Published Science

Basal plasma levels of thyroxine (T4), triiodothyronine (T3) and reverse T3 were determined by radioimmunoassay in 44 control subjects, 44 Type 1 (insulin-dependent) and 39 Type 2 (non insulin-dependent) diabetic patients aged from 15 to 75 years. All were clinically euthyroid. The quality of diabetic control was assessed by the percentage of glycosylated haemoglobin. In both the diabetic groups there was a significant decrease in T3 and a rise in reverse T3 whereas T4 was normal. We found no significant differences between plasma thyroid hormone levels in Type 1 and Type 2 diabetic patients. In the poorly controlled diabetics (glycosylated haemoglobin greater than or equal to 12%), T3 was 90 +/- 5 ng/dl, which differed significantly from the level found in the better controlled patients (106 +/- 5 ng/dl, p less than 0.01). In the diabetic patients without associated illness, a negative linear correlation was found between T3 and glycosylated haemoglobin and a positive correlation between reverse T3/T3 and glycosylated haemoglobin. No correlation between T3 or reverse T3 and fasting blood glucose could be established. In conclusion, many diabetics showed a low T3 syndrome suggesting that there may be an impairment in the extrathyroidal conversion of T4 to T3. This may well be enhanced by a poor diabetic control (glycosylated haemoglobin greater than or equal to 12%).

1. The association between vegetarianism and blood pressure was studied in relation to obesity, sex and aspects of lifestyle in 180 Seventh-day Adventists and 113 Mormons aged 25-44 y. 2. Volunteers completed a questionnaire, a 1-day diet record and submitted to standardized measurements of blood pressure, heart rate and body size. 3. Ninety-eight Adventist "vegetarians' were comparable to the 113 Mormon omnivores for strength of religious affiliation, consumption of alcohol, tea and coffee and use of tobacco, but were significantly less obese. 4. Obesity correlated positively with blood pressures in males and females of both diet classes. Age showed a positive correlation with blood pressure in females only. 5. Adjustment of blood pressures for age and Quetelet Index indicated that there is an additional blood pressure reducing effect associated with a vegetarian diet.

The concentrations of total and high density lipoprotein (HDL)-cholesterol and the ratio of HDL-cholesterol to total cholesterol have been examined in groups of non-vegetarian, semi-lactovegetarian, lactovegetarian and marcobiotic men aged 30-39 years and boys aged 6-11 years. In the men, the concentration of total cholesterol ranged from 3.8 mmol/l in the macrobiotics to 5.5 mmol/l in the non-vegetarians, while the concentration of HDL-cholesterol varied between 1.2 mmol/l and 1.4 mmol/l. The ratio of HDL-cholesterol/total cholesterol varied from 0.23 in the non-vegetarian men to 0.31 in the macrobiotics and it was negatively related to the body mass index (ratio of weight to height2). In the boys the concentration of total cholesterol ranged from 3.4 mmol/l in the macrobiotics to 4.3 mmol/l in the semi-lactovegetarians, while the concentration of HDL-cholesterol varied between 1.2 mmol/l to 1.4 mmol/l. The ratio of HDL-cholesterol/total cholesterol was similar in the four groups (0.33-0.35). The concentration of cholesterol in various lipoprotein fractions separated by ultracentrifugation was also estimated in subsamples of the populations. The variation between groups in the concentration of HDL-cholesterol appeared to be largely due to variations in the concentration of cholesterol in the HDL2 fraction (1.063 less than rho 20 less than 1.125).

