Published Science

For several decades representatives of Scandinavian health food movements have categorically recommended that victims of rheumatoid arthritis should switch to a vegetarian diet to obtain a cure for the disease. A very strict vegan diet (i.e., completely lacking in animal protein) is usually recommended, with certain features said to be particularly beneficial to rheumatic patients. These notions have been widely disseminated and have been adopted with remarkable faith by the public. Although a measure of support for the subjective palliative effects of a vegan diet has derived from certain medical studies, it should be borne in mind that, apart from exceptional cases, the inflammatory joint condition has persisted unabated; nor has the diet shown any tendency to forestall subsequent joint damage. More recent studies of the importance of various dietary factors vis-à-vis rheumatoid arthritis have to some extent improved our understanding of vegan diets, and shown there to be features of this type of diet which might contribute to the subjective improvement experienced by patients. The findings of such studies may provide a basis for speculation as to the form a more rational health food diet for rheumatic patients in the future.

Low or normal serum TSH concentration is common during fasting and in patients with anorexia nervosa. We report here four patients with anorexia nervosa who had elevated serum TSH, low T3 and low free T4 levels when the initial diagnosis was made. Also, an appearance of TSH peak in response to TRH was delayed, but T3 responsiveness to TRH was normal. All patients were clinically euthyroid with negative serum thyroid autoantibodies and without goiter. Following weight gain, basal levels of serum T3, free T4, and TSH, as well as TSH responsiveness to TRH, returned almost to normal. The data indicated that these patients with anorexia nervosa before refeeding had either a latent transient primary hypothyroidism or the low T3 syndrome associated with an inappropriately high secretion of TSH, probably a new condition that is related to their pretreatment nutritional state.

Between 1949 and 1984, 150 multiple sclerosis patients consumed low-fat diets. Fats, oils, and protein intakes; disability; and deaths were determined. On daily fat consumption of less than 20.1 g (average 17 g), 31% died and deterioration was slight. Daily intakes of greater than 20 g (average of either 25 or 41 g) were attended by serious disability and deaths of 79% and 81%, respectively. Oil intakes bore an indirect relationship to fat consumption. Treatment early and before severe disability developed improved prognosis, and females tended to do better than males. High sensitivity to fats suggests they are involved in the genesis of multiple sclerosis.

A case-control study of gastric cancer was done in a rural area of northern Kyushu, Japan, in relation to dietary habits especially focusing on the relationship with the consumption of broiled fish. The study was based upon 139 cases of newly diagnosed gastric cancer at a single institution, 2,574 hospital controls and 278 controls sampled randomly from the residents of the study area (with sex and year of birth matched). No association was observed between the consumption of broiled fish and gastric cancer risk whether three types of broiled fish (raw fish, dried fish and salted fish) were analyzed separately or as a single category. However, consistently in the comparisons with both sets of controls, the risk of gastric cancer was inversely related with the consumption of fruits and positively associated with cigarette smoking. A decreased risk of gastric cancer was also noted among those with high consumption of green tea (10 or more cups per day).

Post-exercise ketosis is not abolished by glucose ingestion immediately after exercise but is counteracted by simultaneous beta-adrenergic blockade. To investigate the effect of beta-adrenergic blockade on post-exercise ketosis without the ingestion of glucose, we administered propranolol (1 mg/kg body mass) to 15 carbohydrate-starved people, of whom five had just walked 9 km in 2 h. There were 43 control subjects (no propranolol). The blood concentration of 3-hydroxybutyrate rose from 0.18 +/- 0.02 (S.E.M.) mmol/l at 07.00 h to 0.35 +/- 0.04 mmol/l at 09.00 h whether the subjects had exercised during those 2 h or not (d.f. = 57). The blood concentration of 3-hydroxybutyrate at 15.00 h in the groups not treated with propranolol was not affected by exercise (0.95 +/- 0.90 mmol/l; d.f. = 42). Propranolol significantly raised the concentration of 3-hydroxybutyrate at 15.00 h to 1.68 +/- 0.26 mmol/l when given after exercise (d.f. = 4), but lowered it to 0.46 +/- 0.07 mmol/l in the non-exercised group (d.f. = 9). This was not accompanied by significant differences in the blood concentrations of glucose, free fatty acid, insulin or glucagon. The difference in response to propranolol administration is probably determined by the alanine and lactate flux from muscle for hepatic oxaloacetate synthesis.

