Published Science

The stable carbon and nitrogen isotope composition of bone collagen has been determined for 238 modern non-human mammals, comprising 43 species of herbivores and carnivores from grasslands and montane forests in Kenya and Tanzania, and 97 historic and prehistoric humans, representing 12 populations with different dietary adaptations from eastern and southern Africa. Among non-human species carbon isotope ratios separate grazers from browsers in open grasslands, forest floor from forest canopy, and forest floor from open grassland feeders. Nitrogen isotopes separate carnivores from herbivores and forest from savanna-living species. Water-dependent herbivores have lower nitrogen isotope ratios than drought-tolerant ones in the same habitat. Among human populations, carbon isotopes differentiate those who regularly consume grains and/or the protein of browsing animals from those who consume wild plants, non-grain crops and/or the protein of wild animals. Nitrogen isotopes differentiate those dependent on the milk, meat and blood of domestic animals or marine resources from those dependent mainly on plant foods. Combined use of carbon and nitrogen isotopes permits the differentiation of pastoralists from farmers, camel pastoralists from capri-bovine pastoralists, and grain farmers from non-grain farmers. The apparent presence of physiological and climatic influences on nitrogen isotope ratios within trophic levels complicates dietary interpretations of variations in nitrogen isotope ratios but may also offer a new tool of climatic reconstruction. It shoudl nonetheless be possible to use the analysis of the isotopic composition of bone collagen as a quantitative technique for the reconstruction of diet, habitat selection, climate and water balance in prehistoric animal and human communities, and to test models that suggest dietary adaptations were prime movers of hominid biological and cultural evolution.

In a blind, placebo-controlled study of dietary manipulation therapy in outpatients with rheumatoid arthritis there was significant objective improvement during periods of dietary therapy compared with periods of placebo treatment, particularly among "good responders". Possible explanations for improvement include reduced food intolerance, reduced gastrointestinal permeability, and benefit from weight loss and from altered intake of substrates for prostaglandin production. A proportion of the improvement was due to a placebo response, but this was not sufficient to explain the whole improvement.

138 Indian patients with megaloblastic haemopoiesis were studied. All were lifelong vegetarians. The diagnosis was nutritional cobalamin deficiency in 95 and pernicious anaemia in 20; only 4 patients had folate deficiency. A third had intestinal malabsorption, 20 had features of osteomalacia, and 87 were iron deficient. Tuberculosis was diagnosed in 17. Cobalamin deficiency may have contributed to these complications via intestinal malabsorption and impaired bacterial killing of phagocytosed bacilli by cobalamin-deficient macrophages. The frequency of pernicious anaemia was the same in Indian subjects as in Caucasians.

Abstract. The relationship between dietary nutrients and plasma testosterone, 5α-dihydrotestosterone, estradiol-17β, luteinizing hormone, and prolactin levels

Abstract. The relationship between dietary nutrients and plasma testosterone, 5α-dihydrotestosterone, estradiol-17β, luteinizing hormone, and prolactin levels

Cheeke, Peter R.

We examined 42 Rastafarian children under 5 years of age who were registered with a single inner city general practice to determine the prevalence of nutritional rickets. Twenty children were receiving a strict vegan(I-tal) diet and were considered to be at high risk of developing rickets and were referred for biochemical and radiological investigation. Seven of 20 children investigated had rickets, giving an overall prevalence of 7/42. Treatment with oral cholecalciferol was successful in all seven children. Fourteen out of 18 children had evidence of iron deficiency, with low haemoglobin concentrations and hypochromic-microcytic blood films. Before this study Rastafarian children rarely attended the well baby clinic, received no vitamin supplements, and few had been immunised. They now regularly attend the clinic, receive vitamin and iron supplements, and all have completed primary immunisation.

Type II diabetic subjects were given 50 g protein, 50 g glucose, or 50 g glucose with 50 g protein as a single meal in random sequence. The plasma glucose and insulin response was determined over the subsequent 5 h. The plasma glucose area above the baseline following a glucose meal was reduced 34% when protein was given with the glucose. When protein was given alone, the glucose concentration remained stable for 2 h and then declined. The insulin area following glucose was only modestly greater than with a protein meal (97 ± 35, 83 ± 19 µU · h/ml, respectively). When glucose was given with protein, the mean insulin area was considerably greater than when glucose or protein was given alone (247 ± 33 µU · h/ml). When various amounts of protein were given with 50 g glucose, the insulin area response was essentially first order. Subsequently, subjects were given 50 g glucose or 50 g glucose with 50 g protein as two meals 4 h apart in random sequence. The insulin areas were not significantly different for each meal but were higher when protein + glucose was given. After the second glucose meal the plasma glucose area was 33% less than after the first meal. Following the second glucose + protein meal the plasma glucose area was markedly reduced, being only 7% as large as after the first meal. These data indicate that protein given with glucose will increase insulin secretion and reduce the plasma glucose rise in at least some type II diabetic persons.

