Protein dietary reference intakes may be inadequate for vegetarians if low amounts of animal protein are consumed.

OBJECTIVE: The health benefits of vegetarian diets are well-recognized; however, long-term adherence to these diets may be associated with nutrient inadequacies, particularly vitamins B12 and D, calcium, iron, zinc, and protein. The dietary reference intakes (DRIs) expert panels recommended adjustments to the iron, zinc, and calcium DRIs for vegetarians to account for decreased bioavailability, but no adjustments were considered necessary for the protein DRI under the assumption that vegetarians consume about 50% of protein from animal (dairy/egg) sources. This study examined dietary protein sources in a convenience sample of 21 young adult vegetarian women who completed food logs on 4 consecutive days (3 weekdays and 1 weekend day). METHODS: The daily contribution percentages of protein consumed from cereals, legumes, nuts/seeds, fruits/vegetables, and dairy/egg were computed, and the protein digestibility corrected amino acid score of the daily diets was calculated. RESULTS: The calculated total dietary protein digestibility score for participants was 82 ± 1%, which differed significantly (P < 0.001) from the DRI reference score, 88%, and the 4-d average protein digestibility corrected amino acid score for the sample was 80 ± 2%, which also differed significantly (P < 0.001) from the DRI reference value, 100%. The analyses indicated that animal protein accounted for only 21% of dietary protein. CONCLUSION: This research suggests that the protein DRI for vegetarians consuming less than the expected amounts of animal protein (45% to 50% of total protein) may need to be adjusted from 0.8 to about 1.0 g/kg to account for decreased protein bioavailability. Copyright © 2011 Elsevier Inc. All rights reserved.

Effect of the vegetarian diet on non-communicable diseases.

A vegetarian diet generally includes plenty of vegetables and fruits, which are rich in phytochemicals, antioxidants, fiber, magnesium, vitamins C and E, Fe³⁺, folic acid and n-6 polyunsaturated fatty acid (PUFA), and is low in cholesterol, total fat and saturated fatty acid, sodium, Fe²⁺, zinc, vitamin A, B₁₂ and D, and especially n-3 PUFA. Mortality from all-cause, ischemic heart disease, and circulatory and cerebrovascular diseases was significantly lower in vegetarians than in omnivorous populations. Compared with omnivores, the incidence of cancer and type 2 diabetes was also significantly lower in vegetarians. However, vegetarians have a number of increased risk factors for non-communicable diseases such as increased plasma homocysteine, mean platelet volume and platelet aggregability compared with omnivores, which are associated with low intake of vitamin B₁₂ and n-3 PUFA. Based on the present data, it would seem appropriate for vegetarians to carefully design their diet, specifically focusing on increasing their intake of vitamin B₁₂ and n-3 PUFA to further reduce already low mortality and morbidity from non-communicable diseases. © 2013 Society of Chemical Industry.

Estrogen excretion patterns and plasma levels in vegetarian and omnivorous women.

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.

Effect of diet on excretion of estrogens in pre- and postmenopausal women.

Fecal, urinary, and plasma estrogens and plasma androgens were studied in healthy pre- and postmenopausal vegetarian and omnivorous women. Dietary histories of the subjects revealed that omnivores consumed a higher percentage of total protein and fat from animal sources. The total 72-hr fecal excretion as measured by dry weight was higher for vegetarians. Preliminary results indicate that vegetarian women excrete 2 to 3 times more estrogens in feces than do omnivores and that omnivores have about 50% higher mean plasma level of unconjugated estrone and estradiol than vegetarians. Estriol-3-glucuronide, a compound that is formed upon reabsorption of free estriol from the intestine, is found in lower concentrations in the urine of vegetarians. These data suggest that in vegetarians a greater amount of the biliary estrogens escape reabsorption and are excreted with the feces. The differences in estrogen metabolism may explain the lower incidence of breast cancer in vegetarian women.

Vegetarian diets: what do we know of their effects on common chronic diseases?

A number of studies have evaluated the health of vegetarians. Others have studied the health effects of foods that are preferred or avoided by vegetarians. The purpose of this review is to look critically at the evidence on the health effects of vegetarian diets and to seek possible explanations where results appear to conflict. There is convincing evidence that vegetarians have lower rates of coronary heart disease, largely explained by low LDL cholesterol, probable lower rates of hypertension and diabetes mellitus, and lower prevalence of obesity. Overall, their cancer rates appear to be moderately lower than others living in the same communities, and life expectancy appears to be greater. However, results for specific cancers are much less convincing and require more study. There is evidence that risk of colorectal cancer is lower in vegetarians and in those who eat less meat; however, results from British vegetarians presently disagree, and this needs explanation. It is probable that using the label “vegetarian” as a dietary category is too broad and that our understanding will be served well by dividing vegetarians into more descriptive subtypes. Although vegetarian diets are healthful and are associated with lower risk of several chronic diseases, different types of vegetarians may not experience the same effects on health.

A vegetarian dietary pattern as a nutrient-dense approach to weight management: an analysis of the national health and nutrition examination survey...

BACKGROUND: Population-based studies have shown that vegetarians have lower body mass index than nonvegetarians, suggesting that vegetarian diet plans may be an approach for weight management. However, a perception exists that vegetarian diets are deficient in certain nutrients. OBJECTIVE: To compare dietary quality of vegetarians, nonvegetarians, and dieters, and to test the hypothesis that a vegetarian diet would not compromise nutrient intake when used to manage body weight. DESIGN: Cross-sectional analysis of National Health and Nutrition Examination Survey (1999-2004) dietary and anthropometric data. Diet quality was determined using United States Department of Agriculture's Healthy Eating Index 2005. Participants included adults aged 19 years and older, excluding pregnant and lactating women (N = 13,292). Lacto-ovo vegetarian diets were portrayed by intakes of participants who did not eat meat, poultry, or fish on the day of the survey (n = 851). Weight-loss diets were portrayed by intakes of participants who consumed 500 kcal less than their estimated energy requirements (n = 4,635). Mean nutrient intakes and body mass indexes were adjusted for energy, sex, and ethnicity. Using analysis of variance, all vegetarians were compared to all nonvegetarians, dieting vegetarians to dieting nonvegetarians, and nondieting vegetarians to nondieting nonvegetarians. RESULTS: Mean intakes of fiber, vitamins A, C, and E, thiamin, riboflavin, folate, calcium, magnesium, and iron were higher for all vegetarians than for all nonvegetarians. Although vegetarian intakes of vitamin E, vitamin A, and magnesium exceeded that of nonvegetarians (8.3 ± 0.3 vs 7.0 ± 0.1 mg; 718 ± 28 vs 603 ± 10 μg; 322 ± 5 vs 281 ± 2 mg), both groups had intakes that were less than desired. The Healthy Eating Index score did not differ for all vegetarians compared to all nonvegetarians (50.5 ± 0.88 vs 50.1 ± 0.33, P = 0.6). CONCLUSIONS: These findings suggest that vegetarian diets are nutrient dense, consistent with dietary guidelines, and could be recommended for weight management without compromising diet quality. Copyright © 2011 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

The low-methionine content of vegan diets may make methionine restriction feasible as a life extension strategy.

Recent studies confirm that dietary methionine restriction increases both mean and maximal lifespan in rats and mice, achieving "aging retardant" effects very similar to those of caloric restriction, including a suppression of mitochondrial superoxide generation. Although voluntary caloric restriction is never likely to gain much popularity as a pro-longevity strategy for humans, it may be more feasible to achieve moderate methionine restriction, in light of the fact that vegan diets tend to be relatively low in this amino acid. Plant proteins - especially those derived from legumes or nuts - tend to be lower in methionine than animal proteins. Furthermore, the total protein content of vegan diets, as a function of calorie content, tends to be lower than that of omnivore diets, and plant protein has somewhat lower bioavailability than animal protein. Whole-food vegan diets that moderate bean and soy intake, while including ample amounts of fruit and wine or beer, can be quite low in methionine, while supplying abundant nutrition for health (assuming concurrent B12 supplementation). Furthermore, low-fat vegan diets, coupled with exercise training, can be expected to promote longevity by decreasing systemic levels of insulin and free IGF-I; the latter effect would be amplified by methionine restriction - though it is not clear whether IGF-I down-regulation is the sole basis for the impact of low-methionine diets on longevity in rodents.

Oestrogen levels in serum and urine of premenopausal women eating low and high amounts of meat.

OBJECTIVE: Based on the hypothesis that high-meat diets may increase breast cancer risk through hormonal pathways, the present analysis compared oestrogens in serum and urine by meat-eating status. DESIGN: Intervention with repeated measures. SETTING: Two randomized soya trials (BEAN1 and BEAN2) among premenopausal healthy women. SUBJECTS: BEAN1 participants completed seven unannounced 24 h dietary recalls and donated five blood and urine samples over 2 years. BEAN2 women provided seven recalls and three samples over 13 months. Serum samples were analysed for oestrone (E₁) and oestradiol (E₂) using RIA. Nine oestrogen metabolites were measured in urine by LC-MS. Semi-vegetarians included women who reported consuming <30 g of red meat, poultry and fish daily, and pescatarians those who reported consuming <20 g of meat/poultry but >10 g of fish daily. All other women were classified as non-vegetarians. We applied mixed models to compute least-square means by vegetarian status adjusted for potential confounders. RESULTS: The mean age of the 272 participants was 41·9 (SD 4·5) years. Serum E₁ (85 v. 100 pg/ml, P = 0·04) and E₂ (140 v. 154 pg/ml, P = 0·04) levels were lower in the thirty-seven semi-vegetarians than in the 235 non-vegetarians. The sum of the nine urinary oestrogen metabolites (183 v. 200 pmol/mg creatinine, P = 0·27) and the proportions of individual oestrogens and pathways did not differ by meat-eating status. Restricting the models to the samples collected during the luteal phase strengthened the associations. CONCLUSIONS: Given the limitations of the study, the lower levels of serum oestrogens in semi-vegetarians than non-vegetarians need confirmation in larger populations.

Iodine Status and Thyroid Function of Boston-Area Vegetarians and Vegans

Context: Adequate dietary iodine is required for normal thyroid function. The iodine status and thyroid function of U.S. vegetarians and vegans have not been previously studied. Environmental perchlorate and thiocyanate (inhibitors of thyroid iodine uptake) exposures may adversely affect thyroid function. Objective: The objective of the study was to assess the iodine status and thyroid function of U.S. vegetarians (consume plant based products, eggs, milk; abstain from meat, poultry, fish, shellfish) and vegans (avoid all animal products) and whether these may be affected by environmental perchlorate and thiocyanate exposures. Design and Setting: This was a cross-sectional assessment of urinary iodine, perchlorate, and thiocyanate concentrations and serum thyroid function in Boston-area vegetarians and vegans. Subjects: One hundred forty-one subjects (78 vegetarians, 63 vegans) were recruited; one vegan was excluded. Results: Median urinary iodine concentration of vegans (78.5 μg/liter; range 6.8–964.7 μg/liter) was lower than vegetarians (147.0 μg/liter; range 9.3–778.6 μg/liter) (P < 0.01). Adjusted for cigarette smoking (confirmed by urinary cotinine levels) and thiocyanate-rich food consumption, median urinary thiocyanate concentration of vegans (630 μg/liter; range 108-3085 μg/liter) was higher than vegetarians (341 μg/liter; range 31–1963 μg/liter) (P < 0.01). There were no between-group differences in urinary perchlorate concentrations (P = 0.75), TSH (P = 0.46), and free T4 (P = 0.77). Urinary iodine, perchlorate, and thiocyanate levels were not associated with TSH (P = 0.59) or free T4 (P = 0.14), even when adjusted for multiple variables. Conclusions: U.S. vegetarians are iodine sufficient. U.S. vegans may be at risk for low iodine intake, and vegan women of child-bearing age should supplement with 150 μg iodine daily. Environmental perchlorate and thiocyanate exposures are not associated with thyroid dysfunction in these groups.

Vegetarian diets are associated with healthy mood states: a cross-sectional study in Seventh Day Adventist adults

Background The physical health status of vegetarians has been extensively reported, but there is limited research regarding the mental health status of vegetarians, particularly with regard to mood. Vegetarian diets exclude fish, the major dietary source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), critical regulators of brain cell structure and function. Omnivorous diets low in EPA and DHA are linked to impaired mood states in observational and experimental studies. Methods We examined associations between mood state and polyunsaturated fatty acid intake as a result of adherence to a vegetarian or omnivorous diet in a cross-sectional study of 138 healthy Seventh Day Adventist men and women residing in the Southwest. Participants completed a quantitative food frequency questionnaire, Depression Anxiety Stress Scale (DASS), and Profile of Mood States (POMS) questionnaires. Results Vegetarians (VEG:n = 60) reported significantly less negative emotion than omnivores (OMN:n = 78) as measured by both mean total DASS and POMS scores (8.32 ± 0.88 vs 17.51 ± 1.88, p = .000 and 0.10 ± 1.99 vs 15.33 ± 3.10, p = .007, respectively). VEG reported significantly lower mean intakes of EPA (p < .001), DHA (p < .001), as well as the omega-6 fatty acid, arachidonic acid (AA; p < .001), and reported higher mean intakes of shorter-chain α-linolenic acid (p < .001) and linoleic acid (p < .001) than OMN. Mean total DASS and POMS scores were positively related to mean intakes of EPA (p < 0.05), DHA (p < 0.05), and AA (p < 0.05), and inversely related to intakes of ALA (p < 0.05), and LA (p < 0.05), indicating that participants with low intakes of EPA, DHA, and AA and high intakes of ALA and LA had better mood. Conclusions The vegetarian diet profile does not appear to adversely affect mood despite low intake of long-chain omega-3 fatty acids.

The associations of diet with serum insulin-like growth factor I and its main binding proteins in 292 women meat-eaters, vegetarians, and vegans.

