 Manifestations of riboflavin deficiency have been observed in prolonged fcbrilc illnesses, such as thicumatic fever, tuberculosis and sub-acute bacterial endocarditis, in malignancy, hyperthyroidism, cardiac fulure, diabetes mellitus and diseases of the gastrointestinal tract Dcficiency occurs with greater frequency in older than in younger age groups Ribofların Deficiency Symptoms of nboflavin deficiency are photophobia, buming of the eyes, lacrimation, soreness of the lips and tongue and crachs at the corners of the mouth Charactertistic physical findings are cheilosus, angular stomatitus, glossitis, a seborrheic type of dermatitis and superficial vascularization of the cornea (91) The lips may be swollen, red at the line of closure and denuded, maceration, crusts and fissures are present at the angles of the mouth Common sites of seborrheic dermatitis are the nasolabial and nasomalar folds, the outer canthi of the eyes and the ears Scrotal dermatitis was a frequent finding in experimentally induced riboflavin deficiency (92) The tongue may be magenta in color with papillary atrophy or hypertrophy, and fissures may be present None of these lesions is pathognomonic of riboflavin deficiency although all of them have been induced in human subjects receiving diets inadequate in nboflavin Cheilosis and angular stomatitis have been observed in experi mental niacın deficiency and following the administration of desoxypyridoxine (93) Lesions of the lips may be the result of exposure to weather while angular fissures occur in association with malocclusion and poorly fitting dentures Vascularization of the comeа may be due to trauma or infection and seborrheic dermatitis may be related to lack of vitamin B, or be unassociated with malnutntion ·110 NUTRITIONAL DIAGNOSIS nosis Glossitis is common in deficiency of many of the B com plex vitamins In animals, the ability of the liver to inactivate estradiol is reduced in riboflavin deficiency It has been suggested that a simular change may occur in man In animals, also, riboflavin deficiency during pregnancy has resulted in abortion and in abnormalities of the embryo The rela tionship of riboflavin deficiency to congenital defects in man remains unknown Diagnosis of riboflavin deficiency is dependent on a history of low dietary intake, the presence of several of the lesions mentioned above and, at times, association with some disease which influences riboflavin metabo lism Laboratory studies may be of assistance in drag The concentrations of free riboflavin and flavin mononucleotide in plasma have been found to decrease in many, but not in all, subjects when the intake of ribo flavın is restricted, while plasma flavin dinucleotide and total white blood cell riboflavin show little change (94) The concentration of riboflavin in red blood cells decreases significantly during periods of restricted intake Bessey (94) has suggested that red blood cell contrations below 14 ug/100 ml can be interpreted as meaning a level of intake that of continued, will lead to clinical manifesta tions of deficiency Concentrations above 20 ug/100 ml indicate an adequate riboflavin intake while analysis of riboflavin in plasma is useful in determining nutritional status, it may be that determination of riboflavin in erythrocytes will prove to be a better measure of tissue stores The latter test requires further study Measurement of the urinary excretion of riboflavin is of limited value in assessment of nutritional status (17) An excretion of more than 200 ug of riboflavin in 24 hours is seldom associated with significant tissue depletion, and ·VITAMIN NUTRITIOV an excretion of more than 150 mg per gram of creatinine in a random specimen of urine is usually indicative of tissue saturation (17) However, cxcrctions of this order of magnitude do not necessarily indicate normalcy The output of nboflavin is increased in acute but not in chronic star ation, in dubetes mellitus, in conditions in which nitrogen balance is negative and after the administration of certain antibiotics Physical activity also influences excretion In subjects receiving constant diets, cxcretion following small test doses (less than 2 mg ) has been found to reflect dietary intake Estimation of crcrction for four hours following parenteral administration of 10 mg of riboflavin is a procedure which seems to merit further study in the evaluation of ribofayın nutrition A controlled therapeutic test is valuable in corroborating the diagnosis of riboflavin deficiency, lesions due to an inadequate supply of riboflavin heal rapidly when the vitamin is administered NLACIN Niacın deficiency its classical form, pelagra, is encountered chiefly in population groups in which com furnishes the staple cereal of the diet The association of pellagra with diets high in com has been explained to a large extent by recent research It has been shown that the amino acid tryptophan is converted by the body through a series of chemical reactions to the vitamin niacin (95) One of the proteins of com zein, is known to be low in tryphtophan The low tryptophan and niacin content of com diets accounts in large part for their pellagragenic effect The possibility that com contains some inhibitory factor which influences niacin requirement has not been ruled out completely but if such a ·110 NUTRITIONAL DIAGNOSIS nosis Glossitis is common in deficiency of many of the B com pler vitamins In animals, the ability of the liver to inactivate estradiol is reduced in riboflavin deficiency It has been suggested that a similar change may occur in man In animals, also, riboflavin deficiency during pregnancy has resulted in abortion and in abnormalities of the embryo The rela tionship of riboflavin deficiency to congenital defects in man remains unknown Diagnosis of riboflavin deficiency is dependent on a history of low dietary intake, the presence of several of the lesions mentioned above and, at times, association with some disease which influences riboflavin metabolism Laboratory studies may be of assistance in drag The concentrations of free riboflavin and flayın mononucleotide in plasma have been found to decrease in many but not in all subjects when the intake of ribo flavin is restricted, while plasına flavin dinucleotide and total white blood cell nboflayin show little change (94) The concentration of riboflavin in red blood cells decreases significantly during periods of restricted intake Bessey (94) has suggested that red blood cell contrations below 14 ug/100 ml can be interpreted as meaning a level of intake that, if continued will lead to clinical manifestations of deficiency Concentrations above 20 ug/100 ml indicate an adequate ribofllavin intake While analysis of riboflavin in plasma is useful in determining nutritional status it may be that determination of riboflavin in erythrocytes will prove to be a better measure of tissue stores The latter test requires further study Measurement of the urinary excretion of nboflavin is of limited value in assessment of nutritional status (17) An excretion of more than 200 ug of riboflavin în 24 hours is seldom associated with significant tissue depletion and ·VITAMIN NUTRITIOV 113 nucleotide, and coenzyme II, triphosphopyridine nucleotide These enzymes, which are found in all cells, aro concerned in glycolysis and tissuc respiration Niacin Deficiency Early signs of niacin deficiency arc lassitude, anoreria, mild digestive disturbances, especially "heartburn,” glossitis diarrhea, and psychic and emotional changes such as anxiety, irritability and depression The tongue is sorc, red, often swollen and there is hypertrophy or atrophy of the papıllae Cheilosis, angular stomatitis and seborrheic dermatitis of the nasolabial folds have been observed in experimental niacın deficiency, although the diet contained an adequate amount of riboflavin (37, 96) The occurrence of similar lesions in niacin and nboflavin deficiency attests the close metabolic relationship of these vitamins In severe or prolonged deficiency, characteristic dermatitis extensive inflammation of mucous membranes and marked mental disturbances are observed The dermatitis involves the skin surfaces exposed to sun light or subjected to trauma or untation In classical pellagra, the dermatitis in the early stages resembles sunburn, subsequently, bleb formation, secondary infection and pigmentation occur At times, the skin is so extensively in volved that bullae break and exfoliate leaving large denuded areas similar to those of a ses ere burn The lesions are bilateral symmetrical and clearly demarcated from the normal skin Areas most often involved are the backs of the hands and forearms, anterior surfaces of the feet and lower legs and the nech (Casals necklace) The face may be involved and also the axilla groin, perineum genitalia, elbows knees and the area under the breasts In mild, chronic pellagra, only thickening hyperkeratin- ·112 NUTRITIONAL DIAGNOSIS factor is present, it is of little practical importance (96) There is evidence that some of the niacin in corn is pres ent in bound form which may be unavailable for absorp tion Since tryptophan is a precursor of niacin, it is neces sary to estimate the tryptophan as well as the niacin con tent of diets in determining the adequacy of niacın in take The ratio of conversion of tryptophan to macın compounds is in the neighborhood of 60 to 1 that is, about 10 mg of niacin is formed from 60 mg of dietary tryptophan (97) Pellagra preventive foods include liver, lean meat peanuts potatoes, legumes milk and eggs, the last two foods furnish little niacin but are excellent sources of trpytophan Since niacin is stable to heat, loss in food preparation is minimal The minimum niacin requirement of the adult is about 90 to 120 mg daily including that formed from trypto phan assuming a conversion ratio of 60 to 1 (4a) The requirement of the infant is about 5 mg duly Require ment appears to be related to body size and to caloric intake (96 97) Approximately 44 mg of niacın is needed for every 2000 calories furnished by the diet, but with low caloric intakes not less than 9 mg should be supplied In terms of body weight about 0 15 mg total niacin per kilogram will prevent pellagra Infants have been maintained satisfactorily for several months on purified diets high in tryptophan and free of Whether the body s niacin requirement can be met solely by tryptophan remains unknown Recommended allowances of niacin (Table 3) are about fifty per cent greater than minimum needs calculated on the basis of body weight or caloric intake Niacin functions