1. Several investigators have found that the development of post-exercise ketosis is not counteracted by glucose ingestion. Post-exercise ketosis might therefore have more in common with diabetic ketoacidosis than with starvation ketosis. 2. The effects of ingesting 100 g of glucose, alanine or starch were therefore studied in subjects rendered hyperketonaemic by prolonged running on a low carbohydrate diet, or by 65 h of starvation. These substances were also ingested by normal post-prandial subjects. 3. The runners developed post-exercise ketosis (1.81 +/- S.D. 0.81 mmol/l), which was counteracted by alanine and glucose, but only minimally by starch. 4. Fasting caused a variable ketosis (2.19 +/- S.D. 1.63 mmol/l), also counteracted by glucose and less by starch, but alanine caused vomiting. 5. Glucose and alanine lowered the blood ketone body levels of the post-prandial subjects. 6. The rising ketone body levels in starvation and after exercise were accompanied by simultaneous increases in the plasma insulin/glucagon ratios; in both, glucose ingestion increased the ratio further, while alanine decreased it. 7. It is concluded that there is no essential difference between established post-exercise and starvation ketosis, and that the blood fuel-hormone changes do not correlate with the changes in blood ketone body concentrations.

The effects of vegetarian fasting were evaluated in 14 grossly obese patients who participated in a program comprising 5 weeks' fasting in a lactovegetarian health center. Before and after the fasting period the patients were hospitalized and put on a standardized weight-maintaining diet; at the health center they consumed vegetable juices containing less than 1 MJ and 3 g of protein per day. The weight reduction (mean +/- S.D.) was 13.4 +/- 5.0 kg (from 132.0 +/- 27.2 to 118.6 +/- 16.1 kg). Except for the first few days the patients had no severe hunger sensations. No severe adverse clinical effects were noted. The laboratory status--comprising serum or plasma levels of minerals, protein, and lipids; hematological data; and variables reflecting liver and thyroid function--revealed abnormal group mean values only for ferritin and the acute-phase reactants haptoglobin, C-reactive protein, and anti-chymotrypsin in the obese. The levels of potassium, retinol-binding protein, and haptoglobin decreased, and aminotransferase and lactate dehydrogenase activities and free fatty acid and glycerol concentrations increased as a result of the fasting. The most striking effect of the weight reduction was an increase in the HDL cholesterol levels. Fasting according to the described regimen thus seems to provide a safe method for treatment of obese patients.

Thirty-nine preschool children consuming different types of vegetarian diets were studied. Type and amount of carbohydrate, fat, protein, and amount of sodium and cholesterol provided by their diets were more like intakes suggested in the proposed Dietary Goals for the United States than to levels in usual diets of nonvegetarian children. Macrobiotic vegetarian children consumed less animal food than did other vegetarian children. The mean intake of vitamin D of macrobiotics was an eighth of the Recommended Dietary Allowance and mean serum alkaline phosphatase values were elevated. The mean intake of vitamin B12 levels were normal. Vegan macrobiotic children had the lowest intakes of vitamins B12 and D. Other vegetarians' mean intakes of these vitamins met the Recommended Dietary Allowance. Mean iron intakes of the vegetarians approximated the Recommended Dietary Allowance. Hematological indices were suggestive of mild iron deficiency anemia in a quarter of subjects. Serum cholesterol values were low for the group. Physical measurements were within normal limits and macrobiotic vegetarians were not smaller or leaner than other vegetarian children. The nutritional difficulties discovered could be corrected by careful planning of vegetarian children's diets while preserving the beneficial qualities of the diet in other respects.

Retinal studies were done in 181 postpubescent, insulin-dependent diabetic patients who developed diabetes before the age of 20. Retinal studies included serial direct ophthalmoscopic examinations, stereoscopic fundus photography and fluorescein angiography. At the time of retinal studies, muscle biopsies also were done to measure capillary basement membrane thickness (CBMT) as an index of early microvascular changes in skeletal muscles. Assessment of clinical metabolic control, interpretation of retinal findings, and CBMT were done independently. No retinopathy was detected in patients observed continuously and known to have been in higher degrees of metabolic control. Twenty-five patients in lower degrees of control for extended periods had retinopathy. CBMT was found to be labile and to progress or regress within a year depending on the degree of control. All patients in lower degrees of control with retinopathy had increased CBMT, but if they subsequently attained and maintained a high degree of control for a year, then CBMT diminished and there was no progression of retinopathy. Our study demonstrates that a high degree of metabolic control delays, and may prevent, microvascular changes, and confirms other studies indicating that most postpubescent, insulin-dependent diabetic patients will develop retinopathy within 15 years unless a relatively high degree of control is maintained.