The lower rates of some cancers in Asian countries than in Western countries may be partly because of diet, although the mechanisms are unknown. The aim of this cross-sectional study was to determine whether a plant-based (vegan) diet is associated with a lower circulating level of insulin-like growth factor I (IGF-I) compared with a meat-eating or lacto-ovo-vegetarian diet among 292 British women, ages 20-70 years. The mean serum IGF-I concentration was 13% lower in 92 vegan women compared with 99 meat-eaters and 101 vegetarians (P = 0.0006). The mean concentrations of both serum IGF-binding protein (IGFBP)-1 and IGFBP-2 were 20-40% higher in vegan women compared with meat-eaters and vegetarians (P = 0.005 and P = 0.0008 for IGFBP-1 and IGFBP-2, respectively). There were no significant differences in IGFBP-3, C-peptide, or sex hormone-binding globulin concentrations between the diet groups. Intake of protein rich in essential amino acids was positively associated with serum IGF-I (Pearson partial correlation coefficient; r = 0.27; P < 0.0001) and explained most of the differences in IGF-I concentration between the diet groups. These data suggest that a plant-based diet is associated with lower circulating levels of total IGF-I and higher levels of IGFBP-1 and IGFBP-2.

Sympathetic nervous system activity and resting metabolic rate in vegetarians.

We examined the resting metabolic rate (RMR) and sympathetic nervous system activity of young male vegetarians (n = 17) and nonvegetarians (n = 40). Subjects were characterized for RMR by indirect calorimetry, norepinephrine kinetics from infusions of tritiated norepinephrine, energy and macronutrient intake from a 3-day food diary, and body composition by underwater weighing. Vegetarians reported a greater relative intake of carbohydrates (62% +/- 5% v 51% +/- 6%, P < .01) and a lower relative intake of fat (25% +/- 5% v 33% +/- 6%, P < .01) than nonvegetarians, whereas no differences were observed in daily energy intake, body composition, or maximal aerobic capacity (VO2max) between groups. Vegetarians exhibited an 11% higher absolute RMR (1.29 +/- 0.15 v 1.16 +/- 0.13 kcal/min, P < .01), a higher plasma concentration of norepinephrine (216 +/- 33 v 165 +/- 18 pg/mL, P < .01), and a greater norepinephrine appearance rate (0.50 +/- 0.08 v 0.36 +/- 0.09 micrograms/min, P < .01) than nonvegetarians. After statistically controlling for differences in relative amounts of carbohydrate and fat in the diet and for norepinephrine concentrations, no significant differences in adjusted RMR between vegetarians and nonvegetarians were noted. These results suggest that the higher RMR observed in young male vegetarians is partially mediated by differences in dietary macronutrient composition and increased sympathetic nervous system activity.

Vegetarian diet and cholesterol and triglycerides levels.

OBJECTIVE: Compare levels of triglyceride (TG), total cholesterol (TC), low density lipoprotein (LDL) and high density lipoprotein (HDL) among vegetarians and omnivores. METHODS: Blood samples were collected from 76 individuals--both males and females--separated in four different diet groups: omnivores, lacto-ovo vegetarians, lacto vegetarians, and restricted vegetarians (or vegans). Dosing was done for: TC, LDL, HDL and TG. RESULTS: Significant difference was reported for TC, LDL and TG levels among the samples. Higher levels were reported by omnivores, with decreased levels for vegetarians as animal products were restricted, with lowest levels having been reported by vegans. Mean and standard deviation for TC were 208.09 +/- 49.09 mg/dl in the group of omnivores, and 141.06 +/- 30.56 mg/dl in the group of vegans (p < 0.001). LDL values for omnivores and vegans were respectively: 123.43 +/- 42.67 mg/dl and 69.28 +/- 29.53 mg/dl (p < 0.001). As for TG, those values were 155.68 +/- 119.84 mg/dl and 81.67 +/- 81.90 mg/dl (p < 0.01). As for HDL level no difference was reported between the samples, but HDL/TC ratio was significantly higher in vegans (p = 0.01). CONCLUSION: Vegetarian diet was associated to lower levels of TG, TC and LDL as compared to the diet of omnivores.

Renal function parameters of Thai vegans compared with non-vegans.

In Asia, vegetarianism is a well-established eating behavior. It appears that the adoption of a vegan diet leads to a lessening of several health risk factors. Although vegetarianism has some notable effects on the hematological system, the effect on the nephrological system has not been well clarified. The pattern of renal function parameters was studied in 25 Thai vegans compared with 25 non-vegetarians. Of the studied parameters, it was found that urine protein was significantly different (p < 0.05) in vegans and controls. Vegans had significantly lower urine protein level.

Does a vegetarian diet reduce the occurrence of diabetes?

We propose the hypothesis that a vegetarian diet reduces the risk of developing diabetes. Findings that have generated this hypothesis are from a population of 25,698 adult White Seventh-day Adventists identified in 1960. During 21 years of follow-up, the risk of diabetes as an underlying cause of death in Adventists was approximately one-half the risk for all US Whites. Within the male Adventist population, vegetarians had a substantially lower risk than non-vegetarians of diabetes as an underlying or contributing cause of death. Within both the male and female Adventist populations, the prevalence of self-reported diabetes also was lower in vegetarians than in non-vegetarians. The associations observed between diabetes and meat consumption were apparently not due to confounding by over- or under-weight, other selected dietary factors, or physical activity. All of the associations between meat consumption and diabetes were stronger in males than in females.

Protein and coronary heart disease: the role of different protein sources.

Meat protein is associated with an increase in risk of heart disease. Recent data have shown that meat protein appeared to be associated with weight gain over 6.5 years, with 1 kg of weight increase per 125 g of meat per day. In the Nurses' Health Study, diets low in red meat, containing nuts, low-fat dairy, poultry, or fish, were associated with a 13% to 30% lower risk of CHD compared with diets high in meat. Low-carbohydrate diets high in animal protein were associated with a 23% higher total mortality rate whereas low-carbohydrate diets high in vegetable protein were associated with a 20% lower total mortality rate. Recent soy interventions have been assessed by the American Heart Association and found to be associated with only small reductions in LDL cholesterol. Although dairy intake has been associated with a lower weight and lower insulin resistance and metabolic syndrome, the only long-term (6 months) dairy intervention performed so far has shown no effects on these parameters.

Vegan proteins may reduce risk of cancer, obesity, and cardiovascular disease by promoting increased glucagon activity.

Amino acids modulate the secretion of both insulin and glucagon; the composition of dietary protein therefore has the potential to influence the balance of glucagon and insulin activity. Soy protein, as well as many other vegan proteins, are higher in non-essential amino acids than most animal-derived food proteins, and as a result should preferentially favor glucagon production. Acting on hepatocytes, glucagon promotes (and insulin inhibits) cAMP-dependent mechanisms that down-regulate lipogenic enzymes and cholesterol synthesis, while up-regulating hepatic LDL receptors and production of the IGF-I antagonist IGFBP-1. The insulin-sensitizing properties of many vegan diets--high in fiber, low in saturated fat--should amplify these effects by down-regulating insulin secretion. Additionally, the relatively low essential amino acid content of some vegan diets may decrease hepatic IGF-I synthesis. Thus, diets featuring vegan proteins can be expected to lower elevated serum lipid levels, promote weight loss, and decrease circulating IGF-I activity. The latter effect should impede cancer induction (as is seen in animal studies with soy protein), lessen neutrophil-mediated inflammatory damage, and slow growth and maturation in children. In fact, vegans tend to have low serum lipids, lean physiques, shorter stature, later puberty, and decreased risk for certain prominent 'Western' cancers; a vegan diet has documented clinical efficacy in rheumatoid arthritis. Low-fat vegan diets may be especially protective in regard to cancers linked to insulin resistance--namely, breast and colon cancer--as well as prostate cancer; conversely, the high IGF-I activity associated with heavy ingestion of animal products may be largely responsible for the epidemic of 'Western' cancers in wealthy societies. Increased phytochemical intake is also likely to contribute to the reduction of cancer risk in vegans. Regression of coronary stenoses has been documented during low-fat vegan diets coupled with exercise training; such regimens also tend to markedly improve diabetic control and lower elevated blood pressure. Risk of many other degenerative disorders may be decreased in vegans, although reduced growth factor activity may be responsible for an increased risk of hemorrhagic stroke. By altering the glucagon/insulin balance, it is conceivable that supplemental intakes of key non-essential amino acids could enable omnivores to enjoy some of the health advantages of a vegan diet. An unnecessarily high intake of essential amino acids--either in the absolute sense or relative to total dietary protein--may prove to be as grave a risk factor for 'Western' degenerative diseases as is excessive fat intake.

Vegetarianism and menstrual cycle disturbances: is there an association?

The question of whether menstrual disturbances are more common in vegetarian than in nonvegetarian women is complex. Disturbances of the cycle may be clinical (ie, amenorrhea or oligomenorrhea) or subclinical (i.e., normal-length cycles with anovulation or a short or defective luteal phase). Detection of the latter requires that the menstrual cycle be monitored, but may help prevent recruitment bias in studies comparing vegetarians with nonvegetarians because vegetarians with menstrual disturbances may be more likely to volunteer for a study on menstrual disturbances and vegetarianism. Three general mechanisms that could contribute to menstrual disturbances that may differ between vegetarians and nonvegetarians include energy imbalances associated with body-weight disturbances or exercise, psychosocial and cognitive factors, and dietary components. Evidence for each of these mechanisms is reviewed and studies comparing menstrual function between vegetarians and nonvegetarians are described in this article. Although results from several cross-sectional studies suggest that clinical menstrual disturbances may be more common in vegetarians, a prospective study that controlled for many potential confounders found that subclinical disturbances were less common in weight-stable, healthy vegetarian women. Because the sample studied may not be representative of all vegetarian women, however, these results cannot be generalized. Population studies are needed to draw definitive conclusions.

Taiwanese vegetarians have higher insulin sensitivity than omnivores.

The present study was designed to examine the effects of habitual consumption of Taiwanese vegetarian diets on hormonal secretion, and on lipid and glycaemic control. Of the ninety-eight healthy female adults recruited from Hualien, Taiwan (aged 31-45 years), forty-nine were Buddhist lactovegetarians and forty-nine were omnivores. Dietary intakes were measured, and blood levels of nutrients and hormones were analysed. Vegetarians consumed less energy, fat and protein, but more fibre than the omnivores. Compared with the omnivores, the vegetarians had, on average, lower BMI and smaller waist circumference. Except for slightly lower levels of thyroxine (T4) in vegetarians, vegetarians and omnivores both showed similar levels of triiodothyronine (T3), free T4, thyroid-stimulating hormone, T3:T4 ratio and cortisol. Compared with the omnivores, the vegetarians had significantly lower levels of fasting insulin (median: 35.3 v. 50.6 pmol/l) and plasma glucose (mean: 4.7 (se 0.05) v. 4.9 (se 0.05) mmol/l). Insulin resistance, as calculated by the homeostasis model assessment method, was significantly lower in the vegetarians than in the omnivores (median: 1.10 v. 1.56), while beta-cell function was not different between the two groups. BMI and diet were both independent predictors for insulin resistance, and contributed 18 and 15 % of the variation in insulin resistance, respectively. In conclusion, Taiwanese vegetarians had lower glucose and insulin levels and higher insulin sensitivity than did the omnivores. Diet and lower BMI were partially responsible for the high insulin sensitivity observed in young Taiwanese vegetarians.

Plasma total homocysteine status of vegetarians compared with omnivores: a systematic review and meta-analysis.

There is strong evidence indicating that elevated plasma total homocysteine (tHcy) levels are a major independent biomarker and/or a contributor to chronic conditions, such as CVD. A deficiency of vitamin B₁₂ can elevate homocysteine. Vegetarians are a group of the population who are potentially at greater risk of vitamin B₁₂ deficiency than omnivores. This is the first systematic review and meta-analysis to appraise a range of studies that compared the homocysteine and vitamin B₁₂ levels of vegetarians and omnivores. The search methods employed identified 443 entries, from which, by screening using set inclusion and exclusion criteria, six eligible cohort case studies and eleven cross-sectional studies from 1999 to 2010 were revealed, which compared concentrations of plasma tHcy and serum vitamin B₁₂ of omnivores, lactovegetarians or lacto-ovovegetarians and vegans. Of the identified seventeen studies (3230 participants), only two studies reported that vegan concentrations of plasma tHcy and serum vitamin B₁₂ did not differ from omnivores. The present study confirmed that an inverse relationship exists between plasma tHcy and serum vitamin B₁₂, from which it can be concluded that the usual dietary source of vitamin B₁₂ is animal products and those who choose to omit or restrict these products are destined to become vitamin B₁₂ deficient. At present, the available supplement, which is usually used for fortification of food, is the unreliable cyanocobalamin. A well-designed study is needed to investigate a reliable and suitable supplement to normalise the elevated plasma tHcy of a high majority of vegetarians. This would fill the gaps in the present nutritional scientific knowledge.