in the body as a component of two important coenzymes Coenzyme I, diphosphopyridine niacın ·VITAMIIN NUTRITIOV 113 nucleotide, and coenzyme II, triphosphopyrıdıne nuclco. tide These enzymes, which are found in all cells, aro concerned in glycolysis and tissue respiration Niacin Deficiency Early signs of dracın deficiency are lassitude, anorexia, mild digestive disturbances, especially "hcartburn," glossitis diarrhea, and psychic and emotional changes such as anxiety, irritability and depression The tongue is sore, red, often swollen and there is hypertrophy or atrophy of the papillae Cheilosis, angular stomatitis and sebonheic dermatitis of the nasolabial folds have been observed in experimental niacin deficiency, although the diet contained an adequate amount of nboflavin (37, 96) The occurrence of similar lesions in niacin and nboflavin deficiency attests the close metabolic relationship of these vitamins In severe or prolonged deficiency, characterstic dermatitis extensive inflammation of mucous membranes and marked mental disturbances are observed The dermatitis involves the skin surfaces exposed to sun light or subjected to trauma or irritation in classical pellagra, the dermatitis in the early stages resembles sunbum, subsequently, bleb formation secondary infection and pigmentation occur At times the skin is so extensively involved that bullae break and exfoliate leaving large de- Duded areas similar to those of a severe burn The lesions are bilateral symmetrical and clearly demarcated from the normal skin Areas most often involved are the backs of the hands and forearms anterior surfaces of the feet and lower legs and the neck (Casals necklace) The face may be involved and also the axılla, grom perineum genitalia, elbows knees and the area under the breasts In mild chronic pellagra, only thickening, hyperkeratin- ·112 NUTRITIONAL DIAGNOSIS factor is present, it is of little practical importance (96) There is evidence that some of the niacin in com is pres ent in bound form which may be unavailable for absorp tion Since tryptophan is a precursor of niacin, it is neces sary to estimate the tryptophan as well as the niacin con tent of diets in determining the adequacy of niacin in take The ratio of conversion of tryptophan to niacın compounds is in the neighborhood of 60 to 1, that is, about 10 mg of niacın is formed from 60 mg of dietary tryptophan (97) Pellagra preventive foods include liver, lean meat peanuts potatoes legumes, milk and eggs, the last two foods furnish little niacın but are excellent sources of trpytophan Since niacin is stable to heat, loss in food preparation is minimal The minimum niacin requirement of the adult is about 90 to 120 mg daily including that formed from trypto phan assuming a conversion ratio of 60 to 1 (4a) The requirement of the infant is about 5 mg duly Require ment appears to be related to body size and to caloric intake (96 97) Approximately 44 mg of niacin is needed for every 2000 calories furnished by the diet, but with low caloric intakes not less than 9 mg should be supplied In terms of body weight about 0 15 mg total niacin per kilogram will prevent pellagra Infants have been maintained satisfactorily for several months on purified diets high in tryptophan and free of Whether the bodys niacin requirement can be met solely by tryptophan remains unknown Recom mended allowances of niacin (Table 3) are about fifty per cent greater than minimum needs calculated on the basis of body weight or caloric intake Niacın functions in the body as a component of two im portant coenzymes Coenzyme I, diphosphopyrıdıne niacin ·VITAMIN NUTRITION 115 nacin deficiency appear shortly after this low level is reached Estimation of urinary crcretion of N'Me and pyridonc for 24 hours on a standard dict which fumishes about 100 mg of niacın and 1000 mg of tryptophan gives considerable information relative to niacin nutrition Patients with pellagra ercrete less than 30 mg with this regimen and well nourished subjects 70 to 370 mg (99) This test would seem to ment further study The number of days required for maximum urinary excretion to be attained by subjects receiving the above standard diet, supplemented with 100 mg of niacinamide, has been suggested as a method of estimating the extent of depletion of tissue stores (100) A number of test dose procedures have been suggested for evaluating niacin nutrition (17) One that has been used widely is estimation of urinary excretion of N'Me during a period of four to five hours after administering 500 mg of niacinamide Such tests have not been satisfactory when applied to individuals but have given some information in nutrition sun eys A smaller test dose 100 mg, and at least a 12-hour period of urine collection would be more informative Measurement of excretion of N'Me and pyridone in random urine specimens in relation to creatinine output is being explored as a test for evaluating nutritional status of population groups Measurement of total nicotinic acid or of coenzymes in blood has not proved useful in detecting nacin deficiency Normal concentrations have been found in patients with pellagra Niacın deficiency occurs as a complication of a number of pathologic states in which food intake is restricted or in which there is interference with absorption or utilization of nutrients Subjects with chronic alcoholism cir- ·114 NUTRITIONAL DIAGNOSIS ization, pigmentation and scaling of the skin may be evi dent, particularly over points of pressure Severe inflammation of the entire gastrointestinal tract is found in advanced niacin deficiency glossitis, stoma titis, esophagitis with dysphagia, gastritis, diarrhea, usu ally watery but occasionally containing blood, and proc titis Involvement of other mucous membranes is evi denced by vagınıtıs and urethritis The psychiatric mani festations of severe pellagra include confusion, delusions, hallucinations, disorientation and stupor Deficiency of riboflavin, thiamine and other B com pler vitamins may complicate the clinical picture of en demic pellagra Achlorhydria frequently accompanies niacın deficiency and an anemia, either macrocytic or hypochromic, may be observed The macrocytic anemia responds to folic acid rather than to niacin, while the hypochromic anemia usually represents deficiency of iron A neurologic syndrome consisting of progressive stupor, grasping and sucking reflexes, and cogwheel rigidity of the extremities has been ascribed to acute niacın defici ency This syndrome has been noted in association with febrile illness and prolonged parenteral feeding with glu cose and has been reported to respond to niacin (98) The diagnosis of mild niacin deficiency is not easy in the absence of characteristic dermatitis The glossitis diarrhea and mild mental changes in a subject whose diet has been low in niacin and good protein is highly suggestive Laboratory findings may assist in corroborating the diagnosis Niacin is excreted in the urine largely as N'- Methylnicotinamide (N'Me) and the 6- pyridone of N'Me (pyridone) In subjects maintained on diets low in niacin and tryptophan, excretion of pyridone falls rapidly to less than 1 mg and excretion of N'Me decreases gradually to 05 08 daily (37, 96) Signs of presence of ·VITAMIN NUTRITIOV 117 liter observed in infants who recen ed a proprictory liquid milk formula (103) Tindings included irritability, casy startling, abdominal distention, muscular twitchings and convulsive seizures The clectroencephalogram was abnormal in several instances Recovery followed a change of formula or administration of a large amount of pyridouine Investigation indicated that the sterilization process had destroyed some of the vitamin B. in thus milk preparation There had also been some change in the fatty acid composition of the mixture As a result of this unfortunate episode some knowledge of vitamin B6 requirement was obtained Symptoms developed in infants who received 60 micrograms of vitamins B. per liter of milk while none occurred in infants fed 100 ug of vitaman B per Several attempts have been made to induce vitamin B. deficiency in adults (101) In one experiment, in which two subjects were maintained on 7 vitamin B. deficient diet for three weeks, ercretion of xanthurenic acid after ingestion of tryptophan was increased (101) Xanthurenic acid is an abnormal product of tryptophan metabolism which appears in the urine in vitamin B. deficiency In another experiment one subject was maintained on a vitamin B. deficient diet for 54 days without developing any manifestations of deficiency disease Vilter and associates (105) studied the problem of vitamin B6 deficiency by administering a pyridoxine antagonist desoxypyridoxine to adults some of whom also received a diet low in B complex vitamins Many of the patients became irritable depressed and sometimes somnolent Seborrheic dermatitis developed about the eyes in the nasolabial folds and in the eyebrows and spread to involve the face forehead chin up into the hair and down the neck Occasionally hyperpigmented scaling pellagrous like ·116 NUTRITIONAL DIAGNOSIS rhosis of the liver, prolonged febrile ıllness, diarrheal diseases, diabetes mellitus and neoplasia often develop signs of niacin inadequacy Prolonged parenteral feeding with out niacın supplementation has led to acute pellagra VITAMIN BE Although vitamin B. has been shown only recently to be essential in human nutrition, much information has accumulated as to its important role in metabolic proc esses Vitamin B6 comprises a group of three closely re lated compounds, pyridoxine, pyridoxal and pyridoxa mine Pyridoxal phosphate functions as a coenzyme in a number of reactions involving amino acids, namely, de carboxylation, transamination and desulfuration (101) Through these reactions, materials are provided for the Krebs cycle, which is one of the important energy sources of the body new amino acids are formed and sulfhydryl groups are transferred from one compound to another Vitamin B. has a role in tryptophan metabolism in the conversion of tryptophan to niacın derivatives and func tions in the interconversion of essential fatty acids The exact requirement of vitamin Bhas not been determined but available evidence suggests that 10 to 20 mg daily should be sufficient for an adult, an amount easily pro vided by the average diet in the United States Vitamin B. Deficiency Vitamin B6 deficiency was induced experimentally in two infants both of whom ceased gaining weight while one developed convulsions and the other hypochromic anemia (102) Pyridoxic acid, the main excretory