Fifty-four episodes of predatory behavior of wild chimpanzees were recorded in Mahale, western Tanzania, from August 1979 to May 1982. The chimpanzees most frequently hunt in two seasons, during May, and from August to December. Longer-term fecal analysis indicates that predation frequency is significantly higher in the dry than in the rainy season. The seasonality of predation might be the result of the sum of various ecological factors, at least one of which is the birth season of the prey species. Most of the prey are juvenile blue duiker, bushbuck, bushpig, red colobus, and red-tailed monkeys. Sex difference is recognized in the prey selection and in the hunting method employed. Apparent local difference in the predatory behavior between Mahale and Combe chimpanzees (in Mahale,females hunt more frequently, and blue duiker is the most frequent prey) can be understood in terms of the difference either in the observation methods or in the faunal diversity and density. Other aspects of predatory behavior also are reported.

Dietary self-selection and circulating metabolic fuels (glucose, free fatty acids, ketones) were examined in three forms of experimental diabetes mellitus in rats: pancreatectomy and streptozotocin treatment in adult and neonatal rats. Changes in diet selection resulting from insulin replacement also were examined. Differences were found in diet selection and circulating metabolic fuels between these types of diabetes. Mildly diabetic rats selected large amounts of fat while more severely diabetic rats primarily selected protein. Insulin treatment enhanced carbohydrate intake of diabetic rats and nearly normalized diet selection and circulating metabolic fuels. All diabetic groups exhibited severe glucose intolerance. These results support the observations of the beneficial effects of low-carbohydrate diets, question the generality of the use of high-fat diets, and suggest a more important role for high-protein diets in energy regulation in severely diabetic rats.

Nine healthy subjects taking an average mixed "Western" diet were placed on a vegetarian diet poor in arachidonic acid for four weeks. All animal and marine foods except for cows milk and milk products were excluded. Platelet aggregation responses to arachidonic acid and epinephrine increased slightly whereas responses to ADP and collagen were unchanged. Platelet thromboxane production, platelet counts, serum LDL cholesterol and triglycerides did not change but total and HDL serum cholesterol levels fell significantly. There was a significant rise in platelet arachidonic acid content but other platelet fatty acids did not change significantly. A reduction in dietary arachidonic acid did not inhibit platelet aggregation or thromboxane production.

When lipoprotein [a] was isolated in the presence of the proteolytic inhibitor Trasylol, its apoprotein exhibited one dominant band corresponding to a molecular weight of about 1.2 million when analyzed by electrophoresis on 3.25% sodium dodecyl sulfate-polyacrylamide gels. After chemical reduction, this band was missing but was replaced by two bands, one corresponding to a molecular weight of about 490,000 and the other to a molecular weight of about 645,000. Before treatment with reducing agents, the apolipoprotein [a] and apolipoprotein B immunoreactivities were detectable in the same electrophoretic band, but after reduction the apolipoprotein [a] was demonstrated to be separate from the apolipoprotein B. These results suggest that the apoprotein of lipoprotein [a] is composed of two subunits which are similar in molecular weight and are held together by one or more disulfide bonds. One subunit possesses apolipoprotein [a] and the other apolipoprotein B immunoreactivity. The secondary structure of the apoprotein components within lipoprotein [a] has been studied by circular dichroism and found to differ significantly from the secondary structure of the apoproteins in low density lipoproteins and high density lipoproteins. About 30% alpha-helical structure was measured in lipoprotein [a] compared to 48% in low density lipoproteins and 70% in high density lipoproteins. Lipoprotein [a] exhibited a much higher percentage of disordered structure than either of the other two lipoproteins.