VEGETARIAN DIETS AND THE INCIDENCE OF CANCER IN A LOW-RISK POPULATION

Background Cancer is the second leading cause of death in the US. Dietary factors account for at least 30% of all cancers in Western countries. Since people do not consume individual foods but rather combinations of them, the assessment of dietary patterns may offer valuable information when determining associations between diet and cancer risk. Methods We examined the association between dietary patterns (non-vegetarians, lacto, pesco, vegan, and semi-vegetarian) and the overall cancer incidence among 69,120 participants of the Adventist Health Study-2. Cancer cases were identified by matching to cancer registries. Cox-proportional hazard regression analysis was performed to estimate hazard ratios, with “attained age” as the time variable. Results 2,939 incident cancer cases were identified. The multivariate HR of overall cancer risk among vegetarians compared to non-vegetarians was statistically significant (HR=0.92; 95%CI: 0.85, 0.99) for both genders combined. Also, a statistically significant association was found between vegetarian diet and cancers of the gastrointestinal tract (HR=0.76; 95%CI: 0.63, 0.90). When analyzing the association of specific vegetarian dietary patterns, vegan diets showed statistically significant protection for overall cancer incidence (HR=0.84; 95%CI: 0.72, 0.99) in both genders combined and for female-specific cancers (HR=0.66; 95%CI: 0.47, 0.92). Lacto-ovo-vegetarians appeared to be associated with decreased risk of cancers of the gastrointestinal system (HR=0.75; 95%CI: 0.60, 0.92). Conclusion Vegetarian diets seem to confer protection against cancer. Impact Vegan diet seems to confer lower risk for overall and female-specific cancer compared to other dietary patterns. The lacto-ovo-vegetarian diets seem to confer protection from cancers of the gastrointestinal tract.

Periodontal conditions in vegetarians: a clinical study.

BACKGROUND/OBJECTIVES: Investigations about possible correlations between vegetarian diet and periodontal conditions are rare and characterized by small case numbers. The aim of this clinical study was to investigate the influence of a vegetarian diet on periodontal parameters with an appropriate sample size. SUBJECTS/METHODS: A total of 200 patients, 100 vegetarians and 100 non-vegetarians, were included in the study. All patients were examined including a full mouth assessment of the periodontal and dental conditions. In addition, a questionnaire was handed out to ask for patients' oral hygiene habits and level of education. For statistical analysis the Mann-Whitney Test (χ(2) for analysis of the questionnaire) was applied (level of significance: P<0.05). RESULTS: Well known periodontal risk factors like age, gender and smoking habits were equally distributed within each group (71 females, 29 males, respectively and 10 smokers in each group; mean age: 41.45 years vegetarians versus 41.72 years non-vegetarians). Vegetarians had significantly lower probing pocket depths (P=0.039), bleeding on probing (P=0.001), periodontal screening index (P=0.012), a better hygiene index (P<0.001) and less mobile teeth (P=0.013). Dental examinations revealed significantly less missing teeth (P=0.018) but also more decayed (P=0.001) and eroded (P=0.026) teeth in vegetarians. Furthermore, vegetarians had a higher level of education (P<0.001), but visited dentists significantly less frequent. CONCLUSIONS: Vegetarians revealed better periodontal conditions (less inflammation signs, less periodontal damage and a better dental home care). However, it should be considered that vegetarians are not only avoiding meat in their nutrition but are also characterized by an overall healthier life style.

Vegetarian Dietary Patterns and Mortality in Adventist Health Study 2

Importance Some evidence suggests vegetarian dietary patterns may be associated with reduced mortality, but the relationship is not well established. Objective To evaluate the association between vegetarian dietary patterns and mortality. Design Prospective cohort study; mortality analysis by Cox proportional hazards regression, controlling for important demographic and lifestyle confounders. Setting Adventist Health Study 2 (AHS-2), a large North American cohort. Participants A total of 96 469 Seventh-day Adventist men and women recruited between 2002 and 2007, from which an analytic sample of 73 308 participants remained after exclusions. Exposures Diet was assessed at baseline by a quantitative food frequency questionnaire and categorized into 5 dietary patterns: nonvegetarian, semi-vegetarian, pesco-vegetarian, lacto-ovo–vegetarian, and vegan. Main Outcome and Measure The relationship between vegetarian dietary patterns and all-cause and cause-specific mortality; deaths through 2009 were identified from the National Death Index. Results There were 2570 deaths among 73 308 participants during a mean follow-up time of 5.79 years. The mortality rate was 6.05 (95% CI, 5.82–6.29) deaths per 1000 person-years. The adjusted hazard ratio (HR) for all-cause mortality in all vegetarians combined vs non-vegetarians was 0.88 (95% CI, 0.80–0.97). The adjusted HR for all-cause mortality in vegans was 0.85 (95% CI, 0.73–1.01); in lacto-ovo–vegetarians, 0.91 (95% CI, 0.82–1.00); in pesco-vegetarians, 0.81 (95% CI, 0.69–0.94); and in semi-vegetarians, 0.92 (95% CI, 0.75–1.13) compared with nonvegetarians. Significant associations with vegetarian diets were detected for cardiovascular mortality, noncardiovascular noncancer mortality, renal mortality, and endocrine mortality. Associations in men were larger and more often significant than were those in women. Conclusions and Relevance Vegetarian diets are associated with lower all-cause mortality and with some reductions in cause-specific mortality. Results appeared to be more robust in males. These favorable associations should be considered carefully by those offering dietary guidance.

Arterial function of carotid and brachial arteries in postmenopausal vegetarians

Background: Vegetarianism is associated with a lower risk of cardiovascular disease. However, studies of arterial function in vegetarians are limited. Methods: This study investigated arterial function in vegetarianism by comparing 49 healthy postmenopausal vegetarians with 41 age-matched omnivores. The arterial function of the common carotid artery was assessed by carotid duplex, while the pulse dynamics method was used to measure brachial artery distensibility (BAD), compliance (BAC), and resistance (BAR). Fasting blood levels of glucose, lipids, lipoprotein (a), high-sensitivity C-reactive protein, homocysteine, and vitamin B12 were also measured. Results: Vegetarians had significantly lower serum cholesterol, high-density and low-density lipoprotein, and glucose compared with omnivores. They also had lower vitamin B12 but higher homocysteine levels. Serum levels of lipoprotein (a) and high-sensitivity C-reactive protein were no different between the two groups. There were no significant differences in carotid beta stiffness index, BAC, and BAD between the two groups even after adjustment for associated covariates. However, BAR was significantly lower in vegetarians than in omnivores. Multiple linear regression analysis revealed that age and pulse pressure were two important determinants of carotid beta stiffness index and BAD. Vegetarianism is not associated with better arterial elasticity. Conclusion: Apparently healthy postmenopausal vegetarians are not significantly better in terms of carotid beta stiffness index, BAC, and BAD, but have significantly decreased BAR than omnivores. Prevention of vitamin B12 deficiency might be beneficial for cardiovascular health in vegetarians.

Zinc and selenium nutritional status in vegetarians.

A vegetarian diet may have beneficial effects on human health, however when it is not well-balanced may be deficient in some nutrients, as minerals for example. The aim of the present study was to assess the nutritional status of zinc and selenium in vegetarians in the city of São Paulo. A cross-sectional study was performed, and the inclusion criteria were age > or = 18 years, both gender, no use of food or pharmaceutical supplements. Thirty vegetarian, of both genders, mean age of 27 years and 4.5 years of vegetarianism had performed the study, and their mean BMI was 21.5. Zinc plasma concentration was 71 and 62.5 microg/dL for men and women and erythrocyte concentration was 37 microg/gHb for both genders. Selenium concentration was 73.5 and 77.3 microg/L in plasma and 51.4 and 66.9 microg/L in erythrocytes for men and women, respectively. These biochemical values show that, according to the references, selenium blood levels are adequate and zinc concentration in erythrocytes is deficient in the studied population. For this reason, vegetarians should be constantly assessed and receive nutritional support to reduce the effects of inadequate zinc status.

Insulin sensitivity in Chinese ovo-lactovegetarians compared with omnivores.

AIM: To compare the insulin sensitivity indices between Chinese vegetarians and omnivores. METHODS: The study included 36 healthy volunteers (vegetarian, n=19; omnivore, n=17) who had normal fasting plasma glucose levels. Each participant completed an insulin suppression test. We compared steady-state plasma glucose (SSPG), fasting insulin, the homeostasis model assessment for insulin sensitivity (HOMA-IR and HOMA %S) and beta-cell function (HOMA %beta) between the groups. We also tested the correlation of SSPG with years on a vegetarian diet. RESULTS: The omnivore subjects were younger than the vegetarians (55.7+/-3.7 vs 58.6+/-3.6 year of age, P=0.022). There was no difference between the two groups in sex, blood pressure, renal function tests and lipid profiles. The omnivores had higher serum uric acid levels than vegetarians (5.25+/-0.84 vs 4.54+/-0.75 mg/dl, P=0.011). The results of the indices were different between omnivores and vegetarians (SSPG (mean+/-s.d.) 105.4+/-10.2 vs 80.3+/-11.3 mg/dl, P<0.001; fasting insulin, 4.06+/-0.77 vs 3.02+/-1.19 microU/ml, P=0.004; HOMA-IR, 6.75+/-1.31 vs 4.78+/-2.07, P=0.002; HOMA %S, 159.2+/-31.7 vs 264.3+/-171.7%, P=0.018) except insulin secretion index, HOMA %beta (65.6+/-18.0 vs 58.6+/-14.8%, P=0.208). We found a clear linear relation between years on a vegetarian diet and SSPG (r=-0.541, P=0.017). CONCLUSIONS: The vegetarians were more insulin sensitive than the omnivore counterparts. The degree of insulin sensitivity appeared to be correlated with years on a vegetarian diet.

Homocysteine, circulating vascular cell adhesion molecule and carotid atherosclerosis in postmenopausal vegetarian women and omnivores.

Since the adoption of vegetarian diets as a healthy lifestyle has become popular, the cardiovascular effects of long-term vegetarianism need to be explored. The present study aimed to compare the presence and severity of carotid atherosclerosis (CA), and the blood levels of Vitamin B12, homocysteine (Hcy) and soluble vascular cell adhesion molecule-1 (sVCAM-1) between 57 healthy postmenopausal vegetarians and 61 age-matched omnivores. Carotid atherosclerosis, as measured by ultrasound, was found to be of no significant difference between the two groups. Yet, fasting blood glucose, low-density lipoprotein cholesterol, and Vitamin B12 were significantly lower, while Hcy and sVCAM-1 were higher in the vegetarians as comparing with the omnivores. Multivariate regression analysis showed that the level of Vitamin B12 was negatively associated with the level of Hcy. Vegetarianism itself and Hcy level were significantly associated with sVCAM-1 level in univariate analysis; however, after adjustment for covariates, we identified age but not vegetarianism as the determinant of sVCAM-1 level. Multiple linear regression analysis identified age and systolic blood pressure, but not vegetarianism, as determinants of common carotid artery IMT. In conclusion, there was no significant difference in CA between apparently healthy postmenopausal vegetarians and omnivores. The findings of elevated Hcy in vegetarians indicate the importance of prevention of Vitamin B12 deficiency.

The influence of creatine supplementation on the cognitive functioning of vegetarians and omnivores.

Creatine when combined with P forms phosphocreatine that acts as a reserve of high-energy phosphate. Creatine is found mostly in meat, fish and other animal products, and the levels of muscle creatine are known to be lower in vegetarians. Creatine supplementation influences brain functioning as indicated by imaging studies and the measurement of oxygenated Hb. Given the key role played by creatine in the provision of energy, the influence of its supplementation on cognitive functioning was examined, contrasting the effect in omnivores and vegetarians. Young adult females (n 128) were separated into those who were and were not vegetarian. Randomly and under a double-blind procedure, subjects consumed either a placebo or 20 g of creatine supplement for 5 d. Creatine supplementation did not influence measures of verbal fluency and vigilance. However, in vegetarians rather than in those who consume meat, creatine supplementation resulted in better memory. Irrespective of dietary style, the supplementation of creatine decreased the variability in the responses to a choice reaction-time task.

Dietary protein intake throughout childhood is associated with the timing of puberty.

Early puberty onset is associated with hormone-related cancers, but whether diet in childhood influences pubertal timing is controversial. We examined the association of protein intake in early and mid-childhood with the ages at take-off of the pubertal growth spurt (ATO), peak height velocity (APHV), and menarche in girls and voice break in boys using data from the longitudinal Dortmund Nutritional and Anthropometric Longitudinally Designed Study. Among participants who provided 3-d weighed dietary records at 12 mo, 18-24 mo, 3-4 y, and 5-6 y, 112 had sufficient anthropometric measurements between 6 and 13 y to allow estimation of ATO. Life-course plots were used to identify critical periods of total, animal, and vegetable protein intake (percentage of total energy intake) for pubertal timing. At these ages, the association between tertiles of protein intake (T1-T3) and the outcomes was investigated using multiple linear regression analysis. A higher total and animal protein intake at 5-6 y was related to an earlier ATO. In the highest tertile of animal protein intake at 5-6 y, ATO occurred 0.6 y earlier than in the lowest [(mean, 95% CI) T1: 9.6, 9.4-9.9 vs. T2: 9.4, 9.1-9.7 vs. T3: 9.0, 8.7-9.3 y; P-trend = 0.003, adjusted for sex, total energy, breast-feeding, birth year, and paternal university degree]. Similar findings were seen for APHV (P-trend = 0.001) and the timing of menarche/voice break (P-trend = 0.02). Conversely, a higher vegetable protein intake at 3-4 and 5-6 y was related to later ATO, APHV, and menarche/voice break (P-trend = 0.02-0.04). These results suggest that animal and vegetable protein intake in mid-childhood might be differentially related to pubertal timing.

Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians, and vegans: results from a cross-sectional analysis of the EPIC-Oxford cohort study

Background/Objectives Vegans and to a lesser extent vegetarians have low average circulating concentrations of vitamin B12; however, the relation between factors such as age or time on these diets and vitamin B12 concentrations is not clear. The objectives were to investigate differences in serum vitamin B12 and folate concentrations between omnivores, vegetarians and vegans and to ascertain whether vitamin B12 concentrations differed by age and time on the diet. Subjects/Methods A cross-sectional analysis involving 689 men (226 omnivores, 231 vegetarians and 232 vegans) from the European Prospective Investigation into Cancer and Nutrition Oxford cohort. Results Mean serum vitamin B12 was highest among omnivores (281, 95% CI: 270-292 pmol/l), intermediate in vegetarians (182, 95% CI: 175-189 pmol/l), and lowest in vegans (122, 95% CI: 117-127 pmol/l). Fifty-two percent of vegans, 7% of vegetarians and one omnivore were classified as vitamin B12 deficient (defined as serum vitamin B12 < 118 pmol/l). There was no significant association between age or duration of adherence to a vegetarian or a vegan diet and serum vitamin B12. In contrast, folate concentrations were highest among vegans, intermediate in vegetarians, and lowest in omnivores, but only two men (both omnivores) were categorised as folate deficient (defined as serum folate < 6.3 nmol/l). Conclusion Vegans have lower vitamin B12 concentrations, but higher folate concentrations, than vegetarians and omnivores. Half of the vegans were categorised as vitamin B12 deficient and would be expected to have a higher risk of developing clinical symptoms related to vitamin B12 deficiency.