To investigate the digestive kinetics and fiber digestion of great apes, we conducted digestion trials on chimpanzees (Pan troglodytes) with diets of two fiber levels, one containing 34% neutral detergent fiber (NDF) and the other 14% NDF. Chimpanzees exhibited a response to fiber similar to that of humans. First, increases in the fiber concentration of the diet decreased mean transit time (MTT), hindgut turnover time (T) and the digestibility of fiber. Second, differences in MTT and T between the treatments and animals explained most of the variability in the digestibility of fiber components. Third, consistent with human data, the fiber marker passed more slowly than the liquid marker only when the high fiber diet was consumed. Fourth, individual variability, as in humans, was a significant factor affecting digestion and passage. Fifth, the MTT of chimpanzees was longer than that of humans. This result may be due to the apes' larger hindgut. In comparison with other hominoids, humans have smaller volumes in the gastrointestinal tract and hindgut. The gut proportions of modern humans, in combination with evidence from the fossil record, indicate that during its evolution the human lineage was able to overcome nutritional constraints imposed on body size increases in the great apes. We suggest that this advance was achieved through technological and social innovations that permitted early humans to achieve larger body size without lowering dietary quality.

Gut Transit and Carbohydrate Uptake

To determine whether the high incidence of tuberculosis among Asiatic Indians in the United Kingdom was due to impaired killing of Mycobacterium tuberculosis by macrophages from patients deficient in cobalamin, a nutritional survey was carried out among 1187 Indians and the incidence of tuberculosis determined from medical records. The question asked was whether tuberculosis was significantly more common among life-long vegetarians compared with omnivores. The incidence of tuberculosis in vegetarians was 133 in 1000 and that in subjects on mixed diets 48 in 1000. These findings lend support to the hypothesis that dietary factors are of major importance in determining the susceptibility of Asiatic Indians to tuberculosis.

When normal volunteers ate isocaloric wheat-based meals, their plasma insulin responses (peak concentration and area under curve) increased stepwise: whole grains less than cracked grains less than coarse flour less than fine flour. Insulin responses were also greater with fine maizemeal than with whole or cracked maize grains but were similar with whole groats, rolled oats, and fine oatmeal. The peak-to-nadir swing of plasma glucose was greater with wheat flour than with cracked or whole grains. In vitro starch hydrolysis by pancreatic amylase was faster with decreasing particle size with all three cereals. Correlation with the in vivo data was imperfect. Oat-based meals evoked smaller glucose and insulin responses than wheat- or maize-based meals. Particle size influences the digestion rate and consequent metabolic effects of wheat and maize but not oats. The increased insulin response to finely ground flour may be relevant to the etiology of diseases associated with hyperinsulinemia and to the management of diabetes.

When normal volunteers ate isocaloric wheat-based meals, their plasma insulin responses (peak concentration and area under curve) increased stepwise: whole grains less than cracked grains less than coarse flour less than fine flour. Insulin responses were also greater with fine maizemeal than with whole or cracked maize grains but were similar with whole groats, rolled oats, and fine oatmeal. The peak-to-nadir swing of plasma glucose was greater with wheat flour than with cracked or whole grains. In vitro starch hydrolysis by pancreatic amylase was faster with decreasing particle size with all three cereals. Correlation with the in vivo data was imperfect. Oat-based meals evoked smaller glucose and insulin responses than wheat- or maize-based meals. Particle size influences the digestion rate and consequent metabolic effects of wheat and maize but not oats. The increased insulin response to finely ground flour may be relevant to the etiology of diseases associated with hyperinsulinemia and to the management of diabetes.

