Published Science

The effect of maternal diet on serum 1,25-dihydroxyvitamin D has not been determined in human lactation. Serum 1,25-dihydroxyvitamin D, other calcitropic hormones, osteocalcin, and minerals were examined in lactating and nonlactating women consuming a vegetarian or nonvegetarian diet. The vegetarian diet was a macrobiotic diet consisting primarily of whole cereal grains and vegetables; dairy products, eggs, and meats were generally avoided. We tested the thesis that the effect of lactation on serum 1,25-dihydroxyvitamin D is more pronounced in women on vegetarian diets than in those on nonvegetarian diets. Serum 1,25-dihydroxyvitamin D concentrations were significantly higher in lactating women compared with nonlactating women and in vegetarian compared with nonvegetarian women. Among vegetarian women, mean serum 1,25-dihydroxyvitamin D concentrations were 37% higher in the lactating group. For all subjects, serum parathyroid hormone was elevated during lactation compared with nonlactation. Thus, a vegetarian diet appears to be associated with increased serum 1,25-dihydroxyvitamin D during lactation.

In order to investigate whether the urinary excretion of 1-methylhistidine (1MH) might serve as an objective indicator of meat ingestion and exogenous 3-methylhistidine (3MH) intake, healthy subjects were fed an ovolactovegetarian diet. At five-day intervals they were given meat of different origin and 24-hour urinary excretions of 1MH and 3MH were determined. After beef intake there was a marked increase of 3MH and 1MH excretion. The elimination curves were found to follow first-order kinetics and to indicate similar elimination rates. 1MH was present in ten different types of meat analyzed. A strong linear relationship was found between increase in 3MH and 1MH excretion and the amount of chicken, pork, or plaice ingested. IMH may serve as an objective indicator of meat and exogenous 3MH intake, since it is present in meat, and, regardless of source, shows similar dose-independent kinetics, and has similar half-life to 3MH.

A 14-year-old white girl suffered from severe neurologic disturbances caused by vitamin B12 deficiency, due to failure to provide vitamin B12 supplementation to a strictly vegetarian diet. The disturbances resolved completely following treatment with vitamin B12. Physicians should be alert to the necessity for vitamin B12 supplementation for strict vegetarians, who eat no meat, fish, eggs, or dairy products.

The purpose of the study was to investigate the physiological assessment of a lacto-ovo-vegetarian diet, in comparison to a usual mixed diet and to analyse the effect of a lacto-ovo-vegetarian diet on nutritional status and blood parameters. Following an initial study, 34 resp. 33 subjects, three of them male took part in two investigation periods each lasting three weeks. During the first period (N) the subjects ingested the normal mixed diet, while in the second period (L) they were fed a lacto-ovo-vegetarian diet. The female subjects were aged 52.6 +/- 14.3 years, the male subjects 47.7 +/- 12.7 years. In both periods food supply ensued from the central kitchen of a nunnery. While preparing the meals, the food intake and the amount of nutrients was assessed with precise weighing methods. Also, the individual food consumption of the total subjects was estimated using food records. The nutritional physiological evaluation was based on the daily consumption of energy and nutrients to assess the nutrient supply, by means of the recommended dietary allowances of the German Nutrition Society. At the beginning of period N and both at the beginning and the end of period L, blood tests of the following parameters were performed: serum glucose, uric acid, and potassium, total protein, total cholesterol, HDL-, LDL-, VLDL-cholesterol, triglycerides, serum ferritin, serum iron, iron binding capacity, hemoglobin, s-GOT, s-GPT, thiamine, riboflavine, ascorbic acid. Measurements of body weight and height, body composition, skinfold thickness, circumferences, body surface, relative weight, blood pressure and sitting pulse rate completed the investigations. Furthermore, meal frequency and the daily individual energy requirement of the subjects were assessed by means of a diary of energy expenditure. On average, the daily energy consumption of women was 2020 +/- 611.3 kcal in period N, and 1970 +/- 592.4 kcal in period L. Consequently, there was a covering of energy requirements of 103% in period N and 99% in period L. Sources of energy consisted of 14% protein, 36.4% fat and 49.6% carbohydrates in period L, 13.6% protein, 39.6% fat, 44.7% carbohydrates and 2.1% alcohol in period N.