product of pyridoxine metabolism, disappeared from the urine and the ability to convert tryptophan to niacın was lost A syndrome apparently due to vitamin B6 deficiency was ·VITAMIN NUTRITIOV 119 pyrdonne administration In some instances, xanthurenic acid ercrction after tryptophan administration was abnormally high prior to treatment and decrcascd following pyndoune administration Pyridoxinc has been uscd in the treatment of cheilosis, the lesions hcaling in some subjects In seborrheic dermatitis of the secca type, arplication of an ointment containing pyridoxne, but not oral administration of the vitamin, resulted in improvement in lesions in one series of subjects but not in another (101) Although dietary deficiency of pyridoune is an unlikely possibility, it seems logical to anticipate that deficiency may occur in numerous situations in which metabolism is deranged The appearance of some of the clinical manifestations enumerated above should stimulate diagnostic studies to evaluate pyridoxine nutrition Two laboratory procedures are available which measure metabolic functions of pyridoxine Administration of a large dose 100 gm of dl tryptophan stresses the enzyme systems responsible for its degradation Normal subjects will excrete less than 500 mg of xanthurenic acid in the urine in the 24 hours after this test dose while subjects with deficiency will ercrete larger amounts The second procedure is determination of the concentration of blood urea nitrogen after administration of 300 gm of alanine The concentration should return to normal within twelve hours if pyndovine is available in adequate amounts PANTOTHENIC ACID Demonstration that pantothenic acid is essential in animal nutrition and elucidation of its vital role in metabolic processes makes it practically certain that this vitamın is essential in man Pantothenic acid is a constitutent of coenzyme A which occupies a central position ·118 NUTRITIONAL DIAGNOSIS dermatitis developed on the arms and legs Chelosis, glossitis, angular stomatitis, peripheral neuritis and con junctivitis were noted in some subjects These lesions, many of which resemble those of riboflavin, thiamine or niacın deficiency healed only after pyridoxine was ad ministered Lymphopenia occurred regularly in these subjects The excretion of vanthurenic acid in the urine after administration of a test dose of tryptophan was markedly increased but the conversion of tryptophan to niacin was unimpaired Abnormally high levels of blood urea nitrogen were observed after administration of alanıne Several studies indicate that pyridoune metabolism may be altered during pregnancy (106) Lower levels of urea nitrogen in the blood were found in pregnant than in nonpregnant women and concentrations were still further reduced in hyperemesis gravidarum When the amino acid alanıne was administered, blood urea nitrogen concentration remained elevated for more than 12 hours (106a) Similar findings have been reported in vitamin B6 deficiency in animals Pregnant women have been found to excrete abnormally large amounts of xan thurenic acid after administration of tryptophan the ab normality being corrected by pyridoxne (106b) These findings suggest that pyridoxine requirement may be in creased during pregnancy Large amounts of pyridoxine have been shown to prevent or alleviate the peripheral neuntis which may develop during therapy with isoniazid (101) It has been hypothesized that isoniazid may couple with pyridoral to form pyridoxal isoniazid hydrozone thus inactivating enzyme systems dependent on pyridoxal In this way, a conditioned vitamin B. deficiency might be induced The peripheral neuritis which has been observed in some subjects with chronic alcoholism has improved following ·VITAMIN NUTRITION 119 pyridoxine administration In some instances, xanthurenic acid ercretion after tryptophın administration was abnormally hugh prior to treatment and decreased following pyridoune administration Pyridoxine has been used in the treatment of cheilosis, the lesions healing in some subjects In seborrheic dermatitis of the secca type, ap plication of an ointment containing pyridoxine, but not oral administration of the vitamin, resulted in improvement in lesions in one series of subjects but not in another (101) Although dietary deficiency of pyridoxine is an unlikely possibility, it seems logical to anticipate that deficiency may occur in numerous situations in which metabolism is deranged The appearance of some of the clinical manifestations enumerated above should stimulate diagnostic studies to evaluate pyridoxine nutrition Two laboratory procedures are available which measure metabolic functions of pyridoxine Administration of a large dose 100 gm of dl tryptophan stresses the enzyme systems responsible for its degradation Normal subjects will excrete less than 500 mg of ranthurenic acid in the urine in the 24 hours after this test dose, while subjects with deficiency will excrete larger amounts The second procedure is determination of the concentration of blood urea nitro gen after administration of 300 gm of alanine The concentration should return to normal within twelve hours if pyridoxine is available in adequate amounts PANTOTHENIC ACID Demonstration that pantothenic acid is essential in animal nutrition and elucidation of its vital role in metabolic processes makes it practically certain that this vitamin is essential in man Pantothenic acid is a constitutent of coenzyme A which occupies a central position ·120 NUTRITIONAL DIAGNOSIS in metabolism This coenzyme is required for acetylation reactions It functions in the synthesis and degradation of fatty acids and in the entry of fat and carbohydrate into the citric acid cycle Coenzyme A functions in the syn thesis of the porphyrın part of the hemoglobin molecule and in the formation of sterols and steriod hormones The wide distribution of pantothenic acid in foods may explain failure to observe deficiency even on severely re stricted drets Bean and associates (107) investigated the effects of a pantothenic acid free diet, to which the pan tothenic acid antagonist, omegamethyl pantothenic acid was added, in four human subjects A number of phys ical and biochemical disturbances resulted, most of which appeared to be due to pantothenic acid deficiency The subjects became quarrelsome, sullen, petulant and at times, somnolent Paraesthesias of the hands and feet were followed by the appearance of hyperactive reflexes, steppage gait and foot drop Other findings were cardio vascular instability, especially in the upright position, gastrointestinal complaints and repeated infections Bio chemical changes included alterations in acetylation, car bohydrate metabolism serum cholesterol concentration plasma proteins steroid hormone excretion and failure of corticotropin (ACTH) to induce eosinopenia Plasma ascorbic acid concentration decreased while urinary excretion of thiamine and niacin rose during the period of pantothenic acid depletion Individual variations in re sponse to the regimen were large This study strongly suggests the essentiality of panto thenic acid in human nutrition Bean and associates sug gest also that burning feet' a complaint of naturally occurring deficiency states, may be mediated by panto thenic acid deficiency Gopalan (108) has reported relief of the burning foot syndrome with pantothenic acid In ·VITAMIN NUTRITION 121 other studies, pantothenic acid has been reported to in fluence the reaction of human subjects to stress (109) Evaluation of pantothenic acid nutrition must await further investigation and the development and testing of procedures which will indicate metabolic defects due to deficiency of this vitamin FOLIC ACID (FOLACIN - PTEROYLGLUTAMIC ACID) The folic acid group of substances has been shown to be essential for blood formation in man, presumably it is necessary for other important functions as demonstrated in several animal species Macrocytic anemia which responds to folic acid has been observed in infancy, during pregnancy, in sprue and other malabsorption syndromes, in association with poor diets (nutritional macrocytic anemia) and in other less common conditions such as intestinal stricture or following operative procedures in which the intestinal tract was short circuted (110) Folic acid is present in foods in both free and conjugated forms, namely, as pteroylglutamic acid, pteroyltnglutamic acid and pteroylheptaglutamic acid Another member of the folic acid group of substances, folinic acid or citrovorum factor, a formyltetrahydro derivative of folic acid is also found in natural matenals in free and combued form This compound is also formed in the body from folic acid and is excreted in the unne Information concerning the amounts of the vanous folic acid compounds in foods and their biological availability is meagre The best sources appear to be liver, deep green leafy vegetables, other green vegetables kidney muscle meat and whole wheat cereals Darby (111) has reported that diets adequate in other respects furnish about 01 to 04 mg of folic acid compounds daily, poor diets less than 01 mg ·120 NUTRITIONAL DIAGNOSIS in metabolism This coenzyme is required for acetylation reactions It functions in the synthesis and degradation of fatty acids and in the entry of fat and carbohydrate into the citric acid cycle Coenzyme A functions in the syn thesis of the porphyrın part of the hemoglobin molecule and in the formation of sterols and steriod hormones The wide distribution of pantothenic acid in foods may explain failure to observe deficiency even on severely re stricted diets Bean and associates (107) investigated the effects of a pantothenic acid free diet, to which the pan tothenic acid antagonist, omegamethyl pantothenic acid was added, in four human subjects A number of physical and biochemical disturbances resulted, most of which appeared to be due to pantothenic acid deficiency The subjects became quarrelsome sullen petulant and, at times, somnolent Paraesthesias of the hands and feet were followed by the appearance of hyperactive reflexes, steppage gart and foot drop Other findings were cardio vascular instability, especially in the upright position, gastrointestinal complaints and repeated infections Blo chemical changes included alterations in acetylation car bohydrate metabolism, serum cholesterol concentration, plasma proteins steroid hormone excretion, and farlure of corticotropin (ACTH) to induce eosinopenia Plasma ascorbic acid concentration decreased while urinary ex cretion of thiamine and niacin rose during the period of