Plasma taurine levels and urinary taurine excretion were measured in 12 strict vegetarian (vegan) males who had maintained a vegan diet for 53 +/- 26 mo (SD) and in 14 male nonvegetarian control subjects. Plasma taurine levels differed (45 +/- 7 vs 58 +/- 16 mumol/L, respectively). Urinary taurine excretion was lower (266 +/- 279 vs 903 +/- 580 mumol/d), urinary N pi-methylhistidine was barely detectable, and urinary N tau-methylhistidine was significantly reduced (296 +/- 87 vs 427 +/- 19 mumol/d) in the vegans. Analysis of 3-d dietary diaries kept by the vegans indicated marginal to adequate intake of protein, carbohydrate, vitamin B-6, methionine, and cystine; inadequate intake of zinc; and negligible intake of taurine. Prolonged absence of dietary taurine intake causes decreased plasma taurine and severely restricted urinary taurine output.

A literature review was conducted using original papers published during 1964-1985 on the in vitro clastogenicity of chemical substances. Results of tests on 951 chemical substances were abstracted from over 240 reports to form the database. The evaluation of these data relied on each author's original conclusion on a positive or negative outcome. Of these 951 substances, 447 (47%) were consistently positive either with or without activation; 417 (44%) were negative in the direct test but not tested with metabolic activation systems; 4 were negative but tested only with activation; and 30 (3%) were clearly negative both with and without activation. The remaining 53 substances gave variable results when tested under different experimental protocols or in different cell types, but were positive in at least one test. Although discrepant results were found associated with some cell types, the addition of metabolic activation systems tended to eliminate such variability. No one cell appeared to be superior in response to all clastogens. For screening purposes, the choice of cell may thus depend more on the general usefulness and reliability of a cell type than on a strong response to a particular chemical. However, the use of a suitable metabolic activation system does appear to be of critical importance. The concentration at which clastogenic effects were detected varied extensively for different test substances, ranging from a minimum of 4.3 X 10(-8) to 6.9 X 10(2) mM. Possible mechanisms of action for substances active at only high levels are discussed, but no satisfactory explanation is available at this time. The relevance of tests conducted at concentrations high enough to alter significantly the osmolarity and other culture conditions is considered, and caution urged in the interpretation of test results obtained under physiologically stressful conditions. The clastogenic potential was compared quantitatively using an index of effective concentration (D20) and one which estimates the number of cells with exchange aberrations expected per mg/ml (TR) for data obtained by using a uniform protocol and cultures of Chinese hamster lung (CHL) cells. Both values were distributed over a wide range, demonstrating the variety of genotoxic potential in chemicals. In general, a substance which was active at only high concentrations produced fewer exchange-type aberrations. In vivo activity, as measured by tumourigenic effect and formation of micronuclei in bone marrow, tended to be greater for substances with a D20 below 10(-2) mg/ml and a TR value over 10(3).(ABSTRACT TRUNCATED AT 400 WORDS)

Food intake and feelings of hunger and fullness were monitored in paired studies carried out in two groups of six healthy non-obese male volunteers during infusion of isotonic solutions of either a 50% corn oil emulsion or saline into the jejunum or into the ileum. Infusion of the lipid emulsion at a rate of 1.2 ml/min (4.9 kcal/min) into either the ileum or the jejunum significantly reduced the period of eating (p less than 0.01) and the quantity of food consumed (p less than 0.01), but neither affected the rates of drinking or the amount of fluid consumed. Infusion of the lipid emulsion into the jejunum also significantly reduced the sensations of hunger before the meal (p less than 0.05), and the rate of ingestion (p less than 0.01). Ileal infusion did not influence these indices. The results suggest that jejunal and ileal infusion of lipid reduces the size of the meal that could be consumed possibly by inhibiting gastric emptying. The alleviation of hunger before ingestion and the slower rate of eating, however, suggests that jejunal lipid activates an additional mechanism that influences the appetite centre in the hypothalamus directly.