We have previously shown that short-term feeding [20 to 25 day induction period (IP)] normal rats a sucrose-rich diet (SRD) results in an increase of plasma (P), liver (L), and heart (H) triacylglycerol (TG) levels, accompanied by a drop in plasma postheparin total (T-TGL) and hepatic (H-TGL) triglyceride lipases activities, IV glucose intolerance (low Kg) and hyperinsulin responses both in vivo and in vitro, suggesting that a state of insulin resistance had developed. Since normalization of P-TG ensued in the medium term [40 to 55 day adaptation period (AP)] we decided to carry out a longitudinal, long-term (90 to 120 day) follow-up study to observe the dynamic behavior of the above metabolic and hormonal parameters as compared to the appropriate time course control rats were fed the standard chow (STD).(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of the current study was to determine whether there were differences in the fatty acid composition of milk from vegetarian mothers compared to nonvegetarian mothers and whether fatty acid composition was related to length of time on a vegetarian diet. Median time on a vegetarian diet was 81 months (range 36-132 months). Milk fat and fatty acids produced de novo in the mammary gland did not differ between diet groups. Milk from vegetarian women (n = 12) contained higher percentages of the precursors of arachidonic acid compared to nonvegetarian women (n = 7). Although there was no difference between diet group in the amount of arachidonic acid present (percent of total), a lower percentage was observed in women the longer they were on a vegetarian diet (r = -0.724, p = 0.008), with a corresponding higher percentage of the sum of precursors of arachidonic acid (r = 0.563, p = 0.056). The percentage of docosahexenoic acid was similar in the milk of vegetarian women compared to nonvegetarian women. The length of time on a vegetarian diet had no effect on these two fatty acids. In summary, differences in fatty acid content were apparent between the two dietary groups and changes with time on a vegetarian diet suggest that not only does current maternal diet affect fatty acid milk composition, but long-term dietary habits may as well.

Voluntary intake of protein, fat and carbohydrate (CHO) was modified by feeding young rats either a control purified diet [% metabolizable energy (ME): protein 21, fat 7, CHO 72], a control diet plus sucrose solution (20%) to drink (final intakes 17, 6 and 77% ME as protein, fat and CHO, respectively) or a low protein diet substituted with either CHO (8, 7 and 85% ME as protein, fat and CHO, respectively) or fat (8, 20 and 72% ME as protein, fat and CHO, respectively). Total ME intakes corrected for body size were similar for all rats, but body weight, energy gain and net energetic efficiency were lower in both low protein-fed groups than in the control group. The acute thermogenic response (% rise in oxygen consumption) to a standard balanced-nutrient meal was higher (12%) in sucrose-supplemented and in low protein groups (15-16%) than in control rats (8%). Brown adipose tissue protein content and thermogenic capacity (assessed from purine nucleotide binding to isolated mitochondria) were greater than control values in sucrose-fed and protein-deficient animals, and the greatest levels of activity were seen in low protein-fed rats with a high fat intake. The results demonstrate that the changes in energy balance, thermogenesis and brown adipose tissue activity that result from protein deficiency cannot be ascribed to changes in the level of energy intake or to a specific increase in the amount or proportion of either CHO or fat. They suggest that the protein-to-energy ratio must be the primary influence on thermogenesis and brown fat activity in these animals.

It has been hypothesized that the vitamin B-6 status of vegetarians and nonvegetarians may differ in relation to bioavailability of vitamin B-6. Fasting blood samples and 24-h urine collections were obtained from 13 Seventh-day Adventist (SDA) vegetarian and 16 non-SDA nonvegetarian women aged 50-83 y. The two groups were further subdivided into vitamin users and nonusers. Dietary intake was estimated from a 3-d diet record. Plasma pyridoxal 5'-phosphate (PLP) was measured by an enzymatic method. Vitamin B-6 intakes were similar and provided 85% of the RDA for both groups. The vegetarians consumed significantly more crude fiber than the nonvegetarians. No significant differences were found between the two groups for plasma PLP, urinary 4-pyridoxic acid, and urinary vitamin B-6 among vitamin nonusers or for age categories within groups. There appeared to be no adverse effect of fiber on the availability or metabolism of vitamin B-6 between these free-living groups.