Relationship of dietary protein and soy isoflavones to serum IGF-1 and IGF binding proteins in the Prostate Cancer Lifestyle Trial.

High levels of insulin-like growth factor 1 (IGF-1) are associated with increased risk of prostate cancer, whereas increased levels of some of its binding proteins (IGFBPs) seem to be protective. High intakes of dietary protein, especially animal and soy protein, appear to increase IGF-1. However, soy isoflavones have demonstrated anti-proliferative and apoptotic effects both in vitro and in vivo. We evaluated dietary intakes of total protein and soy isoflavones in relation to the IGF axis in prostate cancer patients making comprehensive lifestyle changes including a very low-fat vegan diet supplemented with soy protein (58 g/day). After one year, intervention group patients reported significantly higher intakes of dietary protein and soy isoflavones compared to usual-care controls (P < 0.001). IGF-1 increased significantly in both groups, whereas IGFBP-1 rose in the experimental group only (P < 0.01). Increases in vegetable protein over one year were associated with increases in IGFBP-1 among intervention group patients (P < 0.05). These results suggest that dietary protein and soy isoflavones, in the context of comprehensive lifestyle changes, may not significantly alter IGF-1. However, given the recent literature indicating that high intake of protein rich in essential amino acids (animal or soy protein) may increase IGF-1, it may be prudent for men with early stage prostate cancer not to exceed dietary protein recommendations.

Protein intake and ovulatory infertility

Objective To evaluate whether intake of protein from animal and vegetable origin is associated with ovulatory infertility. Study Design 18,555 married women without a history of infertility were followed as they attempted a pregnancy or became pregnant during an eight year period. Dietary assessments were related to the incidence of ovulatory infertility. Results During follow-up, 438 women reported ovulatory infertility. The multivariate-adjusted relative risk [RR] (95% CI; P, trend) of ovulatory infertility comparing the highest to the lowest quintile of animal protein intake was 1.39 (1.01 – 1.90; 0.03). The corresponding RR (95% CI; P, trend) for vegetable protein intake was 0.78 (0.54 – 1.12; 0.07). Further, consuming 5% of total energy intake as vegetable protein rather than as animal protein was associated with a more than 50% lower risk of ovulatory infertility (P = 0.007). Conclusions Replacing animal sources of protein with vegetable sources of protein may reduce ovulatory infertility risk.

Could a vegetarian diet reduce exercise-induced oxidative stress? A review of the literature.

Oxidative stress is a natural physiological process that describes an imbalance between free radical production and the ability of the antioxidant defence system of the body to neutralize free radicals. Free radicals can be beneficial as they may promote wound healing and contribute to a healthy immune response. However, free radicals can have a detrimental impact when they interfere with the regulation of apoptosis and thus play a role in the promotion of some cancers and conditions such as cardiovascular disease. Antioxidants are molecules that reduce the damage associated with oxidative stress by counteracting free radicals. Regular exercise is a vital component of a healthy lifestyle, although it can increase oxidative stress. As a typical vegetarian diet comprises a wide range of antioxidant-rich foods, it is plausible that the consumption of these foods will result in an enhanced antioxidant system capable of reducing exercise-induced oxidative stress. In addition, a relationship between a vegetarian diet and lower risks of cardiovascular disease and some cancers has been established. This review explores the current available evidence linking exercise, vegetarians, antioxidants, and oxidative stress.

The incidence of dementia and intake of animal products: preliminary findings from the Adventist Health Study.

We investigated the relationship between animal product consumption and evidence of dementia in two cohort substudies. The first enrolled 272 California residents matched for age, sex, and zip code (1 vegan, 1 lacto-ovo-vegetarian, and 2 'heavy' meat eaters in each of 68 quartets). This design ensured a wide range of dietary exposure. The second included 2,984 unmatched subjects who resided within the Loma Linda, California area. All subjects were enrolled in the Adventist Health Study. The matched subjects who ate meat (including poultry and fish) were more than twice as likely to become demented as their vegetarian counterparts (relative risk 2.18, p = 0.065) and the discrepancy was further widened (relative risk 2.99, p = 0.048) when past meat consumption was taken into account. There was no significant difference in the incidence of dementia in the vegetarian versus meat-eating unmatched subjects. There was no obvious explanation for the difference between the two substudies, although the power of the unmatched sub-study to detect an effect of 'heavy' meat consumption was unexpectedly limited. There was a trend towards delayed onset of dementia in vegetarians in both substudies.

Prevalence of urinary stone disease in vegetarians.

A study was carried out to determine the effect of a low animal protein diet, such as taken by vegetarians, on the risk of urinary stone disease. A nation-wide survey of vegetarians in the UK showed that the prevalence of urinary stone formation is 40-60% of that predicted for a group of individuals taken from the general population and matched for age, sex and social class with the vegetarians. The findings support the hypothesis that a diet low in animal protein reduces the risk of urinary stone formation.

Type of Vegetarian Diet, Body Weight, and Prevalence of Type 2 Diabetes

OBJECTIVE We assessed the prevalence of type 2 diabetes in people following different types of vegetarian diets compared with that in nonvegetarians. RESEARCH DESIGN AND METHODS The study population comprised 22,434 men and 38,469 women who participated in the Adventist Health Study-2 conducted in 2002–2006. We collected self-reported demographic, anthropometric, medical history, and lifestyle data from Seventh-Day Adventist church members across North America. The type of vegetarian diet was categorized based on a food-frequency questionnaire. We calculated odds ratios (ORs) and 95% CIs using multivariate-adjusted logistic regression. RESULTS Mean BMI was lowest in vegans (23.6 kg/m2) and incrementally higher in lacto-ovo vegetarians (25.7 kg/m2), pesco-vegetarians (26.3 kg/m2), semi-vegetarians (27.3 kg/m2), and nonvegetarians (28.8 kg/m2). Prevalence of type 2 diabetes increased from 2.9% in vegans to 7.6% in nonvegetarians; the prevalence was intermediate in participants consuming lacto-ovo (3.2%), pesco (4.8%), or semi-vegetarian (6.1%) diets. After adjustment for age, sex, ethnicity, education, income, physical activity, television watching, sleep habits, alcohol use, and BMI, vegans (OR 0.51 [95% CI 0.40–0.66]), lacto-ovo vegetarians (0.54 [0.49–0.60]), pesco-vegetarians (0.70 [0.61–0.80]), and semi-vegetarians (0.76 [0.65–0.90]) had a lower risk of type 2 diabetes than nonvegetarians. CONCLUSIONS The 5-unit BMI difference between vegans and nonvegetarians indicates a substantial potential of vegetarianism to protect against obesity. Increased conformity to vegetarian diets protected against risk of type 2 diabetes after lifestyle characteristics and BMI were taken into account. Pesco- and semi-vegetarian diets afforded intermediate protection.

Original Articles: Vegetarian Compared with Meat Dietary Protein Source and Phosphorus Homeostasis in Chronic Kidney Disease

Summary Background and objectives Patients with advanced chronic kidney disease (CKD) are in positive phosphorus balance, but phosphorus levels are maintained in the normal range through phosphaturia induced by increases in fibroblast growth factor-23 (FGF23) and parathyroid hormone (PTH). This provides the rationale for recommendations to restrict dietary phosphate intake to 800 mg/d. However, the protein source of the phosphate may also be important. Design, setting, participants, & measurements We conducted a crossover trial in nine patients with a mean estimated GFR of 32 ml/min to directly compare vegetarian and meat diets with equivalent nutrients prepared by clinical research staff. During the last 24 hours of each 7-day diet period, subjects were hospitalized in a research center and urine and blood were frequently monitored. Results The results indicated that 1 week of a vegetarian diet led to lower serum phosphorus levels and decreased FGF23 levels. The inpatient stay demonstrated similar diurnal variation for blood phosphorus, calcium, PTH, and urine fractional excretion of phosphorus but significant differences between the vegetarian and meat diets. Finally, the 24-hour fractional excretion of phosphorus was highly correlated to a 2-hour fasting urine collection for the vegetarian diet but not the meat diet. Conclusions In summary, this study demonstrates that the source of protein has a significant effect on phosphorus homeostasis in patients with CKD. Therefore, dietary counseling of patients with CKD must include information on not only the amount of phosphate but also the source of protein from which the phosphate derives.

Effect of ingestion of meat on plasma cholesterol of vegetarians.

In a controlled trial, 21 strict vegetarians were studied prospectively for eight weeks: a two-week control period of the usual vegetarian diet was followed by four weeks, during which 250 g of beef was added isocalorically to the daily vegetarian diet and then by two weeks of the control diet. Plasma high-density lipoprotein-cholesterol did not change during the study, whereas plasma total cholesterol rose significantly by 19% at the end of the meat-eating period. Systolic blood pressure (BP) increased significantly during the meat eating by 3% over control values, whereas diastolic BP showed no major changes. Plasma renin activity, prostaglandin A and E levels, and urinary kallikrein, norepinephrine, and epinephrine excretions were within normal limits and did not change notably throughout the trial. The study suggests an adverse effect of consumption of beef on plasma lipid and BP levels.

Cardiovascular disease mortality and cancer incidence in vegetarians: a meta-analysis and systematic review.

BACKGROUND: Prospective cohort studies have examined mortality and overall cancer incidence among vegetarians, but the results have been inconclusive. AIMS: The objective of the present meta-analysis was to investigate cardiovascular disease mortality and cancer incidence among vegetarians and nonvegetarians. METHODS: Medline, EMBASE and Web Of Science databases were searched for cohort studies published from inception to September 2011. Studies were included if they contained the relative risk (RR) and corresponding 95% CI. Participants were from the UK, Germany, California, USA, the Netherlands and Japan. RESULTS: Seven studies with a total of 124,706 participants were included in this analysis. All-cause mortality in vegetarians was 9% lower than in nonvegetarians (RR = 0.91; 95% CI, 0.66-1.16). The mortality from ischemic heart disease was significantly lower in vegetarians than in nonvegetarians (RR = 0.71; 95% CI, 0.56-0.87). We observed a 16% lower mortality from circulatory diseases (RR = 0.84; 95% CI, 0.54-1.14) and a 12% lower mortality from cerebrovascular disease (RR = 0.88; 95% CI, 0.70-1.06) in vegetarians compared with nonvegetarians. Vegetarians had a significantly lower cancer incidence than nonvegetarians (RR = 0.82; 95% CI, 0.67-0.97). CONCLUSIONS: Our results suggest that vegetarians have a significantly lower ischemic heart disease mortality (29%) and overall cancer incidence (18%) than nonvegetarians. Copyright © 2012 S. Karger AG, Basel.

Plant and animal protein intake and its association with overweight and obesity among the Belgian population.

The objective of the present study was to assess animal and plant protein intakes in the Belgian population and to examine their relationship with overweight and obesity (OB). The subjects participated in the Belgian National Food Consumption Survey conducted in 2004. Food consumption was assessed by using two non-consecutive 24 h dietary recalls. About 3083 participants ( ≥ 15 years of age; 1546 males, 1537 females) provided completed dietary information. Animal protein intake (47 g/d) contributed more to total protein intakes of 72 g/d than plant protein intake, which accounted for 25 g/d. Meat and meat products were the main contributors to total animal protein intakes (53 %), whereas cereals and cereal products contributed most to plant protein intake (54 %). Males had higher animal and plant protein intakes than females (P < 0·001). Legume and soya protein intakes were low in the whole population (0·101 and 0·174 g/d, respectively). In males, animal protein intake was positively associated with BMI (β = 0·013; P = 0·001) and waist circumference (WC; β = 0·041; P = 0·002). Both in males and females, plant protein intake was inversely associated with BMI (males: β = - 0·036; P < 0·001; females: β = - 0·046; P = 0·001) and WC (male: β = - 0·137; P < 0·001; female: β = - 0·096; P = 0·024). In conclusion, plant protein intakes were lower than animal protein intakes among a representative sample of the Belgian population and decreased with age. Associations with anthropometric data indicated that plant proteins could offer a protective effect in the prevention of overweight and OB in the Belgian population.

Vegetarian diets and incidence of diabetes in the Adventist Health Study-2

Aim To evaluate the relationship of diet to incident diabetes among non-Black and Black participants in the Adventist Health Study-2. Methods and Results Participants were 15,200 men and 26,187 women (17.3% Blacks) across the U.S. and Canada who were free of diabetes and who provided demographic, anthropometric, lifestyle and dietary data. Participants were grouped as vegan, lacto ovo vegetarian, pesco vegetarian, semi-vegetarian or non-vegetarian (reference group). A follow-up questionnaire after two years elicited information on the development of diabetes. Cases of diabetes developed in 0.54% of vegans, 1.08% of lacto ovo vegetarians, 1.29% of pesco vegetarians, 0.92% of semi-vegetarians and 2.12% of non-vegetarians. Blacks had an increased risk compared to non-Blacks (odds ratio [OR] 1.364; 95% confidence interval [CI], 1.093–1.702). In multiple logistic regression analysis controlling for age, gender, education, income, television watching, physical activity, sleep, alcohol use, smoking and BMI, vegans (OR 0.381; 95% CI 0.236–0.617), lacto ovo vegetarians (OR 0.618; 95% CI 0.503–0.760) and semi-vegetarians (OR 0.486, 95% CI 0.312–0.755) had a lower risk of diabetes than non-vegetarians. In non-Blacks vegan, lacto ovo and semi-vegetarian diets were protective against diabetes (OR 0.429, 95% CI 0.249–0.740; OR 0.684, 95% CI 0.542–0.862; OR 0.501, 95% CI 0.303–0.827); among Blacks vegan and lacto ovo vegetarian diets were protective (OR 0.304, 95% CI 0.110–0.842; OR 0.472, 95% CI 0.270–0.825). These associations were strengthened when BMI was removed from the analyses. Conclusion Vegetarian diets (vegan, lacto ovo, semi-) were associated with a substantial and independent reduction in diabetes incidence. In Blacks the dimension of the protection associated with vegetarian diets was as great as the excess risk associated with Black ethnicity.