Multiple food allergies required a group of seven patients with elevated serum cholesterol levels to follow a diet in which most of the calories came from beef fat. Their diets contained no sucrose, milk, or grains. They were given nutritional supplements. This is the only group of people in recent times to follow such a diet. During the study, the patients' triglyceride levels decreased from an average of 113 mg/dl to an average of 74 mg/dl; at the same time, their serum cholesterol levels fell from an average of 263 mg/dl to an average of 189 mg/dl. At the beginning of the study, six of the patients had an average high-density lipoprotein percentage of 21%. At the end of the study, the average had risen to 32%. These findings raise an interesting question: are elevated serum cholesterol levels caused in part not by eating animal fat (an extremely "old food"), but by some factor in grains, sucrose, or milk ("new foods") that interferes with cholesterol metabolism?

We wished to determine whether different types of dietary protein might have different effects on calcium metabolism and on the propensity for renal stone formation. Fifteen young normal subjects were studied during three 12-day dietary periods during which their diet contained vegetable protein, vegetable and egg protein, or animal protein. While these three diets were constant with respect to Na, K, Ca, P, Mg, and quantity of protein, they had progressively higher sulfur contents. As the fixed acid content of the diets increased, urinary calcium excretion increased from 103 +/- 15 ( +/- SEM) mg/day (2.6 +/- 0.4 mmol/day) on the vegetarian diet to 150 +/- 13 mg/day (3.7 +/- 0.3 mmol/day) on the animal protein diet (P less than 0.02). Despite the increased urinary calcium excretion, there was a modest reduction of urinary cAMP excretion and serum PTH and 1,25-dihydroxyvitamin D levels consistent with acid-induced bone dissolution. There was no change in fractional intestinal 47Ca absorption. The inability to compensate for the animal protein-induced calciuric response may be a risk factor for the development of osteoporosis. The animal protein-rich diet was associated with the highest excretion of undissociated uric acid due to the reduction in urinary pH. Moreover, citrate excretion was reduced because of the acid load. However, oxalate excretion was lower than during the vegetarian diet [26 +/- 1 mg/day (290 +/- 10 mumol/day) vs. 39 +/- 2 mg/day (430 +/- 20 mumol/day); P less than 0.02]. Urinary crystallization studies revealed that the animal protein diet, when its electrolyte composition and quantity of protein were kept the same as for the vegetarian diet, conferred an increased risk for uric acid stones, but, because of opposing factors, not for calcium oxalate or calcium phosphate stones.

The results reveal that, among children with similar physician-evaluated health, low levels of acculturation are associated with greater discrepancies between mothers and physicians and higher levels of acculturation with greater agreement.

Vegan children often fail to grow as well as their omnivorous cohorts despite protein intakes that exceed RDA. Explanations for inadequate growth include deficiencies of energy, calcium, zinc and vitamins B-12 and D. Due to decreased bioavailability, amino acids and nitrogen in vegan diets may be inadequate to support normal growth. Bioavailability of amino acids and nitrogen may be decreased by dietary fiber, food processing and storage, inadequate energy, and other unknown factors. Bioavailability should be considered when evaluating adequacy of intakes of protein, amino acids and nitrogen from vegan diets by infants and children.

Images null

Underlying any successful counseling effort must be an understanding of the acceptable and unacceptable foods of the particular person being counseled, with the recognition that nutrient needs may be met in many ways. This knowledge base necessary for successful counseling along with an understanding of other lifestyle practices that may have an impact on health will be difficult to develop unless rapport is established. Nonjudgmental, accepting attitudes on the part of the health professional are essential to the development of relationships with those individuals who may be suspicious of traditional medical and health-care practices. Strategies for counseling with particular attention to the vegetarian are noted.

Fourteen patients with rheumatoid arthritis (RA) were studied before, during, and after a 1-week total fast. Disease activity decreased, as did the neutrophil release of lysozyme induced by the ionophore A23187. The ability of zymosan-activated RA patient serum to aggregate control neutrophils was reduced, together with serum concentrations of C3. The relative contents of arachidonic acid and eicosapentaenoic acid were increased in serum, platelets, and neutrophils, whereas levels of linoleic acid and linolenic acid were unchanged. Fasting also reduced the release of leukotriene B4 from neutrophils. We thus conclude that a reduced ability to generate cytotaxins, reduced release of enzyme, and reduced leukotriene formation from RA neutrophils, together with an altered fatty acid composition of membrane phospholipids, may be mechanisms for the decrease of inflammatory symptoms that results from fasting.