The present studies were undertaken to assess the mechanisms responsible for cortisol-induced insulin resistance in man. The insulin dose-response characteristics for suppression of glucose production and stimulation of glucose utilization and their relationship to monocyte and erythrocyte insulin receptor binding were determined in six normal volunteers after 24-h infusion of cortisol and 24-h infusion of saline. The infusion of cortisol (2 /xg kg" 1 min" 1) increased the plasma cortisol concentration approximately 4-fold (37 ± 3 vs. 14 ± 1 jitg/dl; P \textless 0.01) to values observed during moderately severe stress in man. This hypercortisolemia increased postabsorptive plasma glucose (126 ± 2 vs. 97 ± 2 mg/dl; P \textless 0.01) and plasma insulin (16 ± 2 vs. 10 ± 2 juU/ml; P \textless 0.01) concentrations and rates of glucose production (2.4 ± 0.1 vs. 2.1 ±-0.1 mg kg" 1 min" 1 ; P \textless 0.01) and utilization (2.5 ± 0.1 vs. 2.1 ± 0.1 mg kg" 1 min"'; P \textless 0.01). Insulin dose-response curves for both suppression of glucose production (half-maximal response at 81 ± 19 vs. 31 ± P \textless 0.05) and stimulation of glucose utilization (half-maximal response at 104 ± 9 us. 64 ± 7 juU/ml; P \textless 0.01) were shifted to the right, with preservation of normal maximal responses to insulin. Neither monocyte nor erythrocyte insulin binding was decreased. However, except at near-maximal insulin receptor occupancy, the action of insulin on glucose production and utilization per number of monocyte and erythrocyte insulin receptors occupied was decreased. These results indicate that the cortisol-induced insulin resistance in man is due to a decrease in both hepatic and extrahepatic sensitivity to insulin. Assuming that insulin binding to monocytes and erythrocytes reflects insulin binding in insulin-sensitive tissues, this decrease in insulin action can be explained on the basis of a postreceptor defect. (J Clin Endocrinol Metab 54: 131, 1982)

We studied plasma concentrations of thyrotropin (TSH), prolactin and growth hormone (GH) after injection of 500 microgram of thyrotropin-releasing hormone (TRH) in 10 patients with acute anorexia nervosa, subsequent to initial nutritional stabilization and again after weight recovery. Plasma thyroxine levels were normal throughout, whereas plasma triiodothyronine levels were low initially but rose with weight gain. The TSH secretory response to TRH was delayed and prolonged during the initial study but showed a normal overall quantitative response, except for two patients who showed no TSH rise. Following weight gain the TSH response was more rapid, and positive correlations were found between body weight and peak TSH levels and rapidity of TSH response. Six of 10 patients, however, continued to exhibit a delayed TSH peak response, the average response was markedly increased in comparison with that in normal females. The prolactin response curves were normal at both times. Rises in GH following TRH were observed in two patients prior to and in one patient after weight gain. We conclude that acute anorexia nervosa, with its concomitant profound weight loss, is accompanied by abnormalities in the hypothalamo-pituitary-thyroid axis, which are reversed only in part with improvement in the illness and weight gain, suggesting the persistence of disordered neuroendocrine function in this illness.

Unusually large coastal dune formations occur on the east coast of Cape York Peninsula, North Queensland, an area which experiences a seasonally humid tropical climate. This paper describes the morphology and development of dunes at Cape Bedford and Cape Flattery, north of Cooktown. The dunefield consists of several generations of superimposed parabolic and elongate parabolic dunes, the older members of which are deeply weathered. The large scale of dune development in this area reflects an abundant sand supply from widespread outcrops of Mesozoic sandstones and older granites on the neighbouring part of Cape York Peninsula, and the exposed location of Cape Bedford and Cape Flattery in relation to the prevailing southeasterly winds. Many of the dunes are stabilized at the present day, and the major periods of dune formation appear to have taken place earlier in the Holocene or Pleistocene.