The most consistent benefit of consumption of adequate dietary fiber is regular laxation; this effect alone justifies inclusion of fiber in the diet, in view of the enormous expenditure on drugs for digestive diseases. Dietary fiber has proved effective in decreasing symptoms of diverticular disease, Crohn's disease, and hemorrhoids in a limited number of small clinical studies. Fiber may also reduce the incidence of gallstone formation. Fiber is currently being touted as protection against colon cancer. However, the epidemiological and experimental data do not provide convincing evidence that fiber alone is a major determinant of risk for colon cancer. Furthermore, the data from international comparisons indicating that fiber is protective against colon cancer can be used in a similar simplistic manner to suggest that fiber may be a risk factor for stomach cancer. This should not dissuade individuals from obtaining adequate fiber from a wide variety of foods but should caution them against consumption of excessive amounts of fiber from a single source or from dietary supplements.

It is proposed that abnormalities of glucose and insulin metabolism have a role in both the aetiology and the clinical course of hypertension. There is resistance to insulin-stimulated glucose uptake in patients with hypertension, which is associated with glucose intolerance and hyperinsulinaemia. Hyperinsulinaemia could contribute to hypertension by stimulating the activity of the sympathetic nervous system and kidney sodium and volume reabsorption. Glucose intolerance and hyperinsulinaemia have been identified as risk factors for coronary artery disease, and their presence may help explain why the frequency of this disease has not been reduced by treatment of hypertension. The fact that several antihypertensive drugs deleteriously affect glucose, insulin, and lipid metabolism makes it even more important to consider these factors in the treatment of high blood pressure. © 1987.

An attempt has been made to reverse cachexia and to selectively deprive the tumour of metabolic substrates for energy production by feeding a ketogenic regime, since ketone bodies are considered important in maintaining homeostasis during starvation. As a model we have used a transplantable mouse adenocarcinoma of the colon (MAC 16) which produces extensive weight loss without a reduction in food intake. When mice bearing the MAC16 tumour were fed on diets in which up to 80% of the energy was supplied as medium chain triglycerides (MCT) with or without arginine 3-hydroxybutyrate host weight loss was reduced in proportion to the fat content of the diet, and there was also a reduction in the percentage contribution of the tumour to the final body weight. The increase in carcass weight in tumour-bearing mice fed high levels of MCT was attributable to an increase in both the fat and the non-fat carcass mass. Blood levels of free fatty acids (FFA) were significantly reduced by MCT addition. The levels of both acetoacetate and 3-hydroxybutyrate were elevated in mice fed the high fat diets, and tumour-bearing mice fed the normal diet did not show increased plasma levels of ketone bodies over the non-tumour-bearing group despite the loss of carcass lipids. Both blood glucose and plasma insulin levels were reduced in mice bearing the MAC16 tumour and this was not significantly altered by feeding the high fat diets. The elevation in ketone bodies may account for the retention of both the fat and the non-fat carcass mass. This is the first example of an attempt to reverse cachexia by a diet based on metabolic differences between tumour and host tissues, which aims to selectively feed the host at the expense of the tumour.

An attempt has been made to reverse cachexia and to selectively deprive the tumour of metabolic substrates for energy production by feeding a ketogenic regime, since ketone bodies are considered important in maintaining homeostasis during starvation. As a model we have used a transplantable mouse adenocarcinoma of the colon (MAC 16) which produces extensive weight loss without a reduction in food intake. When mice bearing the MAC16 tumour were fed on diets in which up to 80% of the energy was supplied as medium chain triglycerides (MCT) with or without arginine 3-hydroxybutyrate host weight loss was reduced in proportion to the fat content of the diet, and there was also a reduction in the percentage contribution of the tumour to the final body weight. The increase in carcass weight in tumour-bearing mice fed high levels of MCT was attributable to an increase in both the fat and the non-fat carcass mass. Blood levels of free fatty acids (FFA) were significantly reduced by MCT addition. The levels of both acetoacetate and 3-hydroxybutyrate were elevated in mice fed the high fat diets, and tumour-bearing mice fed the normal diet did not show increased plasma levels of ketone bodies over the non-tumour-bearing group despite the loss of carcass lipids. Both blood glucose and plasma insulin levels were reduced in mice bearing the MAC16 tumour and this was not significantly altered by feeding the high fat diets. The elevation in ketone bodies may account for the retention of both the fat and the non-fat carcass mass. This is the first example of an attempt to reverse cachexia by a diet based on metabolic differences between tumour and host tissues, which aims to selectively feed the host at the expense of the tumour.