Studies in man have shown that the episodic release of growth hormone (GH) is infrequent and erratic, and unlike that in the rat does not appear to have discernible ultradian periodicities. However, these observations in nonfasted subjects may be invalid since mixed nutrients have unpredictable effects on GH release. Moreover, in the fed state basal GH levels are frequently undetectable, thus rendering the identification of low amplitude pulses unreliable. Accordingly, the 24-h pulsatile pattern of GH secretion obtained from repetitive venous sampling in six normal adult male subjects was examined during a control fed day and during the first and fifth days of a 5-d fast. The GH data were analyzed using two distinct methods: a discrete pulse detection algorithm (Cluster analysis) and Fourier expansion time-series, which allows fixed periodicities of secretory activity to be resolved. The 5-d fast resulted in a significant increase in discrete GH pulse frequency (5.8 +/- 0.7 vs. 9.9 +/- 0.7 pulses/24 h, P = 0.028), 24 h integrated GH concentration (2.82 +/- 0.50 vs. 8.75 +/- 0.82 micrograms.min/ml; P = 0.0002), and maximal pulse amplitude (5.9 +/- 1.1 vs. 12.3 +/- 1.6 ng/ml, P less than 0.005). While multiple low-amplitude sinusoidal periodicities were present on the control fed day, time-series analysis revealed enhancement of circadian and ultradian cycles on the first and fifth days of fasting. Concomitantly, fasting resulted in a decline (day 1 vs. day 5) in serum concentrations of somatomedin C (1.31 +/- 0.22 vs. 0.77 +/- 0.18 U/ml) and glucose (4.9 +/- 0.2 vs. 3.2 +/- 0.2 mmol/liter), and a marked rise in free fatty acid (0.43 +/- 0.12 vs. 1.55 +/- 0.35 mmol/liter) and acetoacetate (35 +/- 6 vs. 507 +/- 80 nmol/liter). We conclude that the acute nutritional status is an important determinant of spontaneous pulsatile GH secretion in man. Fast-induced enhancement of GH release is achieved through combined frequency (discrete pulses) and amplitude (sinusoidal periodicities) modulation. Such alterations in somatotropic hormone release may play an important role in substrate homeostasis during starvation.

Special consideration must be given to providing key risk nutrients in planning food guides for vegetarians especially if the diet chosen excludes all animal products, such as dairy foods and eggs. The practical use of food guides for education is also important. Several food guides for adult vegans, including pregnant vegan women, were analyzed by computer for nutritional adequacy using 7-d menus and comparisons were made with the RDA for energy, protein, iron, calcium, and riboflavin. Several patterns were identified that supply the RDA for protein, iron, calcium, and riboflavin and have educational merit. None of the patterns provide sufficient energy to meet the RDA.

The growth and development of children born of vegan mothers and reared on a vegan diet has been studied longitudinally: All of the children were breast-fed for the first 6 mo of life and in most cases well into the second year of life. The majority of children grew and developed normally but they did tend to be smaller in stature and lighter in weight than standards for the general population. Energy, calcium, and vitamin D intakes were usually below the recommended amounts. Their diets, however, were generally adequate but a few children had low intakes of riboflavin and vitamin B-12. Most parents were aware of the need to supplement the diet with vitamin B-12. It is concluded that provided sufficient care is taken, a vegan diet can support normal growth and development.

Binding of herpes simplex virus (HSV) type 1 to the various subclasses of human serum lipoproteins was investigated. Studies were performed with human serum lipoproteins purified by differential ultracentrifugation and artificial proteoliposomes containing only one type of apolipoprotein (A1, E) by using an enzyme-linked immunosorbent assay technique, column chromatography, and electron microscopy. All tested lipoprotein subclasses (very low, low-, high-density lipoproteins; VLDL, LDL, HDL, HDL1) showed significant binding of purified HSV type 1. Furthermore, HSV bound to all different synthetic proteoliposomes. Adsorption of envelope proteins isolated from purified HSV to Sepharose-bound lipoproteins revealed binding of HSV glycoprotein B. Based on these results we reached the conclusion that in HSV-lipoprotein complex formation the lipid component in the lipoproteins and the glycoprotein B in HSV are the preferential reaction partners.