pantothenic acid depletion Individual variations in re sponse to the regimen were large This study strongly suggests the essentiality of panto thenic acid in human nutrition Bean and associates suggest, also, that "burning feet, a complaint of naturally occurring deficiency states may be mediated by panto thenic acid deficiency Gopalan (108) has reported relief of the burning foot syndrome with pantothenic acid In ·VITAN NUTRITION 123 aloblastic bone marrow appear to be prmanly syndromes of folic and deficiency, namely, the macrocytic anemia of pregnancy and the megaloblastic anemia of infancy Nutntional macrocytic anemui und sprue also appear to be due to deficiency of folic acd in some instances while in others, deficiency of Vitamin Bus or both factors may be present. The megaloblastic anemia associated with intestinal stncture or anastomosis and, at times, the macrocytic anemia which occurs in primary liver disease responds to folic acd therapy (113) Cluucal findings common to both Sprue and nutritional macrocytic anemia are the history of an inadequate diet, glossitis, diarrhea, loss of weight and impaired absorption from the gastrointestional tract. In both conditions, a flat glucose intolerance test is a frequent finding Steatorrhea is charactertistic of sprue, the stools contaming large amounts of fatty acids but little neutral fat. Absorp tion of fat and of fat soluble vitamins is impaired This may be demonstrated by administration of fat or of oily preparations of vitamin A and measuring the respective blood levels at intervals thereafter (p 59) Tetany due to hypocalcemia may occur in sprue due to the combination of fatty acids and calcium in the mtestinal tract to form insoluble soaps Recent studies in our laboratory indicate that so-called nutritional macrocytic anemia is, in many instances a malabsorption syndrome glucose, fat and vitamin B12 (even when combined with intrinsic factor) are poorly absorbed from the intestinal tract. Administration of folic acid or atrovonum factor will be followed by hematopoietic response and relief of most of the abnormal findings in sprue and nutrional macrocytic anemia in the majonty of subjects In sprue steatorrhea may persist and in both conditions it is at times necessary to continue therapy indefinitely to prevent re- ·122 NUTRITIONAL DIAGNOSIS Folic acid is synthesized by intestinal bacteria and this source of supply may be important in man, since experimental deficiency has not been induced by diets low in folic acid Evidence from studies in animals, and from therapeutic tests in human macrocytic anemia, suggest that the dietary requirement of folic acid is less than 02 mg daily Folic acid participates in the synthesis of compounds which are used in the formation of nucleoproteins and in transmethylation processes It is concerned with incor poration of the “single carbon unit" into the 2 and 8 positions of the purine ring and the 5 methyl group of thymine and with some of the reactions relating to the for mation of choline, creatine and histidine (112) Folic acid is essential for maintenance of normal hematopoiesis, exerting a hematologic effect in practically all types of human macrocytic anemia, presumably by its function in the formation of thymine and other purines and pyrimi dines Although folic acıd stimulates blood regeneration in pernicious anemia neurologic lesions are unaffected and hematologic relapse occurs unless vitamin B. is ad ministered Folic Acid Deficiency The syndrome of folic acid deficiency is exemplified by the toxic symptoms which develop during administration of aminopterin a folic acid antagonist (110) These symptoms include glossitis, diarrhea gastrointestinal lesions and anemia Toxic manifestations of aminopterin may be reversed by citrovorum factor, if administered promptly but not by folic acid Presumably amınopterın interferes with the conversion of folic acid to its meta bolically active form Several types of human macrocytic anemia with meg- ·VITAMIN NUTRITION 123 or of tionslups of folic acid, vitamin B. and ascorbic acid in patients with megaloblastic anemia have been discussed in detail by Mueller and Will (116) Other metabolic relationships between folic acid and ascorbic acid have been reported Abnormal crcrction of tyrosine metabolites occurs in infants with scurvy and in premature infants given a diet which furnishes large amounts of tyrosine This abnormal excretion may be prevented or relieved by administration of ascorbic acid or by large doses of folic acid (118) There is some evidence that ascorbic acid assists in the conversion of folic acid to citrovorum factor or in the release of citrovorum factor from conjugated form (110, 112) The pathogenesis of nutritional macrocytic anemia and sprue is not clear Neither appears to be due solely to dietary deficiency of folic acid of vitamin B. both factors In some instances, inflammatory disease of the intestinal tract precedes the development of the sprue syndrome and could be responsible for defective absorption but this is not always the case In some subjects with so called nutritional macrocytic anemia, relapse occurs when therapy with folic acid or vitamin B1 is dis continued even though an adequate diet is ingested As noted previously some of these subjects have defects in absorption which may be permanent others may have increased requirement and/or abnormal utilization of the anti anemıc vitamins Some subjects may be deficient in intrinsic factor as are patients with pernicious anemia Laboratory tests have been developed which permit measurement of folic acid concentration in blood and excretion of folic acid and citrovorum factor in the urine In normal subjects receiving ordinary diets average excretion was reported to be 41 and 26 micrograms daily for folic acid and citrovorum factor, respectively (119) ·124 NUTRITIONAL DIAGNOSIS lapse In some instances, vitamin B12 is as effective as folic acid in the therapy of these diseases and occasion ally the two vitamins are more beneficial when given to gether than is either one alone It is interesting to speculate as to the mechanism which leads to folic acid deficiency in the diverse syndromes mentioned above In several animal species, folic acid has been shown to have a role in the reproductive process (113) It was reported recently that administration of a folic acid antagonist, 4 amino pteroylglutamic acid to 12 women who were less than three months pregnant was followed by abortion in ten instances (114) Perhaps there is an increased need of folic acid during pregnancy which is not always met by the dietary intake In such instances, macrocytic anemia might ensue Megaloblastic anemia of infancy presents a compler problem, it appears to be related to deficiency of ascorbic acid as well as of folic acid (112) In the United States this anemia was observed chiefly in infants who received a powdered milk preparation low in vitamin C and has been encountered only rarely since ascorbic acid was added to the formula of this product The anemia occurs in the same age group in which the incidence of scurvy is high Megaloblastic anemia of infancy responds to folic acid or cıtroyorum factor but not to ascorbic acid May and associates (117) produced an anemia in monheys, comparable to that seen in infants by administration of a dret deficient in both ascorbic and folic acid The anemia could be prevented by ascorbic acid alone but responded only partially to treatment with this vitamin Therapy with folic acid was completely satisfactory In South Africa megaloblastic anemia has been encountered in adults with severe scurvy although it is rare (115) This anemia responds to ascorbic acid Interrela ·VITAMIN NUTRITION 127 vitamın Bie is mitritocobalamin An interesting facet of the metabolism of vitamin B12 is its dependence for ab sorption, in the amounts present in the dict, on the intrinsic factor of gastric juice Accordingly, pernicious anemia, which is due to deficiency of vitamin B12, does not develop because of dietary inadequacy but because of an insufficient supply of intrinsic factor It is also of interest that when very large amounts of vitamin B1 are administered orally, absorption occurs in the absence of intrinsic factor (123) In spite of extensive investigation the chemical structure of intrinsic factor is unknown and the mechanism by which it influences absorption has not been elucidated (124) A number of modes of action have been suggested (125) An attractive postulate is that absorption is regulated by a mechanism similar to that for the absorption of iron (126) Intrinsic factor may have functrons other than facilitating absorption of vitamin B. It is known that most of the vitamin B, in blood is bound to the alpha and beta globulin fractions of serum protein, very little is present as the free vatamın Recent studies suggest that intrinsic factor may facilitate the combination of vitamın Biz with a specific protein moiety of serum (127) Miller and associates (128) have found that intrinsic factor concentrates from hog intestine stimulate the uptake of vitamin B.. by liver slices or homogenates and also by homogenates of kidney and intestual mucosa Other studies in our laboratory indicate that there may be a deficiency of the protein factor in serum which combines with vitamin B12 in some patients with macrocytic anemia (129) These observations may lead to a better understanding of the pathologic physiology of pernicious anemia and should assist in the development of new tests useful in diagnosis (p 131) ·126 NUTRITIONAL DIAGNOSIS Some reports indicate that patients with pernicious anemia and sprue excrete smaller amounts of folic acid and citrovorum factor after a test dose of folic acid than do normal subjects (120) Girdwood (120b) has suggested that an excretion of less than 15 mg in 24 hours after an oral test dose of 50 mg of folic acid is indicative of either severe tissue depletion or malabsorption If tissues have been loaded with folic acid prior to testing a small excretion after an oral, as compared to a par enteral, test dose is indicative of malabsorption Few studies of levels of folic acid in blood have been carried out None of these procedures has been studied exten sively in the evaluation of folic acid nutrition VITAMIN B1 (COBALAMIN) The isolation of vitamin B12 and the demonstration that this substance is the antı pernicious anemia factor of liver was an outstanding achievement (121) Search for this factor had been continuous since the late 1920s when Minot and Murphy demonstrated the efficacy of liver in the treatment