[History of early nutrition science, 1885-1900, centered around Wilbur O. Atwater]

Post-exercise ketosis was first described in 1909 by Forssner, who found that his daily excretion of acetone in the urine was increased on days when he had undertaken a brisk walk in the morning. Athletes on unrestricted diets eat more, particularly carbohydrates, than non-athletes, and have lower post-exercise ketone body levels. They also have lower plasma glucagon, growth hormone, catecholamine, and free-fatty acid levels during sub-maximal exercise. On a standard 12 MJ/d diet, however, non-athletes have the lower post-exercise ketone body levels. The hormone response of athletes and non-athletes to exercise can similarly be reversed by dietary manipulation. The carbohydrate status of the body is, therefore, probably the main determinant of the type of blood hormone profile that develops during exercise, and the degree of ketosis that develops after exercise.

The findings showed that graduated homemakers had final diet scores after participation which were significantly higher than their initial scores upon enrollment. While regression occurred after leaving the program, the follow-up scores remained significantly higher than initial scores. In comparing initial diets of newly enrolled homemakers to the follow-up diets of graduated homemakers, their scores were significantly higher. However, there was no significant difference between the initial diets of graduated and dropout homemakers. [Based upon the study of 129 graduated homemakers and 47 drop-outs.]

Ketone bodies accumulate in the plasma in conditions of fasting and uncontrolled diabetes. The initiating event is a change in the molar ratio of glucagon:insulin. Insulin deficiency triggers the lipolytic process in adipose tissue with the result that free fatty acids pass into the plasma for uptake by liver and other tissues. Glucagon appears to be the primary hormone involved in the induction of fatty acid oxidation and ketogenesis in the liver. It acts by acutely dropping hepatic malonyl-CoA concentrations as a consequence of inhibitory effects exerted in the glycolytic pathway and on acetyl-CoA carboxylase (EC 6.4.1.2). The fall in malonyl-CoA concentration activates carnitine acyltransferase I (EC 2.3.1.21) such that long-chain fatty acids can be transported through the inner mitochondrial membrane to the enzymes of fatty acid oxidation and ketogenesis. The latter are high-capacity systems assuring that fatty acids entering the mitochondria are rapidly oxidized to ketone bodies. Thus, the rate-controlling step for ketogenesis is carnitine acyltransferase I. Administration of food after a fast, or of insulin to the diabetic subject, reduces plasma free fatty acid concentrations, increases the liver concentration of malonyl-CoA, inhibits carnitine acyltransferase I and reverses the ketogenic process.

The intake of trans fatty acids by subjects adhering to the normal Swedish diet or to different vegetarian regimes was studied, using chemical analysis of duplicate portions. Trans-octadecenoic acid was 5.0, 3.9, and 1.8% of dietary fatty acid in the normal, lactovegetarian, and vegan diets, respectively, corresponding to 2.0, 1.3, and 0.5% of energy intake. The results are related to the content of trans-octadecenoic acid in some edible fats.

Acute respiratory failure developed in three patients needing ventilatory support within hours after total parenteral nutrition was started. We postulate that the high carbohydrate load provided in the parenteral solution resulted in the use of glucose as the primary energy source, with the development of substantial increases in the carbon dioxide production and the respiratory quotient. Because these patients had a relatively fixed ventilatory response, hypercapnia ensued. Excessive carbohydrate loading may precipitate respiratory acidosis in patients unable to adequately improve their alveolar ventilation when compensating for increased carbon dioxide production.

The nutritional status of 23 vegan children between one and five years was assessed using anthropometric and dietary criteria. All of the children had been breastfed for at least the first six months of life and in most cases well into the second year. The majority of the children were growing normally but they did tend to be smaller in stature and lighter in weight when compared with standards. Energy, calcium and vitamin D intakes were usually below those recommended. Their diets, however, were generally adequate but a few children had low intakes of riboflavin and vitamin B12. It is concluded that, provided sufficient care is taken, a vegan diet can meet the nutritional requirements of the preschool child.