The bioavailability of a number of minerals may be altered by the special characteristics of vegetarian diets. Concern has centered on both inadequate and high dietary levels of specific minerals as well as reduced bioavailability because of a variety of dietary components. The possibility that plant-based diets may compromise mineral status is briefly reviewed for the following minerals: zinc, calcium, iron, manganese, selenium, and copper.

In diabetic patients, hyperglycaemia results in the non enzymatic glycation of many proteins including apolipoprotein A-I. We purified glycated apo A-I and compared its lipid binding properties to those of normal apo A-I. Analysis of tryptophan fluorescence spectra and of fluorescence quenching in the presence of iodine showed that glycation of apo A-I induces a decrease in the stability of the lipid-apoprotein interaction and in that of the apoprotein self-association. Repetitive ultracentrifugations of High Density Lipoprotein (HDL) samples containing radioiodinated apo A-I or glycated apo A-I revealed that glycation of the apoprotein facilitates its dissociation from HDL. These results suggest that the non enzymatic glycation of apo A-I may affect the structural cohesion of HDL particles. © 1988 Academic Press, Inc.

Production and service of quantity vegetarian meals requires skills that are used in most quantity food kitchens around the world. Menu planning with the vegetarian in mind requires the substitution of meat, fish, and poultry entrees with vegetable sources of protein. Variety of available alternatives is good in many locations; creativity in selecting alternatives contributes to excitement in meals and improved nutrition. Specific protein sources appropriate for quantity feeding include many ethnic foods as well as standard North American and Western European favorites that may require slight modifications. The computer plays a role in monitoring nutritional quality of menus served to customers. Other computer applications provide feedback for cost analysis and control of menu, inventory, and production planning. Research in production times of vegetarian entrees provides a basis for comparison of production times of menu items for cost analysis.

Concentrations of immunoreactiveβ-endorphin (irβ-E), corticotropin, cortisol, prolactin and catecholamines in plasma were followed in 11 healthy women during and after exposure to intense heat in a Finnish sauna bath, and compared to those in a similar control situation without exposure to heat. Heat stress significantly increased prolactin and norepinephrine secretion; the percentage increases from the initial plasma concentrations varied from 113 to 1280% (mean 510%) and from 18 to 150% (mean 86%), respectively. The response of the plasma levels of epinephrine, irβ-E, corticotropin and cortisol to heat exposure was variable. Compared to the control situation, no statistically significant effect of heat exposure on the plasma levels of these hormones was found.

Resistance to insulin-stimulated glucose uptake is present in the majority of patients with impaired glucose tolerance (IGT) or non-insulin-dependent diabetes mellitus (NIDDM) and in approximately 25% of nonobese individuals with normal oral glucose tolerance. In these conditions, deterioration of glucose tolerance can only be prevented if the beta-cell is able to increase its insulin secretory response and maintain a state of chronic hyperinsulinemia. When this goal cannot be achieved, gross decompensation of glucose homeostasis occurs. The relationship between insulin resistance, plasma insulin level, and glucose intolerance is mediated to a significant degree by changes in ambient plasma free-fatty acid (FFA) concentration. Patients with NIDDM are also resistant to insulin suppression of plasma FFA concentration, but plasma FFA concentrations can be reduced by relatively small increments in insulin concentration. Consequently, elevations of circulating plasma FFA concentration can be prevented if large amounts of insulin can be secreted. If hyperinsulinemia cannot be maintained, plasma FFA concentration will not be suppressed normally, and the resulting increase in plasma FFA concentration will lead to increased hepatic glucose production. Because these events take place in individuals who are quite resistant to insulin-stimulated glucose uptake, it is apparent that even small increases in hepatic glucose production are likely to lead to significant fasting hyperglycemia under these conditions. Although hyperinsulinemia may prevent frank decompensation of glucose homeostasis in insulin-resistant individuals, this compensatory response of the endocrine pancreas is not without its price. Patients with hypertension, treated or untreated, are insulin resistant, hyperglycemic, and hyperinsulinemic. In addition, a direct relationship between plasma insulin concentration and blood pressure has been noted. Hypertension can also be produced in normal rats when they are fed a fructose-enriched diet, an intervention that also leads to the development of insulin resistance and hyperinsulinemia. The development of hypertension in normal rats by an experimental manipulation known to induce insulin resistance and hyperinsulinemia provides further support for the view that the relationship between the three variables may be a causal one.(ABSTRACT TRUNCATED AT 400 WORDS)