of pernicious anemia and Castle proposed his theory of the pathogenesis of this disease Castle postulated that an intrinsic factor in gastric juice com bined with an extrinsic factor in food to form the antı pernicious anemia factor of liver Intrinsic factor was found to be absent from the gastric juice of patients with pernicious anemia It is now known that vitamin B12 is not only the antipernicious anemia factor of liver but is also the extrinsic factor of food (122) Vitamin B. like many other members of the B complex, is not a single substance but comprises a group of closely related compounds with similar physiologic activity Vitamin B12 itself is cyanocobalamin while vitamin B D and a which are identical are hy drorycobalamin and ·VITAMIIN NUTRITIOV 123 findings Neurologic abnormalitics arc common, particu. larly parasthesias of thc fingers and tocs and signs of penpheral ncuntis or subacute combined degeneration of the spinal cord Gastrointestinal complaints arc frcqucnt and glossitis is obsen ed in most instances The peripheral blood shows scverc macrocytic anemia, leukopenia with hypersegmentation of the polymorphonuclear cells, and thrombocytopenia Thc bone marrow is hyperplastic and contains large numbers of megaloblasts Excessive erythrocyte destruction is manfested by an increase in the concentration of bilirubin in scrum and high urobilin excretion in the urine Hydrochloric acid is absent from the gastric juice even after stimulation with histamine An abnormality of tyrosine metabolism is demonstrated by the crcretion of certain phenolic compounds in the urine While diagnosis is easy in the classical case of pernicious anemia, difficulties often arise in differentiation from sprue and nutritional macrocytic anemia and even from macrocytic anemia in diseases unrelated to nutritional deficiency Estimation of the concentration of vitamin B12 in serum is of considerable value in diagnosis and in judging the adequacy of therapy (123b, 30) The concentration of vitamin B12 in serum falls to abnormally low levels in pernicious anemia in relapse even before there is significant decrease in erythrocytes in the peripheral blood The level returns to normal with therapy The exact concentration indicative of pernicious anemia is dependent on the method of assay which is employed With a microbiological assay using L Leichmanı as the test organism (131), normal serum contains from 80 to about 500 micromicrograms (ug) per milliliter In pernicious anemia serum concentration is below the normal range and in some instances no vitamin Biz ·128 NUTRITIONAL DIAGNOSIS Vitamin B12 is undoubtedly an essential human nutrient but present information is insufficient to estimate dietary requirement The administration of approximately 1 mi crogram daily, parenterally, will induce remission in pernicious anemia (4a) Presumably, the normal adult needs to absorb an amount no larger than this but the biological availability of vitamin B12 in the diet remains unknown Vitamin B. is required for growth in animals Studies of the effect of vitamin B12 on growth in human subjects have been equivocal (113) It seems likely that under certain conditions of diet and nutrition, vitamin B. may have a growth promoting effect The metabolic functions of vitamin B. are gradually being elucidated (125) This vitamin appears to be in volved in the synthesis of nucleoproteins by way of its participation in the metabolism of purines and Pyrimi dines Promotion of normal hematopoiesis may be er plained on this basis The mode of action in the metab olism of nervous tissue has not been clarified Vitamin B. may have r role in the metabolism of methyl, hydrory methyl and sulfhy drvl groups Vitamin B. Deficiency From the clinical standpoint vitamin B. deficiency is seen primarily in pernicious anemı? Several other types of macrocytic anemia and some neurologic disorders may also be due to deficiency of this vitamin Until recently the diagnosis of pernicious anemia has been dependent entirely on clinical and nonspecific laboratory findings Characteristically the disease occurs in well nourished persons of middle age or beyond who give a history of similar allness in other members of the family Weakness lemon yellow pallor of the skin and signs of cerebral anoxemia or congestive heart failure are often presenting ·VITAMIIN NUTRNOV 123 findings Neurologic abnormalities are common, particu. larly parasthesias of the fingers and tocs and signs of penpheral neuntis or subacute combined degeneration of the spinal cord Gastrointestinal complaints arc frequent and glossitis is obsen cd in most instances The peripheral blood show's scicrc macrocy tic anemia, leukopenia with hypersegmentation of the polymorphonuclear cells, and thrombocytopenia The bone marnow is hyperplastic and contains large numbers of mcgaloblasts Excessive erythrocyte destruction is manfested by an increase in the concentration of bilirubin in scrum and high urobilin excretion in the urinc Hydrochlonc acid is absent from the gastric juice even after stimulation with histamine An abnormality of tyrosine metabolism is demonstrated by the excretion of certain phenolic compounds in the urine While diagnosis is easy in the classical case of pernicious anemia, difficulties often arise in differentiation sprue and nutritional macrocytic anemia and even from macrocytic anemia in diseases unrelated to nutritional deficiency Estimation of the concentration of vitamin But in serum is of considerable value in diagnosis and in judging the adequacy of therapy (1236 30) The concentration of vitamin B. in seruin falls to abnormally low levels in pernicious anemia in relapse even before there is significant decrease in erythrocytes in the peripheral blood The level returns to normal with ther. apy The exact concentration indicative of pernicious anemia is dependent on the method of assay which is employed With a microbiological assay using L Leichmann as the test organism (131) normal senim contains from $0 to about 500 micromicrograms (uug) per milli- Liter In pemicious anemia serum concentration is below the normal range and in some instances no vitamin B. from ·130 NUTRITIONAL DIAGNOSIS can be detected Normal levels of serum vitamin B12 as sayed with the organism Euglena gracılıs range from 350 to 750 micromicrograms per milliliter (132) Low levels of vitamin B12 in blood may be observed in macrocytic anemias other than pemicious anemia that will respond to vitamin B12 The urinary excretion of vitamin B. has been studied by numerous investigators (110) Register and Sarett (119) found an average excretion of 31 millimicrograms (mug) daily in normal subjects on ordinary diets In other studies, somewhat higher values have been reported Excretion tends to be less in patients with pernicious anemia than in normal persons but large variation among individuals prevents this test from being of diag nostic value Studies of urinary excretion following parenteral injection of vitamin B12 indicate, in general, an increase in excretion with increasing dosage (123b) Fol lowing oral administration of vitamin Biz there is little increase in urinary excretion unless very large doses (10 to 30 mg ) are administered Even in these instances excretion is less than anticipated by the concentration of vitamin Biz in serum ie at levels comparable to those obtained with parenteral doses, urinary excretion is much lower A procedure which has been developed for indirectly detecting the presence or absence of intrinsic factor in the gastric juce is the Schilling test (133) which employs vitamin B12 labeled with an isotope of cobalt, Coº Two micrograms of the vitamin (05 microcuries radioactivity) is administered orally followed in 2 hours by a 1000 ug parenteral flushing dose of non labeled vitamin Urine is collected for 24 hours and radioactivity mea. sured In our experience, normal subjects usually excrete more than 6% of the radioactive vitamin with this tech ·VITAMIN NUTRITION 131 nique whereas patients with pernicious anemia excrete less than 2%, the amount often being barely detectable The test is repeated after two or three days using a similar oral dose of Co. vitamin Biz combined with intrinsic factor Excretion of vitamin Biz will increase to normal levels in patients with pernicious anemia In sprue and other macrocytic anemias in which intestinal absorption is defective, excretion remains low even in the presence of intrinsic factor Other tests of absorption of vitamin B12 include neasurement of radioactivity in the feces after oral administration of Coso vitamin B12 (134) and comparison of radioactivity over the liver after oral and parenteral administration of the labeled vitamin (126) Ap in vitro test for intrinsic factor activity which may be applied to gastric juice has been developed in our laboratory (127) It is dependent upon the ability of intrinsic factor to increase the amount of vitamin B12 which will combine with serum proteins A procedure for measuring "serum factor” in blood, ie, the protein moiety which binds vitamin B12 has also been developed Patients with pernicious anemia show low intrinsic factor activity in gastric juice and often low "serum factor" with these procedures In some subjects with so called nutritional macrocytic anemia both tests are extremely low Further study with these procedures may assist in elucidating the etiology of some of the macrocytic anemias and be helpful in their differentiation Vitamin B12 has been found to be effective therapeutically in several types of macrocytic anemia other than pernicious anemia, including that which follows gastrectomy the anemia associated with fish tapeworm infestation, some instances of sprue and nutntional macrocytic anemia and rarely, in macrocytic anemia of chronic liver ·132 NUTRITIONAL DIAGNOSIS disease Following total gastrectomy, vitamin B12 de ficiency develops on the same basis as in pernicious anemia, that is, absence of intrinsic factor Vitamin B.2 deficiency in sprue and nutritional macrocytic anemia may be due to dietary deficiency, impaired absorption, deficiency of serum factor or some other cause as yet unappreciated The macrocytic anemia of fish tapeworm infestation appears to be due to utilization of vitamin Bua by the parasite in the intestınal tract In cirrhosis of the liver, storage of vitamin B12 may be impaired Vitamin B. has been used in the treatment of a num ber of neurologic diseases unassociated with pernicious This vitamin has been reported to relieve the pain of nutritional neuropathy (135) and to be beneficial, at times, in the