During late winter and spring, hunter-gatherers in temperate, subarctic, and arctic environments often relied on diets that provided marginal or inadequate caloric intakes. During such periods, particularly when stored food supplies dwindled or were used up entirely, lean meat became the principal source of energy. Nutritional problems associated with high-protein, low-energy diets are discussed. These problems include elevated metabolic rates, with correspondingly higher caloric requirements, and deficiencies in essential fatty acids. The relative benefits of adding fat or carbohydrate to a diet of lean meat are evaluated in light of the protein-sparing capacities of these two nutrients. Experimental data indicate that although both enhance high-protein, low-energy diets, carbohydrate is a more effective supplement than fat. Given the nutritional inadequacies of a lean-meat diet, the paper concludes with a discussion of alternative subsistence strategies that increase the availability of carbohydrate or fat at the critical time of year.

To evaluate the short-term effects of an intervention that consists of stress management training and dietary changes in patients with ischemic heart disease (IHD), we compared the cardiovascular status of 23 patients who received this intervention with a randomized control group of 23 patient who did not. After 24 days, patients in the experimental group demonstrated a 44% mean increase in duration of exercise, a 55% mean increase in total work performed, somewhat improved left ventricular regional wall motion during peak exercise, and a net change in the left ventricular ejection fraction from rest to maximum exercise of +6.4%. Also, we measured a 20.5% mean decrease in plasma cholesterol levels and a 91.0% mean reduction in frequency of anginal episodes. In this selected sample, short-term improvements in cardiovascular status seem to result from these adjuncts to conventional treatments of IHD.

59 healthy, omnivorous subjects aged 25-63 years were randomly allocated to a control group, which ate an omnivorous diet for 14 weeks, or to one of two experimental groups, whose members ate an omnivorous diet for the first 2 weeks and a lacto-ovo-vegetarian diet for one of two 6-week experimental periods. Mean systolic and diastolic blood pressures did not change in the control group but fell significantly in both experimental groups during the vegetarian diet and rose significantly in the experimental group which reverted to the omnivorous diet. Adjustment of the blood-pressure changes for age, obesity, heart rate, weight change, and blood pressure before dietary change indicated a diet-related fall of some 5-6 mm Hg systolic and 2-3 mm Hg diastolic. Although the nutrient(s) causing these blood-pressure changes are unknown, the effects were apparently not mediated by changes in sodium or potassium intake.

We studied 10 vegetarian and 10 nonvegetarian premenopausal women on four occasions approximately four months apart. During each study period, the participants kept three-day dietary records, and estrogens were measured in plasma, urinary, and fecal samples. Vegetarians consumed less total fat than omnivores did (30 per cent of total calories, as compared with 40 per cent) and more dietary fiber (28 g per day, as compared with 12 g). There was a positive correlation between fecal weight and fecal excretion of estrogens in both groups (P less than 0.001), with vegetarians having higher fecal weight and increased fecal excretion of estrogens. Urinary excretion of estriol was lower in vegetarians (P less than 0.05), and their plasma levels of estrone and estradiol were negatively correlated with fecal excretion of estrogen (P = 0.005). Among the vegetarians the beta-glucuronidase activity of fecal bacteria was significantly reduced (P = 0.05). We conclude that vegetarian women have an increased fecal output, which leads to increased fecal excretion of estrogen and a decreased plasma concentration of estrogen.

The lipogenic capacity of rat liver is increased in animals fed a high carbohydrate, fat-free diet or by the administration of 2,2',5'-triiodo-L-thyronine. Underlying this change is a generalized induction of the enzymes involved in lipogenesis, including glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and malic enzyme, which together serve to generate the additional NADPH required for increased fatty acid synthesis. This report presents evidence indicating that induction of the hexose-shunt dehydrogenases involves increased enzyme synthesis secondary to elevated enzyme specific mRNA levels, as has previously been shown for malic enzyme. Activities of specific mRNAs, estimated by cell-free translation of hepatic poly(A)-containing RNA in the mRNA dependent rabbit reticulocyte lysate, were compared with enzyme specific activities and relative rates of specific enzyme synthesis. The 2-fold increase in glucose-6-phosphate dehydrogenase specific activity in hyperthyroid rats and the 13-fold increase in rats fed a high carbohydrate, fat-free diet, relative to euthyroid, chow-fed controls were paralleled by comparable increases in the synthetic rates and mRNA levels of this enzyme. Similarly, consonant changes in the rate of enzyme synthesis and concentration of 6-phosphogluconate dehydrogenase mRNA accompanied the 2.5- and 3-fold increases in specific activity of this enzyme observed in response to hormonal and dietary induction, respectively. Thus, both thyroid hormone and carbohydrate feeding appear to induce glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase primarily by increasing the effective cellular concentrations of their respective mRNAs and, consequently, their rates of synthesis.