It continues to be generally accepted that the iconoclastic research work of Professor Thomas McKeown and associates conclusively demonstrated that the medical establishment—including all the efforts of the public health movement—played only a minor role in the grand historical and demographic drama of the period, the secular decline in national mortality levels. According to McKeown's apparently authoritative analysis and interpretation of the available epidemiological statistics, the mortality decline in England and Wales can be primarily accounted for by the benevolent 'invisible hand' of gradually rising living standards, particularly in the form of increases in per capita nutritional consumption. The coherence of this view is brought into question by a critical re-examination of the supporting evidence and arguments presented by McKeown el al. It is anticipated that for many of those not closely acquainted with the 'McKeown thesis', the fragility of the case may come as something of a surprise. An alternative interpretation of the same epidemiological evidence then forms the basis for a revisionist account which directs attention to the leading role played by the public health movement and its locally administered preventive health measures in combating the urban congestion created by industrialization.

Serial blood samples were taken at two-hour intervals over a 24-hour period from 25 premenopausal vegetarians (12 vegans and 13 ovolactovegetarians) and from 21 omnivorous controls. All members of the former group had been on a vegetarian diet for a minimum of three years. The mean proportion of estradiol unbound to blood proteins was similar in both vegetarians (1.26%) and meat eaters (1.16%). However, the amount bound to albumin was significantly raised in vegetarians (50.1% vs. 43.1%, p less than 0.009), whereas that bound to sex hormone-binding globulin (SHBG) was correspondingly lower (48.7% vs. 55.8%, p = 0.01). Mean levels of SHBG were similar in vegetarians (59.9 nmole/l) and omnivores (62.0 nmole/l), as was the total amount of free fatty acid (0.42 mmole/l for both). Within the vegetarian group, no differences were detected between vegans and ovolactovegetarians.

Acceptable and appropriate vegetarian diets fulfill the Recommended Dietary Allowances and other authoritative dietary guidelines dealing with balance, variety, moderation, and developmental appropriateness of diets for children. Vegetarian regimes currently fed to infants and children are evaluated using these criteria. Vegan-like diets, fed early in infancy and childhood, pose special problems with respect to sufficiency of certain nutrients, energy, and bulk, especially if they are unplanned and unaccompanied by ongoing health supervision. Lactovegetarian, lactoovovegetarian, and semivegetarian patterns are more likely to be satisfactory. They conform closely with the pediatric recommendations for promoting health and reducing risks of chronic degenerative diseases, are sufficient without being excessive in nutrients, are low in bulk, and are developmentally appropriate.

Evidence that nutrients other than the major cations may influence blood pressure levels stems from studies of acculturated vegetarians and from randomized controlled dietary trials. Earlier studies of vegetarians focused on religious groups and on vegans, making it difficult to know whether their lower blood pressures were due to diet per se or to other aspects of lifestyle. Seventh-day Adventist vegetarians showed significantly less hypertension and lower blood pressures compared with Mormon omnivores, effects which were independent of differences in obesity and not due to altered sodium intake. Subsequently, controlled dietary intervention studies in healthy normotensive omnivores provided more direct evidence for a blood pressure-lowering effect of a lactoovovegetarian diet with reversible changes of 5-6 mm Hg systolic and 2-3 mm Hg diastolic occurring over 6-wk periods. Similar dietary effects in mild hypertensive subjects provides impetus for identifying the responsible nutrients.