The ECG QTc interval was significantly prolonged by pimozide but not haloperidol or placebo in a randomized clinical trial with 40 patients with Tourette's disorder. However, no adverse cardiac effects or differences in rate, rhythm, or waveform were found.

Fermentation in the Human Large Intestine and the Available Substrates

Calcium oxalate crystals are not encountered in normal animal tissues, except for the human thyroid, where they were found in 79 of 100 routine consecutive autopsies. They appear during childhood, and numbers of crystals increase with age. In diffuse hyperplasia, prevalence was higher, but crystals were fewer than expected. In adenomas and carcinomas, crystals were decreased except for three cases with a striking focal increase. None was found in 22 adult primate thyroids. After Clorox digestion of human thyroids, calcium oxalate dihydrate was identified by x-ray diffraction and infrared spectroscopy. Origin, tissue and species localization are discussed in relation to ascorbate metabolism, thyroperoxidase, and calcitonin. Possible metabolic roles are suggested. Calcium oxalate crystals injected in animals and humans initiate a foreign body reaction with giant cells. In Hashimoto's thyroiditis, crystals disappear but occasionally remain with giant cell reaction. In subacute thyroiditis, granulomas are related more to colloid than to crystals.

The effects of variations in dietary carbohydrate and fat intake on various aspects of carbohydrate and lipid metabolism were studied in patients with non-insulin-dependent diabetes mellitus (NIDDM). Two test diets were utilized, and they were consumed in random order over two 15-day periods. One diet was low in fat and high in carbohydrate, and corresponded closely to recent recommendations made by the American Diabetes Association (ADA), containing (as percent of total calories) 20 percent protein, 20 percent fat, and 60 percent carbohydrate, with 10 percent of total calories as sucrose. The other diet contained 20 percent protein, 40 percent fat, and 40 percent carbohydrate, with sucrose accounting for 3 percent of total calories. Although plasma fasting glucose and insulin concentrations were similar with both diets, incremental glucose and insulin responses from 8 a.m. to 4 p.m. were higher (p less than 0.01), and mean (+/- SEM) 24-hour urine glucose excretion was significantly greater (55 +/- 16 versus 26 +/- 4 g/24 hours p less than 0.02) in response to the low-fat, high-carbohydrate diet. In addition, fasting and postprandial triglyceride levels were increased (p less than 0.001 and p less than 0.05, respectively) and high-density lipoprotein (HDL) cholesterol concentrations were reduced (p less than 0.02) when patients with NIDDM ate the low-fat, high-carbohydrate diet. Finally, since low-density lipoprotein (LDL) concentrations did not change with diet, the HDL/LDL cholesterol ratio fell in response to the low-fat, high-carbohydrate diet. These results document that low-fat, high-carbohydrate diets, containing moderate amounts of sucrose, similar in composition to the recommendations of the ADA, have deleterious metabolic effects when consumed by patients with NIDDM for 15 days. Until it can be shown that these untoward effects are evanescent, and that long-term ingestion of similar diets will result in beneficial metabolic changes, it seems prudent to avoid the use of low-fat, high-carbohydrate diets containing moderate amounts of sucrose in patients with NIDDM.

Accounts of San (Bushman) shamanistic rock art have concentrated on the role of the trance dance in the generation of the paintings. This paper considers the role of dreaming to achieve ends similar to those served by the dance. Animal behaviour was depicted to suggest trance-dreaming, as it was to suggest other shamanistic experiences. Sleeping eland probably represent San shamans in trance-dreaming.