Veganism, bone mineral density, and body composition: a study in Buddhist nuns.

SUMMARY: This cross-sectional study showed that, although vegans had lower dietary calcium and protein intakes than omnivores, veganism did not have adverse effect on bone mineral density and did not alter body composition. INTRODUCTION: Whether a lifelong vegetarian diet has any negative effect on bone health is a contentious issue. We undertook this study to examine the association between lifelong vegetarian diet and bone mineral density and body composition in a group of postmenopausal women. METHODS: One hundred and five Mahayana Buddhist nuns and 105 omnivorous women (average age = 62, range = 50-85) were randomly sampled from monasteries in Ho Chi Minh City and invited to participate in the study. By religious rule, the nuns do not eat meat or seafood (i.e., vegans). Bone mineral density (BMD) at the lumbar spine (LS), femoral neck (FN), and whole body (WB) was measured by DXA (Hologic QDR 4500). Lean mass, fat mass, and percent fat mass were also obtained from the DXA whole body scan. Dietary calcium and protein intakes were estimated from a validated food frequency questionnaire. RESULTS: There was no significant difference between vegans and omnivores in LSBMD (0.74 +/- 0.14 vs. 0.77 +/- 0.14 g/cm(2); mean +/- SD; P = 0.18), FNBMD (0.62 +/- 0.11 vs. 0.63 +/- 0.11 g/cm(2); P = 0.35), WBBMD (0.88 +/- 0.11 vs. 0.90 +/- 0.12 g/cm(2); P = 0.31), lean mass (32 +/- 5 vs. 33 +/- 4 kg; P = 0.47), and fat mass (19 +/- 5 vs. 19 +/- 5 kg; P = 0.77) either before or after adjusting for age. The prevalence of osteoporosis (T scores < or = -2.5) at the femoral neck in vegans and omnivores was 17.1% and 14.3% (P = 0.57), respectively. The median intake of dietary calcium was lower in vegans compared to omnivores (330 +/- 205 vs. 682 +/- 417 mg/day, P < 0.001); however, there was no significant correlation between dietary calcium and BMD. Further analysis suggested that whole body BMD, but not lumbar spine or femoral neck BMD, was positively correlated with the ratio of animal protein to vegetable protein. CONCLUSION: These results suggest that, although vegans have much lower intakes of dietary calcium and protein than omnivores, veganism does not have adverse effect on bone mineral density and does not alter body composition.

Nutrient Profiles of Vegetarian and Non Vegetarian Dietary Patterns

Background Differences in nutrient profiles between vegetarian and non vegetarian dietary patterns reflect nutritional differences that may contribute to the development of disease. Objective To compare nutrient intakes between dietary patterns characterized by consumption or exclusion of meat and dairy products. Design Cross-sectional study of 71751 subjects (mean age 59 years) from the Adventist-Health-Study-2. Data was collected between 2002 and 2007. Participants completed a 204-item validated semi-quantitative food frequency questionnaire. Dietary patterns compared were: non vegetarian, semi vegetarian, pesco vegetarian, lacto-ovo vegetarian and strict vegetarian. ANCOVA was used to analyze differences in nutrient intakes by dietary patterns and were adjusted for age, and sex and race. BMI and other relevant demographic data were reported and compared by dietary pattern using chi-square tests and ANOVA. Results Many nutrient intakes varied significantly between dietary patterns. Non vegetarians had the lowest intakes of plant proteins, fiber, β-Carotene, and Mg than those following vegetarian dietary patterns and the highest intakes of saturated, trans, arachidonic, and docosahexaenoic fatty acids. The lower tails of some nutrient distributions in strict vegetarians suggested inadequate intakes by a portion of the subjects. Energy intake was similar among dietary patterns at close to 2000 kcal/d with the exception of semi vegetarians that had an intake of 1713 kcal/d. Mean BMI was highest in non-vegetarians (mean; standard deviation [SD]) (28.7; [6.4]) and lowest in strict vegetarians (24.0; [4.8]). Conclusions Nutrient profiles varied markedly between dietary patterns that were defined by meat and dairy intakes. These differences can be of interest in the etiology of obesity and chronic diseases.

No evidence of insulin resistance in normal weight vegetarians. A case control study.

BACKGROUND: Diets rich in carbohydrates with a low glycemic index and with high fiber content are associated with flat post-prandial rises of blood glucose, minimal post-prandial insulin secretion and maintenance of insulin sensitivity. Protective food commodities in the prevention of cardiovascular disease, insulin resistance syndrome or diabetes are crucial components of the vegetarian diet. AIM OF THE STUDY: Insulin resistance values were assessed in relation to different nutrition. Metabolic abnormality is a predictor of age-related diseases and can be more pronounced in obese subjects. Insulin resistance values in normal weight subjects of two different nutritional habits were correlated with age. METHODS: Fasting concentrations of glucose and insulin as well as calculated values of insulin resistance IR (HOMA) were assessed in two nutritional groups of apparently healthy adult subjects (age range 19 - 64 years) with normal weight (body mass index 18.6 - 25.0 kg/m(2)): a vegetarian group (95 long-term lacto-ovo-vegetarians; duration of vegetarianism 10.2 +/- 0.5 years) and a non-vegetarian control group (107 subjects of general population on traditional western diet). Intake of energy and main nutrients (fats, saccharides, proteins) was similar in both groups. RESULTS: Glucose and insulin concentrations and IR (HOMA) values were significantly lower in vegetarians (glucose 4.47 +/- 0.05 vs. 4.71 +/- 0.07 mmol/l; insulin 4.96 +/- 0.23 vs. 7.32 +/- 0.41 mU/l; IR (HOMA) 0.99 +/- 0.05 vs. 1.59 +/- 0.10). IR (HOMA) dependence on age was only significant in subjects on a western diet. A significant increase of IR was found already in the age range 31-40 years, compared to vegetarians and it continued in later age decades. Age independent and low insulin resistance values in vegetarians are a consequence of an effective diet prevention by long-term frequent consumption of protective food. Vegetarians had a significantly higher consumption of whole grain products, pulses, products from oat and barley. CONCLUSION: The results of age independent and low values of insulin resistance document a beneficial effect of long-term vegetarian nutrition in prevention of metabolic syndrome, diabetes and cardiovascular disease.

Vegetarian diets and blood pressure among white subjects: results from the Adventist Health Study-2 (AHS-2)

Objective Previous work studying vegetarians has often found that they have lower blood pressure (BP). Reasons may include their lower BMI and higher intake levels of fruit and vegetables. Here we seek to extend this evidence in a geographically diverse population containing vegans, lacto-ovo vegetarians and omnivores. Design Data are analysed from a calibration sub-study of the Adventist Health Study-2 (AHS-2) cohort who attended clinics and provided validated FFQ. Criteria were established for vegan, lacto-ovo vegetarian, partial vegetarian and omnivorous dietary patterns. Setting Clinics were conducted at churches across the USA and Canada. Dietary data were gathered by mailed questionnaire. Subjects Five hundred white subjects representing the AHS-2 cohort. Results Covariate-adjusted regression analyses demonstrated that the vegan vegetarians had lower systolic and diastolic BP (mmHg) than omnivorous Adventists (β =−6·8, P<0·05 and β = −6·9, P<0·001). Findings for lacto-ovo vegetarians (β = −9·1, P<0·001 and β = −5·8, P<0·001) were similar. The vegetarians (mainly the vegans) were also less likely to be using antihypertensive medications. Defining hypertension as systolic BP > 139 mmHg or diastolic BP > 89 mmHg or use of antihypertensive medications, the odds ratio of hypertension compared with omnivores was 0·37 (95 % CI 0·19, 0·74), 0·57 (95 % CI 0·36, 0·92) and 0·92 (95 % CI 0·50, 1·70), respectively, for vegans, lacto-ovo vegetarians and partial vegetarians. Effects were reduced after adjustment for BMI. Conclusions We conclude from this relatively large study that vegetarians, especially vegans, with otherwise diverse characteristics but stable diets, do have lower systolic and diastolic BP and less hypertension than omnivores. This is only partly due to their lower body mass.

IQ in childhood and vegetarianism in adulthood: 1970 British cohort study

Objective To examine the relation between IQ in childhood and vegetarianism in adulthood. Design Prospective cohort study in which IQ was assessed by tests of mental ability at age 10 years and vegetarianism by self-report at age 30 years. Setting Great Britain. Participants 8170 men and women aged 30 years participating in the 1970 British cohort study, a national birth cohort. Main outcome measures Self-reported vegetarianism and type of diet followed. Results 366 (4.5%) participants said they were vegetarian, although 123 (33.6%) admitted eating fish or chicken. Vegetarians were more likely to be female, to be of higher social class (both in childhood and currently), and to have attained higher academic or vocational qualifications, although these socioeconomic advantages were not reflected in their income. Higher IQ at age 10 years was associated with an increased likelihood of being vegetarian at age 30 (odds ratio for one standard deviation increase in childhood IQ score 1.38, 95% confidence interval 1.24 to 1.53). IQ remained a statistically significant predictor of being vegetarian as an adult after adjustment for social class (both in childhood and currently), academic or vocational qualifications, and sex (1.20, 1.06 to 1.36). Exclusion of those who said they were vegetarian but ate fish or chicken had little effect on the strength of this association. Conclusion Higher scores for IQ in childhood are associated with an increased likelihood of being a vegetarian as an adult.

Cancer in British vegetarians: updated analyses of 4998 incident cancers in a cohort of 32,491 meat eaters, 8612 fish eaters, 18,298 vegetarians, and 2246 vegans

Background: Vegetarian diets might affect the risk of cancer. Objective: The objective was to describe cancer incidence in vegetarians and nonvegetarians in a large sample in the United Kingdom. Design: This was a pooled analysis of 2 prospective studies including 61,647 British men and women comprising 32,491 meat eaters, 8612 fish eaters, and 20,544 vegetarians (including 2246 vegans). Cancer incidence was followed through nationwide cancer registries. Cancer risk by vegetarian status was estimated by using multivariate Cox proportional hazards models. Results: After an average follow-up of 14.9 y, there were 4998 incident cancers: 3275 in meat eaters (10.1%), 520 in fish eaters (6.0%), and 1203 in vegetarians (5.9%). There was significant heterogeneity between dietary groups in risks of the following cancers: stomach cancer [RRs (95% CIs) compared with meat eaters: 0.62 (0.27, 1.43) in fish eaters and 0.37 (0.19, 0.69) in vegetarians; P-heterogeneity = 0.006], colorectal cancer [RRs (95% CIs): 0.66 (0.48, 0.92) in fish eaters and 1.03 (0.84, 1.26) in vegetarians; P-heterogeneity = 0.033], cancers of the lymphatic and hematopoietic tissue [RRs (95% CIs): 0.96 (0.70, 1.32) in fish eaters and 0.64 (0.49, 0.84) in vegetarians; P-heterogeneity = 0.005], multiple myeloma [RRs (95% CIs): 0.77 (0.34, 1.76) in fish eaters and 0.23 (0.09, 0.59) in vegetarians; P-heterogeneity = 0.010], and all sites combined [RRs (95% CIs): 0.88 (0.80, 0.97) in fish eaters and 0.88 (0.82, 0.95) in vegetarians; P-heterogeneity = 0.0007]. Conclusion: In this British population, the risk of some cancers is lower in fish eaters and vegetarians than in meat eaters.

Diet, vegetarianism, and cataract risk.

BACKGROUND: Age-related cataract is a major cause of morbidity. Previous studies of diet and cataract risk have focused on specific nutrients or healthy eating indexes but not on identifiable dietary groups such as vegetarians. OBJECTIVE: We investigated the association between diet and cataract risk in a population that has a wide range of diets and includes a high proportion of vegetarians. DESIGN: We used Cox proportional hazards regression to study cataract risk in relation to baseline dietary and lifestyle characteristics of 27,670 self-reported nondiabetic participants aged ≥40 y at recruitment in the Oxford (United Kingdom) arm of the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford) by using data from the Hospital Episode Statistics in England and Scottish Morbidity Records. RESULTS: There was a strong relation between cataract risk and diet group, with a progressive decrease in risk of cataract in high meat eaters to low meat eaters, fish eaters (participants who ate fish but not meat), vegetarians, and vegans. After multivariable adjustment, incidence rate ratios (95% CIs) for moderate meat eaters (50-99 g meat/d), low meat eaters (<50 g meat/d), fish eaters, vegetarians, and vegans compared with high-meat eaters (≥100 g meat/d) were 0.96 (0.84, 1.11), 0.85 (0.72, 0.99), 0.79 (0.65, 0.97), 0.70 (0.58, 0.84), and 0.60 (0.38, 0.96), respectively (P < 0.001 for heterogeneity). Associations between cataract risk and intakes of selected nutrients and foods generally reflected the strong association with diet group. CONCLUSION: Vegetarians were at lower risk of cataract than were meat eaters in this cohort of health-conscious British residents.

Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford.

OBJECTIVE: To compare fracture rates in four diet groups (meat eaters, fish eaters, vegetarians and vegans) in the Oxford cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford). DESIGN: Prospective cohort study of self-reported fracture risk at follow-up. SETTING: The United Kingdom. SUBJECTS: A total of 7947 men and 26,749 women aged 20-89 years, including 19,249 meat eaters, 4901 fish eaters, 9420 vegetarians and 1126 vegans, recruited by postal methods and through general practice surgeries. METHODS: Cox regression. RESULTS: Over an average of 5.2 years of follow-up, 343 men and 1555 women reported one or more fractures. Compared with meat eaters, fracture incidence rate ratios in men and women combined adjusted for sex, age and non-dietary factors were 1.01 (95% CI 0.88-1.17) for fish eaters, 1.00 (0.89-1.13) for vegetarians and 1.30 (1.02-1.66) for vegans. After further adjustment for dietary energy and calcium intake the incidence rate ratio among vegans compared with meat eaters was 1.15 (0.89-1.49). Among subjects consuming at least 525 mg/day calcium the corresponding incidence rate ratios were 1.05 (0.90-1.21) for fish eaters, 1.02 (0.90-1.15) for vegetarians and 1.00 (0.69-1.44) for vegans. CONCLUSIONS: In this population, fracture risk was similar for meat eaters, fish eaters and vegetarians. The higher fracture risk in the vegans appeared to be a consequence of their considerably lower mean calcium intake. An adequate calcium intake is essential for bone health, irrespective of dietary preferences. SPONSORSHIP: The EPIC-Oxford study is supported by The Medical Research Council and Cancer Research UK.

Vegetarian vs nonvegetarian diets, dietary restraint, and subclinical ovulatory disturbances: prospective 6-mo study.

Ovulatory function was prospectively assessed over 6 mo in 23 vegetarians and 22 nonvegetarians with clinically normal menstrual cycles. Subjects were 20-40 y of age, of stable weight (body mass index, in kg/m2, of 18-25), on current diets for > or = 2 y, and not using oral contraceptives. Quantitative analysis of basal body temperature records classified cycles as normally ovulatory, short luteal phase (< 10 d), or anovulatory. Subjects completed the Three-Factor Eating Questionnaire (subjects completed the Three-Factor Eating Questionnaire (subscales for restraint, hunger, and disinhibition) and kept three 3-d food records. Vegetarians had lower BMIs (21.1 +/- 2.3 vs 22.7 +/- 1.9, P < 0.05), percentage body fat (24.0 +/- 5.5% vs 27.4 +/- 5.1%, P < 0.05), and restraint scores (6.4 +/- 4.4 vs 9.5 +/- 3.7, P < 0.05). Mean cycle lengths were similar, but vegetarians had longer luteal phase lengths (11.2 +/- 2.6 vs 9.1 +/- 3.8 d, P < 0.05). Cycle types also differed (chi 2 = 9.64, P < 0.01): vegetarians had fewer anovulatory cycles (4.6% vs 15.1% of cycles). Compared with those with restraint scores below the median, highly restrained women had fewer ovulatory cycles (3.6 +/- 2.3 vs 5.0 +/- 1.4, P < 0.05) and shorter mean luteal phase lengths (7.4 +/- 4.1 vs 10.7 +/- 3.1 d, P < 0.05). We conclude that ovulatory disturbances and restrained eating are less common among vegetarians, and that restraint influences ovulatory function.

Does a vegan diet reduce risk for Parkinson's disease?

Three recent case-control studies conclude that diets high in animal fat or cholesterol are associated with a substantial increase in risk for Parkinson's disease (PD); in contrast, fat of plant origin does not appear to increase risk. Whereas reported age-adjusted prevalence rates of PD tend to be relatively uniform throughout Europe and the Americas, sub-Saharan black Africans, rural Chinese, and Japanese, groups whose diets tend to be vegan or quasi-vegan, appear to enjoy substantially lower rates. Since current PD prevalence in African-Americans is little different from that in whites, environmental factors are likely to be responsible for the low PD risk in black Africans. In aggregate, these findings suggest that vegan diets may be notably protective with respect to PD. However, they offer no insight into whether saturated fat, compounds associated with animal fat, animal protein, or the integrated impact of the components of animal products mediates the risk associated with animal fat consumption. Caloric restriction has recently been shown to protect the central dopaminergic neurons of mice from neurotoxins, at least in part by induction of heat-shock proteins; conceivably, the protection afforded by vegan diets reflects a similar mechanism. The possibility that vegan diets could be therapeutically beneficial in PD, by slowing the loss of surviving dopaminergic neurons, thus retarding progression of the syndrome, may merit examination. Vegan diets could also be helpful to PD patients by promoting vascular health and aiding blood-brain barrier transport of L-dopa. Copyright 2001 Harcourt Publishers Ltd.

Comparison of Nutritional Quality of the Vegan, Vegetarian, Semi-Vegetarian, Pesco-Vegetarian and Omnivorous Diet

The number of studies comparing nutritional quality of restrictive diets is limited. Data on vegan subjects are especially lacking. It was the aim of the present study to compare the quality and the contributing components of vegan, vegetarian, semi-vegetarian, pesco-vegetarian and omnivorous diets. Dietary intake was estimated using a cross-sectional online survey with a 52-items food frequency questionnaire (FFQ). Healthy Eating Index 2010 (HEI-2010) and the Mediterranean Diet Score (MDS) were calculated as indicators for diet quality. After analysis of the diet questionnaire and the FFQ, 1475 participants were classified as vegans (n = 104), vegetarians (n = 573), semi-vegetarians (n = 498), pesco-vegetarians (n = 145), and omnivores (n = 155). The most restricted diet, i.e., the vegan diet, had the lowest total energy intake, better fat intake profile, lowest protein and highest dietary fiber intake in contrast to the omnivorous diet. Calcium intake was lowest for the vegans and below national dietary recommendations. The vegan diet received the highest index values and the omnivorous the lowest for HEI-2010 and MDS. Typical aspects of a vegan diet (high fruit and vegetable intake, low sodium intake, and low intake of saturated fat) contributed substantially to the total score, independent of the indexing system used. The score for the more prudent diets (vegetarians, semi-vegetarians and pesco-vegetarians) differed as a function of the used indexing system but they were mostly better in terms of nutrient quality than the omnivores.

Cadmium blood concentrations in relation to nutrition.

Cadmium is a toxic element ubiquitous in the environment, which damages biological systems in various ways. The major source of cadmium exposure is food. High cadmium content in the soil leads to high cadmium concentrations in certain plants such as grains (above all surface layers and germs), oil or non-oil seeds, fruit and vegetables. These food commodities are the crucial components of a vegetarian nutrition. Blood cadmium concentrations were measured in two non-smoking population groups: the vegetarian group (n = 80) and the non-vegetarian (control) group of general population on traditional mixed diet (n = 84). The significantly higher blood cadmium content (1.78 +/- 0.22 vs. 0.45 +/- 0.04 microg/l) was measured in vegetarian group. Healthy risk values > 5 microg/l were found in 6 vegetarians vs. no non-vegetarian. The highest cadmium concentration (3.15 +/- 0.77 microg/l) was measured in vegan subgroup (plant food only, n = 10) and that value decreased with increasing animal food consumption (1.75 +/- 0.36 microg/l, lactovegetarian and lactoovovegetarian subgroup/added dairy products and eggs, n = 41/, 1.34 +/- 0.21 microg/I, semivegetarian subgroup /as a previous subgroup and added white meat, n = 291). Risk vegetarians vs. non-risk vegetarians consume significantly higher amounts of whole grain products, grain sprouts and oil seeds. Blood cadmium content is directly influenced by age (r = 0.32, p < 0.001), by whole grain product intake (r = 0.66, p < 0.001) and by duration of vegetarianism (r = 0.5, p < 0.001). Oxidative stress plays a major role in chronic cadmium induced hepatic and renal toxicity as well as in other consequences of cadmium injuries. Vegetarians have significantly higher plasma concentrations of natural antioxidants. The sufficient antioxidative protection against cadmium induced free radical formation in vegetarians may inhibit the harmful effects of greater cadmium intake from plant food.

Hypocholesterolemic effect of substituting soybean protein for animal protein in the diet of healthy young women.

The effect of dietary protein on the level of plasma cholesterol in young, healthy, normolipidemic women was investigated in two separate studies by feeding either a conventional diet containing mixed protein, or a plant protein diet in which the animal protein of the first diet was replaced by soy protein meat analogues and soy milk. The diets were similar with respect to carbohydrate, fat and sterol composition. The first study, lasting 73 days and involving six subjects, gave an indication that plasma cholesterol levels were lower on the plant protein diet. The second study, which incorporated a number of improvements based on experience, lasted 78 days and used a cross-over design involving two groups of five subjects each. In this study, the mean plasma cholesterol level was found to be significantly lower on the plant protein diet.

Longitudinal association between animal and vegetable protein intake and obesity among adult males in the United States: the Chicago Western Electric Study

Literature on the association of protein intake with body weight is inconsistent. Little is known about the relation of long-term protein intake to obesity. This study aimed to determine the association between protein intake and obesity. A cohort of 1,730 employed white men ages 40–55 years from the Chicago Western Electric Study was followed from 1958 to 1966. Diet was assessed twice with Burke’s comprehensive diet history method, at two baseline examinations; height, weight, and other covariates were measured annually by trained interviewers. Generalized estimating equation (GEE) was used to examine the relation of baseline total, animal, and vegetable protein intake to likelihood of being overweight or obese at sequential annual examinations. Dietary animal protein was positively related to overweight and obesity over seven years of follow up. With adjustment for potential confounders (age, education, cigarette smoking, alcohol intake, energy, carbohydrate and saturated fat intake, and history of diabetes or other chronic disease), the odds ratios (95% confidence intervals) for obesity were 4.62 (2.68–7.98, p for trend<0.01) for participants in the highest compared to the lowest quartile of animal protein and 0.58 (0.36, 0.95, p for trend=0.053) for those in the highest quartile of vegetable protein intake. A statistically significant, positive association was seen between animal protein intake and obesity; those in higher quartiles of vegetable protein intake had lower odds of being obese. These results indicate that animal and vegetable protein may relate differently to occurrence of obesity in the long run.

Vegetarian diets and public health: biomarker and redox connections.

Vegetarian diets are rich in antioxidant phytochemicals. However, they may not act as antioxidants in vivo, and yet still have important signaling and regulatory functions. Some may act as pro-oxidants, modulating cellular redox tone and oxidizing redox sensitive sites. In this review, evidence for health benefits of vegetarian diets is presented from different perspectives: epidemiological, biomarker, evolutionary, and public health, as well as antioxidant. From the perspective of molecular connections between diet and health, evidence of a role for plasma ascorbic acid as a biomarker for future disease risk is presented. Basic concepts of redox-based cell signaling are presented, and effects of antioxidant phytochemicals on signaling, especially via redox tone, sulfur switches and the Antioxidant Response Element (ARE), are explored. Sufficient scientific evidence exists for public health policy to promote a plant-rich diet for health promotion. This does not need to wait for science to provide all the answers as to why and how. However, action and interplay of dietary antioxidants in the nonequilibrium systems that control redox balance, cell signaling, and cell function provide rich ground for research to advance understanding of orthomolecular nutrition and provide science-based evidence to advance public health in our aging population.

Should recurrent calcium oxalate stone formers become vegetarians?

The hypothesis that the incidence of calcium stone disease is related to the consumption of animal protein has been examined. Within the male population, recurrent idiopathic stone formers consumed more animal protein than did normal subjects. Single stone formers had animal protein intakes intermediate between those of normal men and those of recurrent stone formers. A high animal protein intake caused a significant increase in the urinary excretion of calcium, oxalate and uric acid, 3 of the 6 main urinary risk factors for calcium stone formation. The overall relative probability of forming stones, calculated from the combination of the 6 main urinary risk factors, was markedly increased by a high animal protein diet. Conversely, a low animal protein intake, such as taken by vegetarians, was associated with a low excretion of calcium, oxalate and uric acid and a low relative probability of forming stones.

Nutritional quality of legumes, and their role in cardiometabolic risk prevention: a review.

Legumes (including alfalfa, clover, lupins, green beans and peas, peanuts, soybeans, dry beans, broad beans, dry peas, chickpeas, and lentils) represent an important component of the human diet in several areas of the world, especially in the developing countries, where they complement the lack of proteins from cereals, roots, and tubers. In some regions of the world, legume seeds are the only protein supply in the diet. The health benefits of legume consumption have received rising interest from researchers, and their consumption and production extends worldwide. Among European countries, higher legume consumption is observed around the Mediterranean, with per capita daily consumption between 8 and 23 g, while in Northern Europe, the daily consumption is less than 5 g per capita. The physiological effects of different legumes vary significantly. These differences may result from the polysaccharides composition, in particular, the quantity and variety of dietary fibers and starch, protein make-up, and variability in phytochemical content. The majority of legumes contain phytochemicals: bioactive compounds, including enzyme inhibitors, phytohemagglutinins (lectins), phytoestrogens, oligosaccharides, saponins, and phenolic compounds, which play metabolic roles in humans who frequently consume these foods. Dietary intake of phytochemicals may provide health benefits, protecting against numerous diseases or disorders, such as coronary heart disease, diabetes, high blood pressure and inflammation. The synergistic or antagonistic effects of these phytochemical mixtures from food legumes, their interaction with other components of the diet, and the mechanism of their action have remained a challenge with regard to understanding the role of phytochemicals in health and diseases. Their mitigating effects and the mechanism of their action need to be further addressed if we are to understand the role of phytochemicals in health and diseases. This review provides an overview of the nutritional quality of legumes and their potential contribution in cardiometabolic risk prevention.