Thirty-eight species of free-living non-human primates, representing nine families, have been observed to hunt and/or eat vertebrates. Thirty-two per cent of these are prosimians, and 68% are arboreal forest-dwellers. The predation pattern involving the search for, and pursuit, capture and consumption of prey is rarely exhibited in nonhuman primates other than chimpanzees and baboons. Scavenging among non-human primates is uncommon. Only baboons and chimpanzees are known to stalk their prey, to hunt co-operatively and to share meat, and only chimpanzees have been observed to kill their prey by flailing and to carry meat. Man is the only primate that hunts animals larger than himself, and that incorporates tool-use, complex vocal communication and bipedalism into his hunting pattern. It is concluded that: (1) hunting of vertebrates is widespread but infrequent among free-living nonhuman primates, (2) search for, and pursuit, killing and eating of vertebrates was probably practised by early primates, and (3) there are several similarities between the hunting patterns of man and non-human primates but also several important differences.

Ophidine (β-alanyl-3-methylhistidine) was first detected in the urine of two patients and later in two members of the laboratory staff loaded with whale meat, by column chromatography, high-voltage paper electrophoresis and two-dimensional paper chromatography. The ophidine peak was detected between homocarnosine and dimethylarginine using a lithium buffer gradient in column chromatography. In paper chromatography the ophidine spot was detected at a position close to anserine and homocarnosine. The ophidine in the urine from the patients was of dietary origin since it was absent in the urine a few weeks later.

The serum levels of cholesterol bound to high density lipoproteins (HDL-C) were determined by the heparin-manganese chloride precipitation method in 306 subjects, 182 male with ages ranging from 11 to 81 years, and 124 female with ages ranging from 7 to 78 years. Twenty six subjects belonged to a lacto-vegetarian community, while the remaining 280 were healthy volunteers, factory workmen sampled during a regular check-up, and either outpatients or inpatients being evaluated for minor illnesses or minor surgery. None of the subjects had arteriosclerosis or a metabolic disease and, with the exception of the lacto-vegetarians, they were all consuming a normal diet. HDL-C concentrations varied very little among the different age groups. Females had HDL-C values slightly superior to those of males. No significant differences were found between smokers and non-smokers, alcohol drinkers and non-drinkers, and regularly exercising and sedentary people. HDL-C concentrations were independent of total cholesterol and triglyceride levels. Females under oral contraceptive treatment had lower HDL-C levels than control females, but the differences were not statistically significant. Compared with age and sex-matched controls, the lactovegetarians showed similar HDL-C concentrations.

The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ15N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ15N values. The variability of the relationship between the δ15N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in 15N relative to the diet, with the difference between the δ15N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ15N values ofcollagen and chitin. biochemical components that are often preserved in fossil animal remains, are also related to the δ15N value of the diet. The dependence of the δ15N values of whole animals and their tissues and biochemical components on the δ15N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ15N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ15C and δ15N values of bone collagen suggest that C4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

Aflatoxin-producing fungi were found in fermented foods and beverages: fermented rice (kaomak), soybean sauce (taotjo), peanut butter, soy sauce (shoyu), Thai red and white wine, and rice sugar wine. These foods were extracted directly and tested for aflatoxins by thin-layer chromatography (TLC) and high pressure liquid chromatography (HPLC). Four strains of aflatoxin-producing fungi were isolated from peanut butter, taotjo, and shoyu. Direct extracts of 10% of the peanut butters tested and 5% of the kaomak tested contained large amounts of aflatoxins. The HPLC procedures used in this experiment utilized chloroform-ethyl acetate (3:1).