Study of dietary modification among 42 students from the People's Republic of China studying or teaching at Indiana University

[The authors found five categories of concern within the food guides: nutrition, economics, habits and tastes, supply, and education.]

A comprehensive review on the presence of certain important anti-nutritional and toxic factors in food legumes has been conducted. These substances include proteolytic inhibitors, phytohemagglutinins, lathyrogens, cyanogenetic compounds, compounds causing favism, factors affecting digestibility and saponins. These factors are shown to be widely present in leguminous foods which are important constituents of the diet of a large section of the world's population, and particularly, of people in the developing countries.

To study the relationship between the primary structure of the c-myc protein and some of its functional properties, we made in-frame insertion and deletion mutants of the normal human c-myc coding domain that was expressed from a retroviral promoter-enhancer. We assessed the effects of these mutations on the ability of c-myc protein to cotransform normal rat embryo cells with a mutant ras gene, iduce foci in a Rat-1-derived cell line (Rat-1a), and localize in nuclei. Using the cotransformation assay, we found two regions of the protein (amino acids 105 to 143 and 321 to 439) where integrity was critical: one region (amino acids 1 to 104) that tolerated insertion and small deletion mutations, but not large deletions, and another region (amino acids 144 to 320) that was largely dispensable. Comparison with regions that were important for transformation of Rat-1a cells revealed that some are essential for both activities, but others are important for only one or the other, suggesting that the two assays require different properties of the c-myc protein. Deletion of each of three regions of the c-myc protein (amino acids 106 to 143, 320 to 368, and 370 to 412) resulted in partial cytoplasmic localization, as determined by immunofluorescence or immunoprecipitation following subcellular fractionation. Some abnormally located proteins retained transforming activity; most proteins lacking transforming activity appeared to be normally located.

The circulating insulin and glucose responses in type II diabetic subjects were determined for 5 h after ingestion of various meals, each containing 50 g carbohydrate. The purpose of the study was to 1) systematically study the insulin response to several different high-starch foods, 2) determine whether this insulin response could be predicted by the glucose response, and 3) determine whether the glucose response could be predicted by the physical structure and digestibility of the ingested carbohydrate. Each subject served as his own control. Carbohydrate was given in the form of potatoes, bread, oatmeal, rice, lentils, kidney beans, cornflakes, high-amylose corn muffins, and low-amylose corn muffins. Bread, oatmeal, rice, lentils, kidney beans, and high-amylose corn muffins resulted in a significantly lower glucose area than 50 g glucose, and the glucose response generally could be predicted by the physical structure and the known digestibility of the ingested carbohydrate. The insulin rise was statistically significantly greater than would be predicted from the glucose response for oatmeal, lentils, kidney beans, and high-amylose corn muffins. Although not statistically significant, the mean was greater than predicted for every other food except potatoes when the insulin response to 50 g glucose was used as a standard. These results indicate that the insulin response cannot be predicted by the glucose response.

In spite of considerable work by many evolutionary biologists, it has not been possible to separate convincingly the human (H) - chimpanzee (C) - gorilla (G) trichotomy into a pair of sequential dichotomies. There are three possible phylogenetic groupings [(HC)G, (HG)C, and (CG)H], and each has its proponents. The evidence remains ambiguous, and instead of choosing among the available phylogenies, it might be better to provide a statement of their relative probabilities. We develop a likelihood analysis of mtDNA restriction-pattern data that can be used to make such probability statements and illustrate it with data on humans, chimpanzees, gorillas, orangutans, and gibbons. The results of our analyses suggest that the best fitting model is that of the (CG)H grouping, but with a very short time span between the first and second splits. For either the (HC)G or (HG)C hypothesis, a true trichotomy is the best model (no elapsed time between the two splits). Chi-square tests indicate no compelling resolution among the three models, however, and all three retain nontrivial posterior probabilities. We also compare each model with an alternative allowing for rate heterogeneity among lineages, but there is no convincing evidence for such heterogeneity. Our results suggest that, while it may eventually be possible to resolve the trichotomy into a pair of unambiguously ordered (but very close) dichotomies, it is possible that the ancestors of all three taxa (H, C, and G) were still conspecific subsequent to the second split, perhaps no more different than the “major races” of extant Homo sapiens.