Recently, a relatively small reduction in systolic blood pressure (approximately 5 mm Hg) was estimated to substantially reduce the numbers of major coronary events. The blood pressure reduction is about the same as the difference seen between typical ovolactovegetarians and omnivores. This paper reviews the evidence for the blood pressure-lowering effects of a vegetarian diet on those with elevated blood pressure. It also reviews whether the effect on blood pressure of a vegetarian diet can be attributed either to elevation of the dietary P:S ratio or to fiber intake alone.

Confounding influences of varying fat, protein, and carbohydrate (CHO) levels, training habits, and lifestyle patterns make the interpretation of specific influences of the diet on endurance performance unclear. In general, exhaustion during prolonged, hard endurance exercise is tied to low muscle glycogen stores. Athletes in heavy training are urged to consume 70% of calories as CHO to maximize body CHO stores. A deemphasis in animal products with an emphasis in high-CHO plant foods would facilitate athletes in conforming to nutritional recommendations. Some female athletes may increase their risk of iron deficiency and/or amenorrhea if a restrictive vegetarian diet is adopted. In general, the high-CHO nature of the vegetarian diet can help the endurance athlete in heavy training maximize body glycogen stores and thus the ability to perform. The balanced vegetarian diet provides the athlete with added reduction in coronary risk factors while meeting all known nutritional needs.

The amount and type of dietary protein affect bone mineral loss after the menopause. This observation was substantiated in 10 y of studies by direct photon absorptiometry, four results of which follow. 1) Studies of 1600 women in southwestern Michigan revealed that those who had followed the lactoovovegetarian diet for at least 20 y had only 18% less bone mineral by age 80 whereas closely paired omnivores had 35% less bone mineral. 2) A study of self-selected weighed food intake showed no statistical difference in nutrient intakes but a difference in Ca:P ratio and acid-base formation of diet, each significant to p less than 0.001. 3) When sulfur intake of a fixed diet was increased, the titratable acidity of the urine increased proportionately. 4) Bone mineral densities of 304 older women from the continental United States closely paralleled those from earlier Michigan studies.

Birth in most mammalian species represents an abrupt change from a high-carbohydrate and low-fat diet to a high-fat and low-carbohydrate diet. Gluconeogenesis is absent from the liver of the fetus of well-fed mothers, but can be induced prematurely by prolonged fasting of the mother. Gluconeogenesis increases rapidly in the liver of newborn mammals in parallel with the appearance of phosphoenolpyruvate carboxykinase (PEPCK), the rate-limiting enzyme of this pathway. The rise in plasma glucagon and the fall in plasma insulin which occur immediately after birth are the main determinants of liver PEPCK induction. When liver PEPCK has reached its adult value, i.e. 24 h after birth, other factors are involved in the regulation of hepatic gluconeogenesis. In order to maintain a high gluconeogenic rate, the newborn liver must be supplied with sufficient amount of gluconeogenic substrates and free fatty acids. An active hepatic fatty acid oxidation is necessary to support hepatic gluconeogenesis by providing essential cofactors such as acetyl CoA and NADH. The relevance of animal studies for the understanding of neonatal glucose homeostasis in man is discussed.

In a metabolic ward 12 healthy male subjects consumed mixed Western (M), lacto-ovovegetarian (L), and vegan (V) diets in a randomized order for 20 d each. The concentrations of deoxycholic acid, isolithocholic acid, and total bile acids in 4-d composites of feces on the L and V diets were significantly lower than on the M diet. The chenodeoxycholic-to-isolithocholic plus lithocholic acid ratio was significantly higher on the V diet. The concentrations of coprostanol and of coprostanol plus cholesterol were highest on M diet and lowest on V diet. The number of fecal lactobacilli and enterococci on the V diet was significantly lower than on the M or the L diets. This study showed a decrease in the concentration of fecal (secondary) bile acids by the L and the V diets and an alteration of the fecal flora composition by the V diet.