In comparison with matched nonvegetarian women, postmenopausal vegetarian women were found to have lower urinary levels of estriol and total estrogens, lower plasma prolactin levels, and higher plasma sex hormone-binding globulin (SHBG) levels. These differences were not explained by differences in body weight or obesity. Plasma SHBG levels were highly correlated with plasma high-density lipoprotein cholesterol levels, which were also higher in vegetarians than in nonvegetarians. These hormonal differences may explain the lower rates of endometrial and possibly breast cancer that have been observed previously in vegetarian women.

The effect of a virtually cholesterol-free, high-linoleic-acid vegetarian diet and a high-linoleic-acid "normal" diet with a moderate cholesterol content was tested in 39 children heterozygote for hypercholesterolemia type II-A. The diets were administered in an outpatient cross-over design of two periods of 10 weeks each and the serum lipoproteins were analyzed at the end of the two 10-week periods. The vegetarian diet induced a decrease in serum concentrations of LDL-II total and free cholesterol and of apo-B, by an average of 10%, whereas HDL cholesterol and apo-A-I decreased by 4%. The disproportionately large change in LDL compared to the small change in HDL was interpreted as an antiatherogenic effect of the vegetarian diet.

This paper reviews recent research on the characterization, properties, and definition of dietary fiber as well as its possible role in colonic carcinogenesis and diverticulosis. Despite progress in analytic methods and characterization, an accepted definition and terminology for fiber are lacking as is an accurate, rapid method for measurement of total dietary fiber or fiber in foods. Mechanisms of effects of fiber in the gut and the significant of interactions between fiber, nutrients gut flora and associated metabolites, and enteric secretions are unclear. Epidemiologic and experimental data indicate an increased risk of diverticular disease and colonic cancer with low-fiber intakes; however, genetic, environmental, cultural, dietary, and other variables were often uncontrolled in the epidemiologic studies. Thus, conclusive evidence for a causal relationship between low intake of fiber and diverticulosis or colonic cancer is not available, and the question whether first protects against human colonic cancer and/or diverticulosis is not completely resolved. Clinical trials in which symptomatic diverticular disease was treated with supplementary dietary fiber have generally had favorable results. Numerous specific questions require additional study before a role for dietary fiber in the prevention of human colonic diverticulosis and cancer of the colon can be established. Suggestions for possible future investigation are provided.

Iron and zinc status of 56 Seventh-Day Adventist Canadian women (mean age 52.9 +/- 15.3 yr) following vegetarian diets for 19 +/- 17 yr were investigated. Energy, protein, iron, available iron, zinc, and total dietary fiber intakes were calculated from 3-day dietary records. Hemoglobin, serum iron, total iron binding capacity, serum and hair zinc concentrations were also determined. Plant products provided 92 and 77% of the total dietary iron and zinc intakes, respectively. Calculated mean daily intakes (+/- SD) for energy, protein, iron, zinc, and total dietary fiber were 1630 +/- 354 kcal, 58 +/- 14 g, 12.5 +/- 3.0 mg, 9.2 +/- 2.5 mg, and 30.9 +/- 11.0 g, respectively. Mean hemoglobin (13.1 +/- 1.0 g/dl), calculated serum transferrin saturation (37.5 +/- 12.9%), mean serum zinc (99 +/- 24 microgram/dl), and hair zinc concentrations (187 +/- 44 ppm) were all within the normal range. The iron and zinc status of these long-term Seventh-Day Adventist vegetarian women appeared adequate despite their low intake of readily absorbed iron and zinc from flesh foods and their high intake of total dietary fiber and phytate.