We have isolated a 12 kb clone from the murine genome which we show by DNA transfection studies to contain an entire functional L-myc gene and the transcriptional promoter sequences necessary for its expression. We have also isolated a 3.1 kb cDNA sequence from a murine brain cDNA library which corresponds to most of the L-myc mRNA. We have identified the L-myc coding region within the genomic clone by a combination of S1 nuclease analyses. Northern blotting analyses and comparative nucleotide sequence analyses with the cDNA clone. The L-myc gene appears to be organized similarly to the other well-characterized myc-family genes, c-myc and N-myc. The predicted amino acid coding sequence of the L-myc gene indicates that the L-myc protein is significantly smaller than c- and N-myc, but is highly related. In particular, comparison of the N- and c-myc protein sequences reveals seven relatively conserved regions interspersed among non-conserved regions; the L-myc gene retains five of these conserved regions but lacks two others. In addition, a portion of one highly conserved region is encoded within a different region of the L-myc gene but, due to changes in the size of L-myc exons relative to those of N- and c-myc, maintains its overall position in the peptide backbone with respect to other conserved regions. We discuss these findings in the context of potential functional domains and the possibility of overlapping and distinct activities of myc-family proteins.

It has been generally assumed until recently that tropical rain forests are food rich biomes for human foragers, and that prehistoric hunter gatherers once lived completely independent of cultivated foods in such environments. An alternative hypothesis that such forests are actually food poor for humans is proposed here. Specifically, that wild starch foods such as yams were so scarce and so hard to extract that human foragers could not have lived in such biomes without recourse to cultivated foods. The symbiotic relationship found today between tropical rain forest hunter gatherers and farmers is not a recent phenomenon, but evolved long ago as an adaptative strategy for successfully expoliting the tropical forest.

There is now convincing evidence from epidemiological studies and randomized controlled trials that adoption of an ovo-lacto vegetarian diet leads to blood pressure reduction in both normotensive and hypertensive subjects. This effect appears to be independent of both dietary sodium and weight loss but additive to effects of weight reduction. Long-term adherence to a vegetarian diet is associated with less of a rise of blood pressure with age and a decreased prevalence of hypertension. The nutrients responsible for these effects have not been clearly identified and the mechanisms involved are unknown. Resolution of these questions is needed to enable more widespread adoption of dietary changes which may reduce the prevalence of hypertension, reduce antihypertensive drug dependence and by effects on blood pressure and blood lipids ameliorate the natural history of hypertensive cardiovascular disease.

Eighteen healthy, normal-weight women aged 19 to 27 years who had regular ovulatory menstrual cycles volunteered for the study. Blood was drawn on Mondays, Wednesdays, and Fridays throughout the control cycle and during a 6-week diet period that began with commencement of a new cycle. Nine women followed a vegetarian diet and nine a nonvegetarian diet. Both groups lost an average of 1 kg body weight/week. Seven of nine women in the vegetarian group became anovulatory. During the vegetarian diet the average luteinizing hormone (LH) values were significantly decreased during the midcycle and the luteal phase. Estradiol (E2) and progesterone (P) values were significantly lower during the luteal phase. In contrast, the nonvegetarian group did not show significant reduction of LH, E2, and P values during any part of the menstrual cycle. Seven of nine women in the nonvegetarian diet group maintained ovulatory cycles with no changes in cycle length or in the length of the follicular phase. In one woman who became anovulatory, E2 values did not increase during the follicular phase.