therapy of peripheral neuritis associated with diabetes mellitus (136) In our experience, vitamin B12 has been efficacious in some instances in treating neuritis that occurred in subjects who had chronic alcoholism and cirrhosis of the liver Whether a deficiency of vitamin B. is present in these conditions remains un known Some abnormality of utilization rather than dietary inadequacy might explain the findings Massive parenteral doses of vitamin B12, 1000 ug daily, have been reported to be followed by cessation of pain in trigeminal neuraliga (137) In this situation, vitamin Bız may be exerting a pharmacologic rather than a physiologic action anemia CHOLINE Little is known about the importance of choline in human nutrition nor are methods available for the diagnosis of choline deficiency In animal experiments ad ministration of diets low in cholae leads to deficiency which is characterized by accumulation of fat in the liver and hemorrhagic lesions of the kidney Choline func- ·VITAMIN NUTRITION 133 tions as an integral part of acctylcholinc, as a sourcc of labile methyl groups and in the formation of phospholipids The dietary requirement of choline in animals or man is uncertain since this compound can be manufac. tured in the body and the need is dependent on other sources of methyl groups in the dict, such as mcthionine or betaine Elvehjem (138) suggested on the basis of animal studies that the humın requirement is probably less than 500 mg daily The average dict contains about 250 to 600 mg of cholinc Choline has been reported to be beneficial in the treatment of fatty liver and cirrhosis in man It is difficult to evaluate such therapy since administration of choline has usually been only one aspect of a regimen which has included a diet high in protein and, in some instances administration of methionine Cornatzer and Cayer (39) found that the administration of a single 100 gm dose of choline resulted in an increase in the rate of phospholipid turnover in subjects in whom fatty infiltration of the liver was demonstrated on initial biopsy When fat was not present in the liver, this effect was not observed Eckhardt and associates (39) in an investigation of subjects with active fatty alcoholic cirrhosis, reported that choline administration was followed by a moderate reduction in liver fat as seen in biopsy specimens The liver cell showed much greater improvement however when a diet adequate in protein was prescribed Choline methionine vitamin Biz and folic acid have been found to be interrelated in the prevention of fatty livers under certain dietary conditions in animals Whether these findings are applicable to man is unknown ·134 NUTRITIONAL DIAGNOSIS BIOTIN It seems most unlikely that spontaneous biotin defi ciency will be observed in human subjects Although biotin is presumably an essential nutrient, not only is it present in food but it is synthesized by the intestinal flora The amounts of biotin excreted in the urine and in the feces are greater than the intake Current knowledge of the metabolism of biotin has been reviewed by Wright (140) Brotin is the antı egg white injury factor, raw egg white contains avidin which combines with biotin making it unavailable to the body Sydenstrıcker and associates (141) produced experimental human deficiency by feeding large amounts of raw egg-white Manifestations in cluded anorexia, muscle pains, and dry scaly dermatitis INOSITOL Little is known of the role of inositol in the nutrition of animals or man Inositol has been administered in conjunction with other agents, in the therapy of several path ologic states for example, chronic liver disease and muscular dystrophy, on postulates which have little factual support The value of inositol in such situations remains unproved ASCORBIC ACID Scurvy was described with accuracy several centuries ago and satisfactory treatment was devised long before ascorbic acid was isolated Only recently however has a role for ascorbic acid in conditions other than scurvy been suggested Extensive investigation has indicated the many biologic functions of this vitamin but its chemical action in metabolic processes remains unclear In evaluating dietary intake of ascorbic acid it should be remembered that this water-soluble vitamin is easily ·VITAMIN NUTRITION 136 suffice (4b 4c) oudized and that loss in the stornge and preparation of food may be great Thic vilamin may be destroycd in the upper intestinal tract in subjects who hasc achlorhy dna or who hric rocci ed alhalinc mcdicntion The minimal amount of ascorbic acid which will present scurvy is about 100 mg daily The amount which should be recommended for the maintenance of good nutrition is a subject of controversy Thic allow ances suggested in this country are given in Table 3 It is belici ed by proponents of other dietary standards that smaller quantities will In ascorbic acid deficiency, connective tissue is defective presumably due to the essentiality of this vitamın for the production of collagen (142) 'The changes in bones tecth and gums which occur in scurvy and the poor healing of wounds, are believed to be secondary to this fundamental defect The hemorrhagic phenomena represent a capillary defect due perhaps to abnormal pericapıllary connective tissue One metabolic function of ascorbic acid has been elucidated recently it acts as a coenzyme in the oxidation of tyrosine (143) This finding explains the abnormal excretion of tyrosine metabolites in scurvy and the return to normal after ascorbic acid has been administered Folic acıd will also correct this metabolic defect (p 125) Relationshups of ascorbic acid to adrenal cortical function have been investigated extensively (144) Stumulation of the adrenal corter leads to depletion of ascorbic acıd stores in the gland but cortical function is maintained even in severe depletion Investigations using ascorbic acid and acetate labeled with Cº indicate that the vitamin exerts an effect on the conversion of acetate to cholesterol and other steroids (145) Ascorbic acid has been reported to prevent the alarm reaction of acute ·136 NUTRITIONAL DIAGNOSIS stress in experimental animals While much remains to be learned about the function of ascorbic acid in the adrenal cortex, available evidence suggests an increased utilization and requirement of ascorbic acid under con ditions of stress It seems advisable therefore to admin ister ascorbic acid in chronic stress states, particularly following burns or other trauma and during prolonged administration of corticotropin The ascorbic acid requirement appears to be increased in hyperthyroidism Plasma ascorbic acid decreases in a number of infections, particularly those of long duration such as tuberculosis or rheumatic fever Whether this decrease represents an increase in ascorbic acid require ment or a redistribution of the vitamin in the body is not clear Although the role of ascorbic acid in infection is not known, it would seem logical to supplement the diet with this vitamin when infections are prolonged Ascorbic acid has a number of biologic functions in addition to those discussed above such as an influence on the hyaluronidase hyaluronic acid reaction an effect on the reaction of small blood vessels to adrenaline and some relationship to secretion of steroid hormones in the ovary (146) Many of the activities of this vitamin suggest that it may function as a respiratory catalyst but to date this has not been demonstrated Ascorbic Acid Deficiency Ascorbic acid deficiency has been induced experimen tally in adults on several occasions (147) Clinical signs of deficiency included hyperkeratotic papules surrounding hair follıcles, exacerbation of acne, perifollicular hemorrhages and petechiae, small hemorrhages in the tips of the interdental papıllae and poor wound healing The gums became purplish, spongy and swollen in sub- ·VITAMIN NUTRITION 137 jects who had previously shown periodontal disease and interruptions of the lamınal dura were noted in x ray films of the teeth In spontaneous scurvy in adults find ings similar to those noted above are observed when deficiency becomes severe, bleeding may occur into any tissue of the body or from any mucous membrane Swelling of joints, edema and anemia are additional findings The gums may be very red, swollen and bleed on slight pressure loosening of the teeth and atrophy of alveolar bone may occur Anemia is common in severe scury in adults and responds to ascorbic acid (115) In infants, the majority of cases of scurvy occur between the ages of 7 and 11 months The most frequent presenting complaints according to Woodruff (143) are irritabılıty, tenderness of the legs and pseudoparalysis, i e failure to move or use the legs Involvement of the arms is less common A history of bleeding or its manzfestation is another frequent presenting symptom Non specific complaints often noted are anorexia diarrhea and fever In typical scurvy the infant lies quietly in the pithed frog” position with legs flexed at the knees and hips fered and externally rotated The slightest jarring or motion causes crying due to the pain which is invoked Costochondral beading the most frequent physi cal finding in Woodruff's series of cases may cause confusion with richets Beading in scurvy is typically “sharp consisting of subluxation of the cartılaginous portion of the anterior chest wall on the bony lateral portion pro ducing an abrupt transition the so called bayonet deformity However, a rounded type of beading similar to richets may be encountered Hemorrhage around erupting teeth is a constant finding with bleeding after manipulation in advanced cases Palpable subperiosteal hemorrhages are frequent particularly in the distal end ·138 NUTRITIONAL DIAGNOSIS of the femur and proximal end of the tibia Bleeding may occur from any of the mucous membranes although hemorrhages into the skin are relatively uncommon, in contrast to scurvy in adults Radiographic examination of the long bones shows characteristic changes at the cartilage - shaft junction appearing earliest at the sites of most active growth, eg, the sternal ends of the ribs, distal end of the femur, Proximal end of the humerus, both ends of the tibia and fibula and distal ends of the radius and ulna Fındıngs include cortical atrophy, the corter being unusually thin in relation to the shaft, and atrophy of the trabecular structure with increased transparency producing a ground glass appearance The provisional zone of calcı fication at the end of the shaft is widened casting a dense shadow, similar changes occur in the periphery of ossi