A case is presented of megaloblastic anemia with metabolic acidosis. The baby was eleven months old. She was strictly fed with human milk from a vegetarian mother. Baby's and mother's B 12 serum levels were low. Baby's weight and neurological development were retarded. Complications included acido-c …

Serum levels of T4, T3, rT3, RT3U and TSH were estimated in 12 obese women in the course of a 14-day fasting. Seven of these patients were treated with T3 in a daily dose of 60--80 micrograms. Fasting led to a small increase of serum T4, while fasting combined with T3 administration was accompanied by a small decrease of serum T4. Serum T3 decreased in the course of the first 2 days of fasting to 40--50% of initial values and remained at this low level up to the 15th day of fasting. In the T3 treated group a prompt increase of serum T3 was recorded (+80%), followed by a steady decrease, reaching the control values on day 15, in spite of a continuous T3 administration. Serum rT3 in the untreated fasting group steadily increased up to the 12th day (+43%) and then dropped below the control value (-28%). In the treated group after a non-significant increase (+22%), a decrease of serum rT3 was also observed (-42%). Fasting was accompanied by a tendency to increased serum RT3U values, in the T3 treated group no change occurred. TSH in the untreated fasting women remained practically unchanged while T3 administration was accompanied by a tendency to a transient decrease. The heart rate showed a non-significant tendency to increase in the T3 treated group and the last week of fasting was also accompanied in several patients by a larger weight loss. These results suggest that in addition to an enhanced synthesis of rT3 to the detriment of a decreased production of T3 from T4, an increased catabolism of administered T3 and of endogenous rT3 is involved in a strict calorie restriction. An abortive T3-TRH-TSH feed-back may also operate in these conditions.

Thyroid hormone abnormalities in serum were investigated in 47 patients with diabetes mellitus. Although no significant differences in T4 were found between normal subjects and diabetics, a group of diabetics whose fasting blood sugar levels were over 250 mg/dl showed significantly higher reverse T3 (rT3) (p less than 0.01) and lower T3 levels (p less than 0.05) than healthy controls. A significant correlation was observed between rT3 and FFA levels in diabetics. Moreover, patients in diabetic ketoacidosis showed markedly high rT3 with low T3 levels. With insulin treatment, these levels returned to normal in several days. These findings suggest that the reduction of T3 and the increase of rT3 may indicate an adaptation to limit catabolism in diabetics.

Throughout its history, medicine has benefited from scientific discov­ eries made in complementary fields such as chemistry, physics and biology. Thus, in the middle of the last century, the works of Pasteur, a chemist and biologist, by revealing the world of micro-organisms, bacteria and viruses, made it possible to control a considerable number of often fatal diseases. Guided by the work of this inspired biologist, the English surgeon, Sir Joseph Lister, developed aseptic techniques which have rendered possible the spectacular achievements of modern surgery. It is largely due to such advances that the life-expectancy of man, 50 years at the turn of the century (1900), approaches 75 years in 1981. Even today, however, in spite of this, two groups of ailments, arter­ iosclerosis and cancer, are responsible for 70 per cent of human deaths both in Canada and in the United States of America. The former is a degenerative process of the arterial system, the latter an uncontrolled and destructive cellular proliferation. Although several predisposing factors are known, the essential cause of these conditions is wholly unknown. As long as this ignorance of the etiology persists, all forms of therapy can be no more than palliative.

Isocaloric 5.61 mJ (1,340 kcal) formula diets involving the isocaloric exchange of fat and carbohydrate were fed to 21 obese persons selected for sex, height, and weight before the start of the treatment and distributed over three groups. The weight loss observed during the carbohydrate-restricted diets was significantly greater than during the high-carbohydrate diet. After 28 days of treatment the weight loss recorded on the high-carbohydrate diet was 9.5 +/- 0.7 kg, as compared to 11.4 +/- 0.7 kg (p less than 0.05) on the corn oil-containing diet and 12.5 +/- 0.9 kg (p less than 0.01) on the butter-fat-containing diet. The weight loss achieved was not dependent on the type of fat administered (saturated vs. polyunsaturated). When calculated cumulatively, sodium excretion during the first 7 days was significantly greater on the low-carbohydrate diet, whereas after 28 days the total amount of sodium excreted was highest on the high-carbohydrate diet. Potassium excretion during the low-carbohydrate diets was significantly greater for as long as 14 days, but at the end of the experimental period the observed differences no longer attained statistical significance. At no time did the intake and loss of fluid and the balances calculated therefrom show significant differences. From the findings obtained it appears that the alterations in the water and electrolyte balance observed during the low-carbohydrate diets are reversible phenomena and should thus not be regarded as causal agents of the different weight reduction.