To study the effects of a low carbohydrate, isoenergetic diet on pulmonary physiology and sleep behavior, we measured pulmonary functions and respiratory gas exchange and carried out ambulatory electroencephalographic studies after a week's intake of isoenergetic diet containing only 50 g carbohydrate per day in 6 healthy female adult humans in a free-living condition. Compared with their normal intake, during the week of low carbohydrate intake there was a rise in the level of fasting plasma 3-hydroxybutyrate from 0.12 +/- 0.07 (mean +/- SD) to 1.01 +/- 0.40 mmol/L(P less than 0.01, paired t-test); a fall in serum bicarbonate from 26.2 +/- 0.75 to 25.0 +/- 1.41 mmol/L (P less than 0.05) and in serum chloride from 107 +/- 1.3 to 105 +/- 1.8 mmol/L (P less than 0.05). Serum urea rose from 4.3 +/- 0.71 to 5.7 +/- 0.70 mmol/L (P less than 0.01), and serum uric acid from 0.34 +/- 0.08 to 0.39 +/- 0.10 mmol/L (P less than 0.05). Functional residual capacity was increased from 2.07 +/- 0.35 to 2.26 +/- 0.34 L (P less than 0.01). Respiratory gas exchange ratio fell from 0.81 +/- 0.05 to 0.75 +/- 0.04 (P less than 0.05) and partial pressure of expired carbon dioxide reduced from 22 +/- 3.3 to 21 +/- 3.1 mmHg (P less than 0.05). There was a reduction in endogenous carbon dioxide production and arterial carbon dioxide tension. An analysis of ambulatory electroencephalogram showed that REM latency increased from 66 +/- 8 to 111 +/- 38 min (P less than 0.05), with no significant changes in sleep time and stages. These studies show that a low carbohydrate isoenergetic diet is tolerable, influences sleep behavior, reduces carbon dioxide production and respiratory gas exchange ratio, and may be therapeutically useful in patients with hypercapnic respiratory failure.

Megaloblastic anaemia in infancy is uncommon in western countries. We describe a case of an exclusively breast-fed monozygous twin with severe vitamin B12 deficiency with haematologic and neurologic abnormalities. Treatment with vitamin B12 resulted in a rapid haematological and clinical improvement.

Iron status of East Indian predominantly lacto-ovo vegetarian immigrants (59 males, mean age 37.7 +/- 10.5 yr; 55 females, mean age 33.3 +/- 7.4 yr) was assessed using dietary and biochemical-iron indices, including a Tri-index (TI) model. Iron deficiency was higher among females than males: 33% vs 5%, respectively, via the TI model (serum ferritin, serum-transferrin saturation, and mean corpuscular-hemoglobin concentration) and 18-42% vs 2-22%, respectively, via individual biochemical-iron indices. Rates of anemia calculated via the TI model in combination with low hemoglobin and mixed-distribution analysis (MDA) were similar and higher for the females (TI + Hb = 16%; MDA = 12%) than for the males (TI + Hb = 5%; MDA = 3%). High prevalence among females was attributed to low available iron intakes, concomitant with high intakes of dietary fiber, phytate, and tannins. We recommend the TI-model approach to estimate relative prevalence of iron deficiency in small surveys.

A group of young patients having multiple sclerosis was treated with dietary supplements containing calcium, magnesium and vitamin D for a period of one to two years. The experimental design employed self-pairing: the response of each patient was compared with his/her own case history as control. The number of exacerbations observed during the program was less than one half the number expected from case histories. No side effects were apparent. The dietary regimen may offer a new means of controlling the exacerbation rate in MS, at least for younger patients. The results tend to support a theory of MS which states that calcium and magnesium are important in the development, structure and stability of myelin.