The ingestion of particles by macrophages leads to the prompt induction of prostaglandin (PG) synthesis. We have now dissected the endocytic process and examined the requirements of prostaglandin E (PGE) synthesis for particle attachment, membrane interiorization, and phagosome-lysosome fusion. Macrophages that were loaded with the polyanion dextran sulfate and exhibited a greater than 99% inhibition of phagosome-lysosome fusion produced normal amounts of PGE upon challenge with zymosan. Inhibition of membrane interiorization with cytochalasin D was similarly ineffective in blocking PGE synthesis. The addition of large numbers of unmodified polystyrene latex beads, which were readily ingested by macrophages, failed to stimulate PGE synthesis. However, when macrophages were challenged with latex beads coated with immune complexes, an increased synthesis of PGE resulted. No response occurred if the complex was prepared with the F(ab')2 fragment of IgG. Similar results occurred when nonphagocytizable Sephadex beads coated with immune complexes were employed. We conclude that particle binding to the Fc receptor of the macrophage plasma membrane is a sufficient stimulus for PGE synthesis.

A common approach to the reconstruction of early hominid behavior is the comparative study of living species. Some practitioners of this approach have strongly emphasized the use of carnivores while others have argued for the exclusive use of nonhuman primates. This paper takes the position that the interrelationship of primate and carnivore studies with respect to the reconstruction of early hominid behavior offers four possibilities. One is that the primate evidence is more useful and another is that the carnivore evidence is more useful. A third possibility is that primate and carnivore studies may supplement each other, i.e., taken separately, each body of evidence points toward the same conclusion. The fourth and most interesting posibility is that primate and carnivore studies may complement each other, i.e., taken together, they illuminate different aspects of a single hominid behavior pattern. It is argued that all four of these possibilities are applicable to the reconstruction of early hominid behavior, depending on the particular behavior pattern or research problem under consideration. This contention is supported with a series of examples. It is concluded that arguments favoring primates or carnivores should give way to discussions of how best to coordinate the data from these two valuable sources of inference about early hominid behavior.

The present study was undertaken to gain further insight into the roles of physical form and fiber in determining postprandial glucose and insulin responses to orally ingested, cooked starch. The starch was consumed as rice, either white (polished, ground, or unground) or brown (unpolished, ground, or unground). Each carbohydrate load was calculated to contain the equivalent of 75 g glucose. Both ground rice meals elicited much higher peak responses of glucose and insulin than either of the unground samples. This seemed to be due to the more rapid absorption of the ground rice since the area under the glucose curve during the first 60 min was higher for ground rice than for unground rice, irrespective of whether or not it was polished. However, the full 240 min glucose areas were similar for all four forms of rice suggesting that the early differences were due to different rates of absorption. The presence of fiber had little discernible effect on the overall glucose and insulin responses, since brown rice did not elicit a significantly lower glucose or insulin response than white rice. However, there was a sustained and significant increase in insulin secretion in response to ground compared with unground rice. It was concluded that the physical form of the rice was of particular importance in determining the postprandial glucose and insulin responses to rice and that fiber, per se, played a relatively minor role in this instance. Any factor (low surface area/starch ratio in this case) that limits access of the intestinal hydrolytic enzymes to the ingested starch would be expected to slow the rate of glucose absorption and thereby reduce the insulin secretion.

Fibre, more than any other dietary component, affects human large bowel function, causing an increase in stool output, dilution of colonic contents, a faster rate of passage through the gut and changes in the colonic metabolism of minerals, nitrogen and bile acids. (Fibre here refers to 'dietary fibre', which comprises plant cell wall polysaccharides and lignin, and not to 'crude fibre'.) It is thought that these changes are brought about by fibre passing through the gut undigested and holding water within its cellular structure. Although the amount of water taken up in vitro varies for different types of fibre, this does not correlate in the expected way with the effects these materials have on colonic function. This is because fibre is extensively degraded in the gut, probably by the colonic microflora. Using a newly developed method modified from ruminant nutrition for isolating bacteria, we have shown that the main component of human faeces is bacteria. We have shown that the main component of human faeces is bacteria. We show here that the way in which two contrasting types of dietary fibre act in the colon depends on the extent to which they are digested. Cabbage fibre, which is extensively broken down, provides a readily usable substrate for the stimulation of microbial growth, whereas wheat fibre remains largely undigested and retains water in the gut lumen.

In man, physiological amounts of vitamin B12 (cyanocobalamin) are absorbed by the intrinsic factor mediated mechanism exclusively in the ileum. Human faeces contain appreciable quantities of vitamin B12 or vitamin B12-like material presumably produced by bacteria in the colon, but this is unavailable to the non-coprophagic individual. However, the human small intestine also often harbours a considerable microflora and this is even more extensive in apparently healthy southern Indian subjects. We now show that at least two groups of organisms in the small bowel, Pseudomonas and Klebsiella sp., may synthesise significant amounts of the vitamin.