Caprylic and capric acid esters and their applications in medical, nutritional and dietetic uses are described. Medium chain triglycer-ides (MCT) as a tool in the control of obesity, control in the choles-terol deposition in the tissues as well as a means of lowering serum cholesterol are cited as unique characteristics of such lipids. MCT as a source of quick energy and high energy is suggested as an alterna-tive to the conventional fats and oils (LCT). Dietetic and nutritional application utilizing the unique characteristics of caprylic and capric acid esters is indicated as alternatives to conventional fats and oils. The mono-diglycerides of caprylic and capric acid as cholesterol dis-solving agents in treating of patients having cholesterol gallstones is described to illustrate the unique solvency properties of such mono esters in medical applications. The possibility of such mono esters of di- and polyhydric alcohols to act as co-solvents for oil and water systems is suggested which can be applied in medical, pharmaceuti-cal and allied fields. Structured lipids with a predominance of capry-lic and capric acid to modify the properties of triglycerides is described for hyperalimentation uses as well as the special nutri-tional and dietetic needs.

Summary. Data are discussed which demonstrate that insulin plays an important role in sodium metabolism. The primary action of insulin on sodium balance is exerted on the kidney. Increases in plasma insulin concentration within the physiological range stimulate sodium reabsorption by the distal nephron segments and this effect is independent of changes in circulating metabolites or other hormones. Several clinical situations are reviewed: sodium wasting in poorly controlled diabetics, natriuresis of starvation, anti-natriuresis of refeeding and hypertension of obesity, in which insulin-mediated changes in sodium balance have been shown to play an important pathophysiological role.

Three categories of dietary adaptation are recognized--faunivory, frugivory, and folivory--according to the distinctive structural and biochemical features of animal matter, fruit, and leaves respectively, and the predominance of only one in the diets of most species. Mammals subsisting mainly on animal matter have a simple stomach and colon and a long small intestine, whereas folivorous species have a complex stomach and/or an enlarged caecum and colon; mammals eating mostly fruit have an intermediate morphology, according to the nature of the fruit and their tendency to supplement this diet with either animal matter or leaves. The frugivorous group are mostly primates: 50 of the 78 mammalian species, and 117 of the 180 individuals included in this analysis are primates. Coefficients of gut differentiation, the ratio of stomach and large intestine to small intestine (by area, weight, and volume), are low in faunivores and high in folivores; the continuous spread of coefficients reflects the different degrees of adaptation to these two dietary extremes. Interspecific comparisons are developed by allowing for allometric factors. In faunivores, in which fermentation is minimal, the volume of stomach and large intestine is related to actual body size, whereas these chambers are more voluminous in larger frugivores and mid-gut fermenting folivores; fore-gut fermenters show a marked decrease in capacity with increasing body size. Surface areas for absorption are related to metabolic body size, directly so in frugivores; area for absorption is relatively less in larger faunivores and more in large folivores, especially those with large stomachs. Indices of gut specialization are derived from these regressions by nonlinear transformation, with references to the main functional features of capacity for fermentation and surface area for absorption. These are directly comparable with the dietary index, derived from quantitative feeding data displayed on a three-dimensional graph, with all species within a crescentic path from 100% faunivory through 55--80% frugivory to 100% folivory, perhaps illustrating, at least for primates, the evolutionary path from primitive insectivorous forms through three major ecological grades.

The zinc and copper content of seventy-four foods was determined by atomic absorption spectrophotometry. Each of these foods was reported to have been consumed by practicing vegetarians. Legumes, seeds, nuts, whole grains, hard cheeses, and some nutritional supplements were found to be excellent sources of both zinc and copper. Vegetables, fruits, and their products were generally poor sources of trace minerals, with the exception of seed and bean sprouts. Milk and milk products, including rennetless cheeses, contain small quantities of these minerals. Although many of the foods consumed by vegetarians do contain adequate amounts of zinc and copper, their bioavailability may be limited.