The relationship between dietary protein intake and blood pressure: results from the PREMIER study.

Observational and clinical studies suggest that high protein intake, particularly protein from plant sources, might reduce blood pressure (BP). To examine the association of dietary protein with BP, we analysed data from PREMIER, an 18-month clinical trial (n=810) that examined the effects of two multi-component lifestyle modifications on BP. We examined the association of protein intake with BP, and in particular the independent relationship of plant and animal protein with BP. Multivariable linear regression analyses were performed with both cross-sectional and longitudinal data. Dietary plant protein was inversely associated with both systolic and diastolic BP in cross-sectional analyses at the 6-month follow-up (P=0.0045 and 0.0096, respectively). Fruit and vegetable intake was also inversely associated with both systolic and diastolic BP cross-sectionally at 6 months (P=0.0003 and 0.0157, respectively). In longitudinal analyses, a high intake of plant protein at 6 months was marginally associated with a reduction of both systolic and diastolic BP from baseline to 6 months only (P=0.0797 and 0.0866, respectively), independent of change in body weight and waist circumference. Furthermore, increased intake of plant protein, and fruits and vegetables was significantly associated with a lower risk of hypertension at 6 but not at 18 months. Results of this study indicate that plant protein had a beneficial effect on BP and was associated with a lower risk of hypertension at 6 months. Our data, in conjunction with other research, suggest that an increased intake of plant protein may be useful as a means to prevent and treat hypertension.

Weight gain over 5 years in 21,966 meat-eating, fish-eating, vegetarian, and vegan men and women in EPIC-Oxford.

BACKGROUND: Cross-sectional studies have shown that vegetarians and vegans are leaner than omnivores. Longitudinal data on weight gain in these groups are sparse. OBJECTIVE: We investigated changes in weight and body mass index (BMI) over a 5-year period in meat-eating, fish-eating, vegetarian, and vegan men and women in the UK. DESIGN: Self-reported anthropometric, dietary and lifestyle data were collected at baseline in 1994-1999 and at follow-up in 2000-2003; the median duration of follow-up was 5.3 years. SUBJECTS: A total of 21,966 men and women participating in Oxford arm of the European Prospective Investigation into Cancer and Nutrition aged 20-69 years at baseline. RESULTS: The mean annual weight gain was 389 (SD 884) g in men and 398 (SD 892) g in women. The differences between meat-eaters, fish-eaters, vegetarians and vegans in age-adjusted mean BMI at follow-up were similar to those seen at baseline. Multivariable-adjusted mean weight gain was somewhat smaller in vegans (284 g in men and 303 g in women, P<0.05 for both sexes) and fish-eaters (338 g, women only, P<0.001) compared with meat-eaters. Men and women who changed their diet in one or several steps in the direction meat-eater --> fish-eater --> vegetarian --> vegan showed the smallest mean annual weight gain of 242 (95% CI 133-351) and 301 (95% CI 238-365) g, respectively. CONCLUSION: During 5 years follow-up, the mean annual weight gain in a health-conscious cohort in the UK was approximately 400 g. Small differences in weight gain were observed between meat-eaters, fish-eaters, vegetarians and vegans. Lowest weight gain was seen among those who, during follow-up, had changed to a diet containing fewer animal food.

The impact of dietary protein on calcium absorption and kinetic measures of bone turnover in women.

Although high-protein diets induce hypercalciuria in humans, the source of the additional urinary calcium remains unclear. One hypothesis is that the high endogenous acid load of a high-protein diet is partially buffered by bone, leading to increased skeletal resorption and hypercalciuria. We used dual stable calcium isotopes to quantify the effect of a high-protein diet on calcium kinetics in women. The study consisted of 2 wk of a lead-in, well-balanced diet followed by 10 d of an experimental diet containing either moderate (1.0 g/kg) or high (2.1 g/kg) protein. Thirteen healthy women received both levels of protein in random order. Intestinal calcium absorption increased during the high-protein diet in comparison with the moderate (26.2 +/- 1.9% vs. 18.5 +/- 1.6%, P < 0.0001, mean +/- sem) as did urinary calcium (5.23 +/- 0.37 vs. 3.57 +/- 0.35 mmol/d, P < 0.0001, mean +/- sem). The high-protein diet caused a significant reduction in the fraction of urinary calcium of bone origin and a nonsignificant trend toward a reduction in the rate of bone turnover. There were no protein-induced effects on net bone balance. These data directly demonstrate that, at least in the short term, high-protein diets are not detrimental to bone.

Vegetarian diets and childhood obesity prevention.

The increased prevalence of childhood overweight and obesity is not unique to industrialized societies; dramatic increases are occurring in urbanized areas of developing countries. In light of the consensus that obesity is a significant public health concern and that many weight-loss interventions have been unsuccessful in the long term, an exploration of food patterns that are beneficial in the primary prevention of obesity is warranted. The focus of this article is to review the relation between vegetarian diets and obesity, particularly as they relate to childhood obesity. Epidemiologic studies indicate that vegetarian diets are associated with a lower body mass index (BMI) and a lower prevalence of obesity in adults and children. A meta-analysis of adult vegetarian diet studies estimated a reduced weight difference of 7.6 kg for men and 3.3 kg for women, which resulted in a 2-point lower BMI (in kg/m(2)). Similarly, compared with nonvegetarians, vegetarian children are leaner, and their BMI difference becomes greater during adolescence. Studies exploring the risk of overweight and food groups and dietary patterns indicate that a plant-based diet seems to be a sensible approach for the prevention of obesity in children. Plant-based diets are low in energy density and high in complex carbohydrate, fiber, and water, which may increase satiety and resting energy expenditure. Plant-based dietary patterns should be encouraged for optimal health and environmental benefits. Food policies are warranted to support social marketing messages and to reduce the cultural and economic forces that make it difficult to promote plant-based dietary patterns.

Current protein intake in America: analysis of the National Health and Nutrition Examination Survey, 2003-2004.

In recent years there has been considerable interest in the benefits of high-protein diets. This study determined current usual intake of protein in America. Using the most recent data from the National Health and Nutrition Examination Survey, 2003-2004, usual protein intake for Americans aged 2+ years was estimated. Usual protein intake was calculated on a grams per day, grams per kilogram ideal body weight, and a percentage of calories basis. Protein intake averaged 56 +/- 14 g/d in young children, increased to a high of approximately 91 +/- 22 g/d in adults aged 19-30 y, and decreased to approximately 66 +/- 17 g/d in the elderly. The percentage of the male population who consumed less than the estimated average requirement was very low. Our estimates indicated that 7.7% of adolescent females and 7.2-8.6% of older adult women reported consuming protein levels below their estimated average requirement. The median intake of protein on a percentage of calories basis ranged from 13.4% in children aged 4-8 y to 16.0% in men aged 51-70 y. Even the 95th percentile of protein intake did not approach the highest acceptable macronutrient distribution range of 35% for an age/sex group. The highest 95th percentile of protein intake was 20.8% of calories in men aged 51-70 y. Given the demonstrated benefits of higher protein intake on weight management, sarcopenia, and other physiologic functions, efforts should be undertaken to ensure that Americans consume the recommended amount of protein (17-21% of calories as expected from MyPyramid food patterns).

Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Nutrient intake.

A 3-day diary with portion sizes weighed by the subject and a 24-h recall were obtained on 50 sets of subjects: Seventh-day Adventist lacto-ovo-vegetarians and nonvegetarians, and general population nonvegetarians, matched on age (+/- 5 yr), sex, marital status, education, type of milk preferred, and an index of the frequency of dairy and egg product use. An additional 18 unmatched persons who follow a pure vegetarian dietary pattern (use no meat, fish, fowl, dairy, or egg products) were recruited into the study. The rational for the dietary methods used is presented and details of each of the methods used are given. The results of the nutrient analysis of the 24-h recall and 3-day diary are presented. The 3-day nutrient intake means for the four groups are compared to the sex-specific recommended daily allowance both with and without supplements. The contribution of nutritional supplements to the nutrient intake is discussed. All groups show adequate or excess intake levels of calories, protein, and fat when either the 24-h recall or the 3-day diary values are considered. The higher intake of calories noted among nonvegetarians can be explained by a higher intake of both fat and protein in these groups. A, B, and C vitamin levels (3-day dairy estimates) are adequate both with and without supplements. Calcium intake is much below recommended levels for pure vegetarian females. Iron intake is low for all females. A heme iron source does not improve the intake levels for nonvegetarian females. A comparison of these results with prior reports of nutrient intake among Seventh-day Adventists is presented.

Intake of total, animal and plant protein and subsequent changes in weight or waist circumference in European men and women: the Diogenes project.

BACKGROUND: As protein is considered to increase thermogenesis and satiety more than other macronutrients, it may have beneficial effects on prevention of weight gain and weight maintenance. OBJECTIVE: The objective of this study is to assess the association between the amount and type of dietary protein, and subsequent changes in weight and waist circumference (WC). METHODS: 89,432 men and women from five countries participating in European Prospective Investigation into Cancer and Nutrition (EPIC) were followed for a mean of 6.5 years. Associations between the intake of protein or subgroups of protein (from animal and plant sources) and changes in weight (g per year) or WC (cm per year) were investigated using gender and centre-specific multiple regression analyses. Adjustments were made for other baseline dietary factors, baseline anthropometrics, demographic and lifestyle factors and follow-up time. We used random effect meta-analyses to obtain pooled estimates across centres. RESULTS: Higher intake of total protein, and protein from animal sources was associated with subsequent weight gain for both genders, strongest among women, and the association was mainly attributable to protein from red and processed meat and poultry rather than from fish and dairy sources. There was no overall association between intake of plant protein and subsequent changes in weight. No clear overall associations between intakes of total protein or any of the subgroups and changes in WC were present. The associations showed some heterogeneity between centres, but pooling of estimates was still considered justified. CONCLUSION: A high intake of protein was not found associated with lower weight or waist gain in this observational study. In contrast, protein from food items of animal origin, especially meat and poultry, seemed to be positively associated with long-term weight gain. There were no clear associations for waist changes.

Red meat and colon cancer: should we become vegetarians, or can we make meat safer?

The effect of meat consumption on cancer risk is a controversial issue. However, recent meta-analyses show that high consumers of cured meats and red meat are at increased risk of colorectal cancer. This increase is significant but modest (20-30%). Current WCRF-AICR recommendations are to eat no more than 500 g per week of red meat, and to avoid processed meat. Moreover, our studies show that beef meat and cured pork meat promote colon carcinogenesis in rats. The major promoter in meat is heme iron, via N-nitrosation or fat peroxidation. Dietary additives can suppress the toxic effects of heme iron. For instance, promotion of colon carcinogenesis in rats by cooked, nitrite-treated and oxidized high-heme cured meat was suppressed by dietary calcium and by α-tocopherol, and a study in volunteers supported these protective effects in humans. These additives, and others still under study, could provide an acceptable way to prevent colorectal cancer. Copyright © 2011 Elsevier B.V. All rights reserved.

Low protein intake: the impact on calcium and bone homeostasis in humans.

Increasing dietary protein results in an increase in urinary calcium. Despite over 80 y of research, the source of the additional urinary calcium remains unclear. Because most calcium balance studies found little effect of dietary protein on intestinal calcium absorption, it was assumed that the skeleton was the source of the calcium. The hypothesis was that the high endogenous acid load generated by a protein-rich diet would increase bone resorption and skeletal fracture. However, there are no definitive nutrition intervention studies that show a detrimental effect of a high protein diet on the skeleton and the hypothesis remains unproven. Recent studies from our laboratory demonstrate that dietary protein affects intestinal calcium absorption. We conducted a series of short-term nutrition intervention trials in healthy adults where dietary protein was adjusted to either low, medium or high. The highest protein diet resulted in hypercalciuria with no change in serum parathyroid hormone. Surprisingly, within 4 d, the low protein diet induced secondary hyperparathyroidism that persisted for 2 wk. The secondary hyperparathyroidism induced by the low protein diet was attributed to a reduction in intestinal calcium absorption (as assessed by dual stable calcium isotopes). The long-term consequences of these low protein-induced changes in calcium metabolism are not known, but they could be detrimental to skeletal health. Several recent epidemiological studies demonstrate reduced bone density and increased rates of bone loss in individuals habitually consuming low protein diets. Therefore, studies are needed to determine whether low protein intakes directly affect rates of bone resorption, bone formation or both.

Vegetarian diets and blood pressure: a meta-analysis.

IMPORTANCE Previous studies have suggested an association between vegetarian diets and lower blood pressure (BP), but the relationship is not well established. OBJECTIVE To conduct a systematic review and meta-analysis of controlled clinical trials and observational studies that have examined the association between vegetarian diets and BP. DATA SOURCES MEDLINE and Web of Science were searched for articles published in English from 1946 to October 2013 and from 1900 to November 2013, respectively. STUDY SELECTION All studies met the inclusion criteria of the use of (1) participants older than 20 years, (2) vegetarian diets as an exposure or intervention, (3) mean difference in BP as an outcome, and (4) a controlled trial or observational study design. In addition, none met the exclusion criteria of (1) use of twin participants, (2) use of multiple interventions, (3) reporting only categorical BP data, or (4) reliance on case series or case reports. DATA EXTRACTION AND SYNTHESIS Data collected included study design, baseline characteristics of the study population, dietary data, and outcomes. The data were pooled using a random-effects model. MAIN OUTCOMES AND MEASURES Net differences in systolic and diastolic BP associated with the consumption of vegetarian diets were assessed. RESULTS Of the 258 studies identified, 7 clinical trials and 32 observational studies met the inclusion criteria. In the 7 controlled trials (a total of 311 participants; mean age, 44.5 years), consumption of vegetarian diets was associated with a reduction in mean systolic BP (-4.8 mm Hg; 95% CI, -6.6 to -3.1; P < .001; I2 = 0; P = .45 for heterogeneity) and diastolic BP (-2.2 mm Hg; 95% CI, -3.5 to -1.0; P < .001; I2 = 0; P = .43 for heterogeneity) compared with the consumption of omnivorous diets. In the 32 observational studies (a total of 21,604 participants; mean age, 46.6 years), consumption of vegetarian diets was associated with lower mean systolic BP (-6.9 mm Hg; 95% CI, -9.1 to -4.7; P < .001; I2 = 91.4; P < .001 for heterogeneity) and diastolic BP (-4.7 mm Hg; 95% CI, -6.3 to -3.1; P < .001; I2 = 92.6; P < .001 for heterogeneity) compared with the consumption of omnivorous diets. CONCLUSIONS AND RELEVANCE Consumption of vegetarian diets is associated with lower BP. Such diets could be a useful nonpharmacologic means for reducing BP.