Post-exercise ketosis has been shown to occur in untrained subjects after 3--4 hours' walking, 1 1/2 hours' running or faster 20 minutes' cycling. Trained athletes appear to be resistant to post-exercise ketosis. The present study was undertaken to investigate whether post-exercise ketosis was related to the utilization of muscle glycogen during exercise. Fit and unfit subjects exercised on a bicycle ergometer for 15 minutes at their predicted maximal workload, or swam 90 m, with or without breath-holding, at 07h30. Blood lactate and ketone body levels were measured until 17h00. Although our subjects exercised more strenously than subjects in previous studies, neither the fit nor the unfit group developed ketone body levels which differed significantly from control day values after any of the three forms of exercise. Differences in food intake between fit and unfit, and between South African and Scottish subjects might explain these findings.

Male and female Long-Evans rats revealed decreased body weights and restricted growth rates when placed on a diet of Purina laboratory chow which was supplemented with 2.5 and 5.0% oxalic acid for a period of 70 days. Male and female rats ingesting 5.0% oxalic acid in the diet showed severe losses in body weight. Significant reduction in thyroid weight, 24-hr thyroid uptake of 125I, and plasma radioactivity were observed together with a significant increase in plasma thyroid-stimulating hormone in male and female rats ingesting dietary 5.0% oxalic acid. Chromatographic analysis of thyroid hydrolysates revealed an increase in thyroid labeling of monoiodotyrosine (MIT) which was associated with a decrease in labeling of diiodotyrosine (DIT) leading to elevation in MIT : DIT ratios. While the labeling of tetraiodothyronine (T4) was unaffected, a significant increase in triiodothyronine (T3) resulted in elevation of the T3 : T4 ratios. These results indicate that chronic ingestion of oxalic acid at the level of 5.0% can lead to a state of hypothyroidism.

Severe nutritional disorders, including kwashiorkor, marasmus, and rickets, were seen in four children and were due to parental food faddism, which should perhaps be regarded as a form of child abuse. All disorders were corrected with more normal diets and vitamin supplements. In view of the potentially serious consequences of restricted diets being fed to children, families at risk should be identified and acceptable nutritional advice given. When children are found to be suffering from undernutrition due to parental food faddism a court order will normally be a necessary step in providing adequate treatment and supervision.

The "Atkins dietary revolution" is a ketogenic diet consisting almost exclusively of food from animal origin. A similar diet was introduced as the "Banting diet" more than a century ago by the English physician Harvey. This carbohydrate-free diet is high in fat, cholesterol and purines. The measurable ketosis is a precondition for the effect of this kind of diet. However, the predictable hyperlipacidemia and ketosis are recognized health risks. Additionally, hypercholesterolemia is to be expected in a greater part of the adherents to such a diet. Even children under ketogenic diet develop hypercholesterolemia within a short time. A similar high-fat diet, known as the Sippy diet for ulcer therapy, was found earlier to cause an increased incidence in coronary heart disease. On the basis of the known facts the Atkins diet seems to be potentially hazardous to health, unless a controlled study is performed. However, considering the risks it seems very problematic to perform such a study.

We studied a six-month-old infant with severe megaloblastic anemia, coma and hyperpigmentation of the extremities. He was found to have methylmalonic aciduria (79 mumol per milligram of creatinine) and homocystinuria (0.85 mumol per milligram of creatinine). Additional biochemical abnormalities incl …

The resting metabolic rates (R.M.R.s) of 69 obese patients were measured during a period of weight stability. All except 4 women had a rate, in megajoules per 24 hours, in excess of that for subjects of normal weight. This increased R.M.R. is obscured by the traditional method of expressing R.M.R. per unit surface area. The high R.M.R. in the obese state was related not to the excess fat but to a 36% and 32% increase in the lean body mass of the men and women respectively. The R.M.R.s of 30 patients measured during weight-loss fell. The increase in R.M.R. in obesity is an important mechanism for achieving energy balance, whereas the progressive fall in R.M.R. during slimming demonstrates the need for a permanent reduction in food intake if energy balance is to be maintained on reaching normal weight. Measuring only the R.M.R. in the obese state is unlikely to help in understanding the pathogenesis of obesity.