Alterations in a series of anthropometric measurements taken on 142 vegetarian preschool children adhering to macrobiotic or other vegetarian regimens were studied. Length, subscapular skinfolds, and arm-muscle cirumferences differed from expectations. Dietary group and age, but not sex, were associated with these variations. Measurements were more likely to be depressed among children on a macrobiotic diet. Differences were significant among children twelve to thirty-five months of age for length and subscapular skinfolds and among children thirty-six months or older for arm circumference and subscapular skinfolds. Fewer vegetarian children were obese, and more were lean, than would be expected from norms.

The effect of a high-fat, high-beef diet and of method of preparation of beef in the diet on the fecal bile acids and neutral sterols and on the activities of fecal bacterial beta-glucuronidase, cholesterol dehydrogenase and 7 alpha-dehydroxylase was studied in healthy men and women, 24-41 years old, who were consuming a customary mixed-western diet. The experimental diets were high in fat and beef, which was cooked rare, medium or well-done. The sequence of dietary regimen was selected at random and each diet phase lasted for 4 weeks. Individual 24-hour fecal specimens were collected from each volunteer for the final 3 days during each dietary period, including pre- and post-experimental periods while they were consuming a customary mixed-western diet. The mode of cooking beef in the high-fat, high-beef experimental diets had no influence on the fat and protein content of the diets but the fat content of experimental diets was high compared to customary mixed-western diet. Fecal bacterial beta-glucuronidase activity and fecal secondary bile acid and cholesterol metabolite levels were significantly higher during the experimental diet periods but the fecal bacterial activities of 7 alpha-dehydroxylase and cholesterol dehydrogenase were unaffected. The mode of cooking beef in experimental diets had no influence on the fecal bacterial enzymes and on the excretion of fecal bile acids and cholesterol metabolites.

Twenty-four obese but otherwise normal men and women were followed for: Two weeks on their usual food intake; eight weeks on a high-protein, low-carbohydrate diet; and then again for two weeks on their usual diet. During this time, several metabolic parameters were measured bimonthly. The high-protein, low-carbohydrate dieting resulted in substantial weight loss, probably due to a combination of salt and water loss, as well as caloric restriction. Plasma triglycerides fell as well. Significant increases occurred in LDL-cholesterol, uric acid, and free fatty acid levels. HDL-cholesterol levels failed to rise despite significant weight loss, indicating that the previously reported relationship between HDL-cholesterol and weight may be dependent, in part, on the composition of the diet.

1. The effect of exercise on blood ketone body concentrations was studied in trained athletes and in sedentary subjects pedalling a bicycle ergometer. 2. Although the untrained subjects had higher heart rates and blood lactate concentrations at the same work load as the athletes, neither group developed ketonaemia even after intense or prolonged exercise. 3. Older subjects developed post-exercise ketonaemia, reaching maximum about 3 hr after exercise. 4. A high-carbohydrate diet before the exercise could prevent the onset of post-exercise ketonaemia and a low-carbohydrate diet enhanced it. The highest post-exercise blood ketone levels were recorded in marathon runners after a "glycogen-stripping' regimen. 5. Concentrations of free fatty acids, glucose, growth hormone and insulin in blood after exercise followed different patterns from that of ketones. 6. Post-exercise ketosis, when it occurs in untrained subjects, may be due to a lower carbohydrate intake than that of athletes.

Three-day dietary intakes were obtained on forty-eight preschool children between two and five years old, who had followed a vegetarian diet since birth. Intakes were calculated for food energy and selected nutrients. In addition, the children were measured for height, weight, triceps and subscapular skinfolds, and arm circumference. Average dietary intakes of the children compared favorably with the Recommended Dietary Allowances. Calcium was the only nutrient consumed in less than optimal amounts. Average intakes of the calculated amino acids were adequate when compared with available information. In general, anthropometric data were below the standards established by HANES findings, the National Center for Health Statistics, and available arm circumference data.