fication centers, best illustrated about the knee (148) This latter change, in conjunction with rarefaction and loss of trabecular markings in the epiphyseal center, as almost specific for scurvy A zone of rarefaction is visible shaftward from the zone of provisional calcification being apparent first near the cortex this plus the extremely thin cortex constitute the corner sign or fracture described by Park This area of rarefaction is weak and fractures may occur here and also in the brittle zone of provisional calcification Comminution of the latter zone into the shaft causes the appearance of spur formation Separation of the epiphysis with lateral displacement may Shadows of subperiosteal hemorrhages are also seen on the roentgenogram the area of hemorrhage be coming clearly outlined by bone formation in the peri osteum after several days of treatment Following therapy, the normal architecture of the bone is fully restored Anemia is quite common in infantile scurvy usually occur ·VITAMIN NUTRITION 139 being hypochromic and due to iron deficiency Occasionally megaloblastic anemız is encountered (p 124) The leukocyte count is often elevated except in subjects with megaloblastic changes in the bone marrow There is an increased output of tyrosine metabolites in the urine when large amounts of this amino acid are ingested The diagnosis of scurvy in infants or adults is dependent on a history of extremely low intake of ascorbic acid for a period of months, at least three in infancy and longer in adults, the presence of symptoms which suggest the disease and characteristic physical findings In infants, radiologic changes are of great assistance The diagnosis of ascorbic acid deficiency in its incipiency is dependent on laboratory tests The concen tration of ascorbic acid in the plasma reflects dietary in take In adults, levels of 06 to 1 mg/100 ml indicate a daily intake of 70 mg or more, levels of less than 02 mg/100 ml an intake of less than 25 mg (17) Unfortunately, low concentrations do not indicate the degree of depletion of bodily stores of ascorbic acid and absence of ascorbic acid in plasma does not indicate scurvy When such levels are encountered, the ascorbic acid content of the white cell platelet layer of blood should be measured Concentrations of ascorbic acid in leukocytes below 2 mg/100 ml should be considered presumptive evidence of scurvy In well nourished adults receiving 70 to 100 mg of ascorbic acid daily, the level of ascorbic acid in white blood cells is 20-30 mg/100 ml Some type of load" test may also be used in evaluating ascorbic acid stores of the body The vitamin may be administered orally or intravenously and the urinary excretion or concentration in the blood measured for several hours thereafter These tests and others involving urinary cycretion of ascorbic acid have been evaluated in a recent ·140 NUTRITIONAL DIAGNOSIS review (17) Woodruff employed the saturation test of Kadji and associates to differentiate scorbutic infants from infants with no ascorbic acid in serum as a result of a poor recent diet In this procedure, 200 mg of ascorbic acid is administered intramuscularly and serum concen tration determined four hours thereafter In practically all infants with scurvy, the four hour level was less than 04 mg/100 ml and in about half of the subjects this level was zero Lowry (17) has proposed a test for measuring tissue deficit under carefully controlled conditions Ascorbic acid is administered in amounts of 500 2000 mg daily, in divided doses to avoid raising the plasma level above 14 mg/100 ml which is the renal threshold and the quantity of the vitamin excreted in the urine is determined Tissue retention should equal tissue deficit when suitable correction is made for destruction of the vitamin Capıllary fragility tests which have been widely used are of almost no value in the diagnosis of ascorbic acid deficiency in view of the many conditions which influence capillary strength VITAMIN D Vitamin D deficiency is rarely observed in adults and is becoming uncommon in infants due to the widespread use of dietary supplements in the early months of life A unique feature of vitamin D metabolism is the forma tion of this vitamin in the skin on exposure to sunlight or ultraviolet rays and consequently only partial depen dence of the body on a dietary supply Actually only small amounts of vitamin D are present in the average diet In several animal species the susceptibility to richets is influenced by dietary chunges such as the inclusion of cereals containing phytic acid which decreases absorption ·VITAMIN NUTRITION 141 of calcium Phytate also appears to interfere with the absorption of calcium in man (149) Since vitamin D is fat soluble, absorption is impaired in conditions asso ciated with decreased absorption of fats as when bile is absent from the intestinal tract or in the steatorrheas Vitamin D consists of 1 group of sterol derivatives in cluding vitamin D activated ergosterol, which is derived from plants and vitamin D3 activated dehydrocholesterol, which is found in animal tissues Vitamin D is measured in International Units, one unit being equivalent to the activity of 0 025 ug of calciferol (crystallıne vitamine D.) In infancy, maximum retention of calcium will be attained with administration of 300-400 IU of vitamin D daily of the diet contains an ample supply of calcium and phos phorus (150) Larger amounts of vitamin D are not beneficial and a daily dose of more than 1800 IU may be deleterious Maximum retention of calcium is associated with good sheletal growth and early dentition The ma jority of children probably require supplementary vitamin D throughout the period of growth and practically all need it during adolescence The recommended allowance for vitamin D is 400 IU daily from birth to 20 years of age (Table 3) Supplements of vitamin D would seem desirable during pregnancy and lactation in view of the increased need of calcium and phosphorus in these conditions In adults the need for supplemental vitamin D appears to be minimal except in unusual circumstances in which occupation or habits present exposure to sunlight Vitamin D functions by increasing absorption of calcium from the intestinal tract, possibly increasing the absorption of phosphorus as well and decreasing the urinary excretion of phosphorus by enhancing reabsorption in the renal tubule The renal influence may be due in ·142 NUTRITIONAL DIAGNOSIS part, to diminished activity of the parathyroid glands which follows a rise in serum calcium induced by vitamin D In addition to maintaining levels of calcium and phos phorus in blood which are suitable for deposition of bone, vitamin D is believed to exert some direct effect at the site of bone formation Recent investigation suggests that vitamin D may activate alkaline phosphatases of bone, kidney and intestine but this enzymatic role of the vita min needs confirmation Normal bone formation requires an adequate supply of calcium and phosphorus as well as vitamin D Vitamin D Deficiency Vitamin D deficiency is characterized by poor retention of calcium and phosphorus and retarded skeletal growth, particularly in infancy and early childhood, and by osteomalacia in adult life The clinical signs of richets vary greatly depending on the seventy of the process and on the age rate of growth and stage of physical des elopment when the disease is active The earliest findings are deformities of the sheleton which have been described so well by Park (151) Craniotabes which may be seen as early as the second month, consists of areas of softening of the skull usually involving the occipital and parietal bones along the lambdoidal suture The anterior fontanel does not close at the usual tine and the margins are soft, as are the margins of the cranial bones that form the sutures In severe nckets the skull can become very thick particularly at the frontal and parietal eminences resulting in the so-called rachitic "bossing of the skull Thickening may occur concomitantly with thinning and craniotabes in the back of the skul Another early sign of nichets is enlargement of the cos. tochondral junctions often referred to as beading of the ·VITASIN NUTRITIOV 143 Occurs nbs or the rachutic rosary Other deformities of the thorax include pigeon breast and Harrisons grooves The latter are depressions at the sides of the chest at the level of the diphragmatic attachments which develop as a result of muscle pull Abdominal distention commonly accompanies rickets and accentuates these grooves The rachitic child shows postural kyphosis on sitting and lordosis on standing The long bones become enlarged at the ends, most readily seen at the wrists and ankles The shafts of the bones may be curved the direction of curvature being dependent on the age at which rickets Anterior bowing of the tubia or "saber shin” occurs before weight bearing while lateral deformity, bow legs and knock knees, develop following standing and walking The waddling gait in severe nchets is due to a twist in the tibia and femur (151) Narrowing of the pelvic outlet may occur but injury is rarely permanent ercept in rickets of long duration Primary dentition is delayed in nchets and the permanent teeth may show serious defects in enamel formation The muscles are hypotonic and motor development is delayed, the child is slow in sitting and walking This muscular relaxation is also responsible for the pot belly Tetany due to low serun calcium concentration may complicate the clinical picture of nickets Roentgenographic examination of the bones will reveal abnormalities ercept in early nckets and healing may be followed by serial roentgenograms Characteristic changes are observed at the cartilage-shaft junctions and in the shafts of the long bones (151) The end of the shaft appears cupped in the x ray first visible at both ends of the fibula and the lower end of the ulna, later in the ends of the tibia and the lower ends of the radius and ·144 NUTRITIONAL DIAGNOSIS femur Cupping occurs also in scurvy and in chon drodystrophy Spreading of the end of the shaft is another common finding in rickets as is fringing which appears as thread like shadows extending from the end of the shaft into the transparent cartilage The end of the shaft may have an irregular dotted or stippled appearance The trabecular network of the shaft becomes coarse and there is a marked decrease in bone density in severe rickets In advanced stages of the disease, the cortex may be thın or non visible or it may be thickened and appear reduplicated Curva tures of the bones are