The purpose of this study was to determine whether the postponement of fatigue in subjects fed carbohydrate during prolonged strenuous exercise is associated with a slowing of muscle glycogen depletion. Seven endurance-trained cyclists exercised at 71 +/- 1% of maximal O2 consumption (VO2max), to fatigue, while ingesting a flavored water solution (i.e., placebo) during one trial and while ingesting a glucose polymer solution (i.e., 2.0 g/kg at 20 min and 0.4 g/kg every 20 min thereafter) during another trial. Fatigue during the placebo trial occurred after 3.02 +/- 0.19 h of exercise and was preceded by a decline (P less than 0.01) in plasma glucose to 2.5 +/- 0.5 mM and by a decline in the respiratory exchange ratio (i.e., R; from 0.85 to 0.80; P less than 0.05). Glycogen within the vastus lateralis muscle declined at an average rate of 51.5 +/- 5.4 mmol glucosyl units (GU) X kg-1 X h-1 during the first 2 h of exercise and at a slower rate (P less than 0.01) of 23.0 +/- 14.3 mmol GU X kg-1 X h-1 during the third and final hour. When fed carbohydrate, which maintained plasma glucose concentration (4.2-5.2 mM), the subjects exercised for an additional hour before fatiguing (4.02 +/- 0.33 h; P less than 0.01) and maintained their initial R (i.e., 0.86) and rate of carbohydrate oxidation throughout exercise. The pattern of muscle glycogen utilization, however, was not different during the first 3 h of exercise with the placebo or the carbohydrate feedings. The additional hour of exercise performed when fed carbohydrate was accomplished with little reliance on muscle glycogen (i.e., 5 mmol GU X kg-1 X h-1; NS) and without compromising carbohydrate oxidation. We conclude that when they are fed carbohydrate, highly trained endurance athletes are capable of oxidizing carbohydrate at relatively high rates from sources other than muscle glycogen during the latter stages of prolonged strenuous exercise and that this postpones fatigue.

Vegetarians have an apparent diminished risk for the development of ischemic coronary heart disease. This may be secondary to dietary effects of plasma lipids and lipoproteins, but platelets, which may also play a role, have also been observed to have aberrant functions in vegetarians. We measured plasma lipid and lipoprotein levels, platelet function, platelet fatty acid levels, and platelet active prostaglandins in ten strict vegetarians (vegans), 15 lactovegetarians, and 25 age- and sex-matched omnivorous controls. The most striking observations were a highly significant rise in platelet linoleic acid concentration and a decline in platelet arachidonic acid concentration in both vegetarian subgroups as compared with omnivorous controls. Serum thromboxane and prostacyclin levels as well as results of platelet aggregation studies did not differ among the groups tested. Cholesterol levels were significantly lower in both vegetarian groups as compared with controls, but plasma high- and low-density lipoprotein levels were lower only in the vegan subgroup as compared with omnivores. If diet produces these changes in platelet fatty acid and plasma lipid levels it may contribute to the decreased risk of coronary heart disease and possibly atherosclerosis in vegetarians.

Cross-sectional epidemiological studies suggest that ovolactovegetarians have lower blood pressure and less of a rise in blood pressure with age than meat eaters. Controlled dietary intervention trials in normotensive and untreated mild hypertensive have provided more direct evidence for a direct dietary effect on blood pressure. Studies designed to identify the nutrients involved suggest that neither polyunsaturated fat, saturated fat, cholesterol, potassium, magnesium, sodium, or total protein intake are independently responsible. The pathophysiological mechanisms involved are also unclear. In view of the complex changes involved in changing to a vegetarian diet, research in this area needs to pay careful attention to experimental design. This is an area of research that has important implications for the control of hypertensive cardiovascular disease in the community by means other than drugs.

Fifty-nine healthy omnivores volunteered for a randomized crossover trial with a lacto-ovo-vegetarian (L-O-V) diet. Twenty-one 1-day diet records were kept throughout the project as a means of assessing food and nutrient intakes, and samples of serum and urine were assayed to evaluate change in prostanoid metabolism. While on the L-O-V diet subjects ate more vegetable protein, wholegrain cereals, polyunsaturated oils, fruits and vegetables, and avoided eating meat, fish or poultry. The L-O-V diet contained significantly more polyunsaturated fatty acids, fibre, vitamin C, vitamin E, magnesium, calcium and potassium, and less total protein, saturated fat, monounsaturated fat and vitamin B12 than the control omnivore diet. Changes in nutrient intakes were subjected to principal components analysis to identify dimensions of change in nutrient intakes. Three Factors accounted for 83% of the total variation in dietary intake. Blood pressure changes were significantly and negatively (F = 17.4, P less than 0.001 for systolic; F = 6.09, P = 0.02 for diastolic pressure) related to individual scores for only one Factor--that representing an increase in intake of polyunsaturated fat, fibre, vitamin C, vitamin E, calcium and magnesium, and a fall in intake of protein and vitamin B12. Blood pressure changes were unrelated to change in body weight or sodium intake. Serum and urinary prostanoids were not affected by eating the L-O-V diet.