another characteristic finding In vitamin D deficiency fecal excretion of calcium and phosphorus is increased while urinary excretion of cal cium is decreased and that of phosphorus increased The concentration of inorganic phosphorus in the serum de creases to less than 4 mg/100 ml (25 mEq/1) while the concentration of calcium may remain normal or decrease Determination of alkaline phosphatase in serum is the most important single procedure for diagnosing rickets in its early stages Normal concentration in young children ranges from 5 to 15 Bodansky units Elevation of alkaline phosphatase above 20 units is highly suggestive of rickets since few other conditions influence phos phatase activity in this age group Such elevation occurs before clinical richets is evident Serial determinations of serum phosphatase are useful in following therapy since the return to normal is delayed until healing is complete Rickets which is refractory to treatment is observed occasionally, especially in children over the age of three The metabolic defect in this condition is not understood, there seems to be interference with the normal calcifying action of vitamin D Massive doses of the vitamin may ·VITAMIN NUTRITIOV 145 promote healing but some of the metabolic abnormalities may not be corrected (152) Relationslups between rickets and the Finconi syndromc laic been discussed previously (p 42) Osteomalacia is an uncommon discisc wluch presumably is the adult counterpart of richets It occurs most frequently during pregnancy and lactation and is characterized by osteoporosis, deformity and fracture of bones and tetany The first symptom is usually pain in the back and sacral area Muscular weakness is an associated finding which may be pronounced in the adductor muscles of the thighs Stiffness and contractures of the extremities have been reported When deformity develops, it is seen first in the areas in which pain occurs, that is, in the spine and pelvis X ray examination will show extensive dcmineralization with dislocation and fractures The concentration of serum calcium decreases, often to levels below 7mg/100 ml, (35mEq/l) and the level of alkaline serum phosphatase rises above the normal adult value of 3 to 5 Bodansky units Since a number of diseases influence phosphatase concentration in the blood in adults a high level should not be considered evidence of osteomalacia in the absence of other findings Osteoporosis and tetany may occur in association with sprue the celiac syndrome and idiopathic steatorrhea In these conditions both calcium and vitamin D are poorly absorbed from the intestinal tract Massive doses of vitamin D given over long periods of time may lead to toxic reactions These include elevation of serum calcium metastatic calcification loss of weight, vomiting and diarrhea Death may occur from renal failure Intoxication may be detected at an early stage by serum calcium determination a nse above 11 5 mg/100 ml (6 m Eq/1) being indicative of excessive dosage ·146 NUTRITIONAL DIAGNOSIS VITAMIN E Vitamin E has not been shown unequivocally to be essential in human nutrition although evidence suggests that this is the case In experimental animals, manifesta tions of vitamin E deficiency include fetal resorption and dystrophic changes in skeletal muscle In certain clinical diseases in man which resemble experimental deficiency, namely, habitual abortion and progressive muscular dys trophy, therapy with vitamin E has been attempted Beneficial effects have not been demonstrated in these conditions or in a number of other pathologic states in wluch vitamin E has been prescribed (153) An attempt to produce experimental vitamin E defi ciency in adult men is under way at present (154) The only abnormal findings after more than three years on a diet very low in vitamin E are a decrease in the concen tration of tocopherols in blood and excessive hemolysis of erythrocytes when tested with hydrogen peroxide in vitro It seems unlikely that primary deficiency of vitamin E will occur in healthy adults However, deficiency might arise as a result of impaired absorption, increased requirement or some abnormality in the metabolism of the vitamin PI ma tocopherol levels have been found to be much lower in infants than in adults Normal levels in the former range from 0 23 to 0 43 mg per 100 ml, in the latter from 10 to 12 mg per 100 ml (155) Gyorgy and associates (156) observed that erythrocytes of newborn infants were more sensitive to hemolysis by hydrogen per oxide than those of adults and that this sensitivity could be corrected by tocopherol administration Similar sensi tivity to hemolysis has been found in premature infants (157) It seems likely that supplementation of the diet of premature infants with tocopherol may be desirable ·VITAMIN NUTRITIOV 147 since fat absorption is defective and both whole cow's milk and stored human milk hue limited tocopherol content Evaluation of vitamin E nutntion must rcst, at present, upon determination of plasma tocopherol concentration and the use of the in vitro erythrocyte hemolysis test Absorption of vitamin E may be determined by a tolerance test similar to that described for vitamin A Subjects are given a large dosc of tocopherol (5-20 mg per kg body weight) and blood samples taken at 0, 3, 6, 9, 12 and 24 hours Low curves have been reported in spruc, fibrocystic disease of the pancreas, the celiac syndromo and in some but not all cases of liver disease (155) Analysis of tissues specimens, obtained at biopsy, for tocopherol content may prove to be informative VITAMIN K Vitamin K is important in human nutrition but deficiency is rarely observed in the absence of some complıcating disease except in the infant during the first ten days after birth Vitamin K is present in a large variety of foods and is synthetized by bacteria in the intestinal tract, hence dietary deficiency is an unlikely possibility Deficiency in the first few days of life may be due to inadequate intake during this period or to sterility of the intestinal tract The daily requirement of the infant is approximately 10 ug (4a) In the adult, the requrement is unknown but is apparently small and easily sup plied by the ordinary diet in addition to the amount available from intestinal synthesis Since naturally occurring forms of vitamin K are fat soluble, deficiency is observed in a number of diseases in which fat absorption is impaired such as obstructive jaundice biliary fistula, and the steatortheas sprue the ·148 NUTRITIONAL DIAGNOSIS celiac syndrome, idiopathic steatorrhea and pancreatic fibrosis Poor absorption of vitamin K may lead to defi ciency in chronic ulcerative colitis, regional leitis, other severe diarrheal states and following operative removal or short circuiting of large sections of the intestınal tract Intestinal synthesis of vitamin K may be depressed by prolonged administration of antibiotics Vitamin K is essential for the formation of prothrombin which is necessary for blood coagulation The precise role of vitamin K in prothrombin formation by the liver is unknown it has been postulated that it may function as the prosthetic group of an enzyme (158) Functions for vitamin K other than involvement in the synthesis of prothrombin have been suggested (4a, 146) In animal experiments, vascular and parenchymal lesions which could lead to hemorrhage or tissue injury have been found in the brain in vitamin K deficiency Whether tissue lesions precede hemorrhage in infants deficient in vitamin K is unknown It is of interest, however, that not a single instance of cerebral hemorrhage was noted in 1531 chil dren in Oslo who were bom of women who received vitamin K during the last weeks of pregnancy (159) Vitamin K Deficiency The outstanding manifestation of vitamin K deficiency is hemorrhage which may occur into any tissue or from any mucous membrane Cerebral hemorrhage is frequent in infants deficient in vitamin K and has also occurred in adults Diagnosis of vitamin K deficiency is dependent on estimation of prothrombin activity of blood A number of procedures are available for this purpose all of which consist of indirect estimation of prothrombin concentration (160) Prothrombin time may be prolonged in conditions not ·VITAVIIN NUTRITIOV 149 associated with vitamin K deficiency A number of anticoagulants which are used in the control of thrombosis and large doses of salicylates decrease prothrombin ac tivity In severe laver disease, the formation of prothrombin is defective but administration of vitamin K is not beneficial ·NUTRITIONAL DIAGNOSIS, THE FUTURE FROM "ROM the foregoing discussion, it is obvious that much has been learned about the intricacies of nu tritional problems and that numerous methods have been developed that are useful in delineating metabolic ab normalities and nutritional status It is of interest to spec ulate concerning the future of the science of nutrition as it may be applicable to diagnostic and therapeutic medı cine Certainly much more information will be forth coming about interrelationships and balance among nu trients Knowledge of nutritional aberrations in diseases not due primarily to nutritional fault is indeed meagre and should receive increasing attention The rapid strides made in biophysics and biochemistry in recent years will undoubtedly provide techniques which will be valuable in elucidating metabolic abnormalities Many of the dis turbances which are uncovered may be amenable to nu tritional therapy One promising approach in nutritional diagnosis appears to be measurement of enzyme concentrations in tissue specimens obtained by biopsy Another is the possibility of testing nutritional adequacy by stressing various en zyme systems which may be found to be sensitive to the supply of a given nutrient and measuring metabolic end products Isotopic techniques should assist in discovering specific roles of nutrients in normal bodily function and in clarifying dysfunction that occurs in disease They may prove increasingly useful in diagnosis as well While scientific advances may make many of the pro 150 ·NUTRITIOVAL DIAGNOSIS THE FUTURE 151 cedures described in this monograph obsolete in the not too distant future, the approach to nutritional diagnosis will continuc to be astute clinical cu aluation of all facets of the patient and his problems Data obtained from the dietary, environmental and medical histones, from plays cal examination and laboratory procedures must be combined into an integrated wholc for accurate diagnosis The physician must be 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