Vegetarian and vegan diets in type 2 diabetes management.

Vegetarian and vegan diets offer significant benefits for diabetes management. In observational studies, individuals following vegetarian diets are about half as likely to develop diabetes, compared with non-vegetarians. In clinical trials in individuals with type 2 diabetes, low-fat vegan diets improve glycemic control to a greater extent than conventional diabetes diets. Although this effect is primarily attributable to greater weight loss, evidence also suggests that reduced intake of saturated fats and high-glycemic-index foods, increased intake of dietary fiber and vegetable protein, reduced intramyocellular lipid concentrations, and decreased iron stores mediate the influence of plant-based diets on glycemia. Vegetarian and vegan diets also improve plasma lipid concentrations and have been shown to reverse atherosclerosis progression. In clinical studies, the reported acceptability of vegetarian and vegan diets is comparable to other therapeutic regimens. The presently available literature indicates that vegetarian and vegan diets present potential advantages for the management of type 2 diabetes.

Vegetarian diet affects genes of oxidative metabolism and collagen synthesis.

BACKGROUND/AIM: A vegetarian diet is known to prevent a series of diseases but may influence the balance of carbohydrate and fat metabolism as well as collagen synthesis. This study compares expression patterns of relevant genes in oral mucosa of omnivores and vegetarians. METHODS: Quantitative reverse transcriptase polymerase chain reaction was applied for analysis of mRNA levels from carnitine transporter OCTN2, hepatic CPT1A and nonhepatic CPT1B isoforms of carnitine palmitoyltransferase and collagen (CCOL2A1) in oral mucosa. RESULTS: Compared with volunteers with traditional eating habits, carbohydrate consumption was significantly higher (+22%) in vegetarians. This was associated with a significant stimulation of CPT1A (+50%) and OCTN2 (+10%) and a lowered collagen synthesis (-10%). CONCLUSION: These novel findings provide further insight into the association of a changed fat metabolism and reduced collagen synthesis in vegetarians, which could also play a role in the aging process. Copyright 2008 S. Karger AG, Basel.

Estimated net acid excretion inversely correlates with urine pH in vegans, lacto-ovo vegetarians, and omnivores.

OBJECTIVE: Diet affects urine pH and acid-base balance. Both excess acid/alkaline ash (EAA) and estimated net acid excretion (NAE) calculations have been used to estimate the effects of diet on urine pH. This study's goal was to determine if free-living vegans, lacto-ovo vegetarians, and omnivores have increasingly acidic urine, and to assess the ability of EAA and estimated NAE calculations to predict urine pH. DESIGN: This study used a cross-sectional design. SETTING AND PARTICIPANTS: This study assessed urine samples of 10 vegan, 16 lacto-ovo vegetarian, and 16 healthy omnivorous women in the Boston metropolitan area. Six 3-day food records from each dietary group were analyzed for EAA content and estimated NAE, and correlations with measured urine pH were calculated. RESULTS: The mean (+/- SD) urine pH was 6.15 +/- 0.40 for vegans, 5.90 +/- 0.36 for lacto-ovo vegetarians, and 5.74 +/- 0.21 for omnivores (analysis of variance, P = .013). Calculated EAA values were not significantly different among the three groups, whereas mean estimated NAE values were significantly different: 17.3 +/- 14.5 mEq/day for vegans, 31.3 +/- 8.5 mEq/day for lacto-ovo vegetarians, and 42.6 +/- 13.2 mEq/day for omnivores (analysis of variance, P = .01). The average deattenuated correlation between urine pH and EAA was 0.333; this value was -0.768 for estimated NAE and urine pH, with a regression equation of pH = 6.33 - 0.014 NAE (P = .02, r = -0.54). CONCLUSIONS: Habitual diet and estimated NAE calculations indicate the probable ranking of urine pH by dietary groups, and may be used to determine the likely acid-base status of an individual; EAA calculations were not predictive of urine pH.

Insulin-like growth factor-1 and binding protein-3 in a 2-year soya intervention among premenopausal women.

Soya foods may protect against the development of breast cancer. Insulin-like growth factor (IGF)-1 is under investigation as a possible link between nutrition and cancer. We examined the effect of soya foods on circulating IGF-1 and IGF binding protein (BP)-3 levels among 196 healthy premenopausal women in a 2-year randomised nutritional trial. The intervention group consumed two daily servings of soya foods including tofu, soya milk, soya nuts and soya protein powder (equivalent to 50 mg isoflavones and 5-22 g soya protein per serving); the controls maintained their regular diet. Five serum samples at baseline, 3, 6, 12, and 24 months were collected in the morning during the luteal phase and analysed for IGF-1 and IGFBP-3 by double-antibody ELISA. We applied mixed models to investigate the intervention effect and predictors of serum levels while considering the repeated measurement design. Adherence with the study regimen was high and dropout rates were acceptable. Randomisation resulted in similar mean IGF-1 and IGFBP-3 levels by group. We did not observe a significant intervention effect on IGF-1, IGFBP-3, and their molar ratio during the entire study period. However, urinary isoflavone excretion during the study period was positively associated with IGF-1 (P=0.04) and the IGF-1:IGFBP-3 ratio (P=0.06). The effect was consistent over time. Adding soya foods to the diet of premenopausal women does not appear to lower serum levels of IGF-1 and IGFBP-3; if anything, the greater protein intake from soya may lead to a small increase in IGF-1 serum levels.

Chinese lacto-vegetarian diet exerts favorable effects on metabolic parameters, intima-media thickness, and cardiovascular risks in healthy men.

BACKGROUND: To investigate whether the Chinese lacto-vegetarian diet has protective effects on metabolic and cardiovascular disease (CVD). METHODS: One hundred sixty-nine healthy Chinese lacto-vegetarians and 126 healthy omnivore men aged 21-76 years were enrolled. Anthropometric indexes, lipid profile, insulin sensitivity, pancreatic β cell function, and intima-media thickness (IMT) of carotid arteries were assessed and compared. Cardiovascular risk points and probability of developing CVD in 5-10 years in participants aged 24-55 years were calculated. RESULTS: Compared with omnivores, lacto-vegetarians had remarkably lower body mass index, systolic and diastolic blood pressure, and serum levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, γ-glutamyl transferase, serum creatinine, uric acid, fasting blood glucose, as well as lower total cholesterol/high-density lipoprotein cholesterol ratio. Vegetarians also had higher homeostasis model assessment β cell function and insulin secretion index and thinner carotid IMT than the omnivores did. These results corresponded with lower cardiovascular risk points and probability of developing CVD in 5-10 years in vegetarians 24-55 years old. CONCLUSIONS: In healthy Chinese men, the lacto-vegetarian diet seems to exert protective effects on blood pressure, lipid profiles, and metabolic parameters and results in significantly lower carotid IMT. Lower CVD risks found in vegetarians also reflect the beneficial effect of the Chinese lacto-vegetarian diet.

Attained height of lacto-ovo vegetarian children and adolescents.

The relationship between diet and attained height was studied in children and adolescents in Southern California. Diet pattern was determined from an extensive food frequency questionnaire in 1765 Caucasian children of 7-18 years, attending state schools (452 m and 443 f) and Seventh-day Adventist schools (427 m and 443 f). The major difference in diet pattern between state and Adventist school children was in meat consumption. The Adventist children were split evenly between three categories of frequency in meat consumption (less than 1/week, 1/week-less than 1/d, and greater than or equal to 1/d), while 92 percent of state school children consumed meat daily. Vegetarians (those consuming meat less than 1/week) differed significantly in the consumption of other major food groups, such as fruit and vegetables. All school and diet subgroups were at or above the 50th percentile of the National Center for Health Statistics. Age-adjusted regression analysis showed that on average Adventist vegetarian children were taller than their meat-consuming classmates (2.5 and 2.0 cm for boys and girls, respectively). These results did not change materially when adjusting for other food groups. Nor did adjustment for parental height and socioeconomic factors in a sub-sample of 518 children. The results indicate that vegetarian children and adolescents on a balanced diet grow at least as tall as children who consume meat.

Vitamin B-12 supplementation improves arterial function in vegetarians with subnormal vitamin B-12 status.

OBJECTIVE: Vegetarians are more vascular-healthy but those with subnormal vitamin B-12 status have impaired arterial endothelial function and increased intima-media thickness. We aimed to study the impact of vitamin B-12 supplementation on these markers, in the vegetarians. DESIGN: Double-blind, placebo controlled, randomised crossover study. SETTING: Community dwelling vegetarians. PARTICIPANTS: Fifty healthy vegetarians (vegetarian diet for at least 6 years) were recruited. INTERVENTION: Vitamin B-12 (500 µg/day) or identical placebo were given for 12 weeks with 10 weeks of placebo-washout before crossover (n=43), and then open label vitamin B-12 for additional 24 weeks (n=41). MEASUREMENT: Flow-mediated dilation of brachial artery (FMD) and intima-media thickness (IMT) of carotid artery were measured by ultrasound. RESULTS: The mean age of the subjects was 45±9 years and 22 (44%) were male. Thirty-five subjects (70%) had serum B-12 levels <150 pmol/l. Vitamin B-12 supplementation significantly increased serum vitamin B-12 levels (p<0.0001) and lowered plasma homocysteine (p<0.05). After vitamin B-12 supplementation but not placebo, significant improvement of brachial FMD (6.3±1.8% to 6.9±1.9%; p<0.0001) and in carotid IMT (0.69±0.09 mm to 0.67±0.09 mm, p<0.05) were found, with further improvement in FMD (to 7.4±1.7%; p<0.0001) and IMT (to 0.65±0.09 mm; p<0.001) after 24 weeks open label vitamin B-12. There were no significant changes in blood pressures or lipid profiles. On multivariate analysis, changes in B-12 (β=0.25; p=0.02) but not homocysteine were related to changes in FMD, (R=0.32; F value=3.19; p=0.028). CONCLUSIONS: Vitamin B-12 supplementation improved arterial function in vegetarians with subnormal vitamin B-12 levels, proposing a novel strategy for atherosclerosis prevention.

The effect of a plant-based low-carbohydrate ("Eco-Atkins") diet on body weight and blood lipid concentrations in hyperlipidemic subjects.

BACKGROUND: Low-carbohydrate, high-animal protein diets, which are advocated for weight loss, may not promote the desired reduction in low-density lipoprotein cholesterol (LDL-C) concentration. The effect of exchanging the animal proteins and fats for those of vegetable origin has not been tested. Our objective was to determine the effect on weight loss and LDL-C concentration of a low-carbohydrate diet high in vegetable proteins from gluten, soy, nuts, fruits, vegetables, cereals, and vegetable oils compared with a high-carbohydrate diet based on low-fat dairy and whole grain products. METHODS: A total of 47 overweight hyperlipidemic men and women consumed either (1) a low-carbohydrate (26% of total calories), high-vegetable protein (31% from gluten, soy, nuts, fruit, vegetables, and cereals), and vegetable oil (43%) plant-based diet or (2) a high-carbohydrate lacto-ovo vegetarian diet (58% carbohydrate, 16% protein, and 25% fat) for 4 weeks each in a parallel study design. The study food was provided at 60% of calorie requirements. RESULTS: Of the 47 subjects, 44 (94%) (test, n = 22 [92%]; control, n = 22 [96%]) completed the study. Weight loss was similar for both diets (approximately 4.0 kg). However, reductions in LDL-C concentration and total cholesterol-HDL-C and apolipoprotein B-apolipoprotein AI ratios were greater for the low-carbohydrate compared with the high-carbohydrate diet (-8.1% [P = .002], -8.7% [P = .004], and -9.6% [P = .001], respectively). Reductions in systolic and diastolic blood pressure were also seen (-1.9% [P = .052] and -2.4% [P = .02], respectively). CONCLUSION: A low-carbohydrate plant-based diet has lipid-lowering advantages over a high-carbohydrate, low-fat weight-loss diet in improving heart disease risk factors not seen with conventional low-fat diets with animal products.

Restriction of meat, fish, and poultry in omnivores improves mood: A pilot randomized controlled trial

Background Omnivorous diets are high in arachidonic acid (AA) compared to vegetarian diets. Research shows that high intakes of AA promote changes in brain that can disturb mood. Omnivores who eat fish regularly increase their intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), fats that oppose the negative effects of AA in vivo. In a recent cross-sectional study, omnivores reported significantly worse mood than vegetarians despite higher intakes of EPA and DHA. This study investigated the impact of restricting meat, fish, and poultry on mood. Findings Thirty-nine omnivores were randomly assigned to a control group consuming meat, fish, and poultry daily (OMN); a group consuming fish 3-4 times weekly but avoiding meat and poultry (FISH), or a vegetarian group avoiding meat, fish, and poultry (VEG). At baseline and after two weeks, participants completed a food frequency questionnaire, the Profile of Mood States questionnaire and the Depression Anxiety and Stress Scales. After the diet intervention, VEG participants reduced their EPA, DHA, and AA intakes, while FISH participants increased their EPA and DHA intakes. Mood scores were unchanged for OMN or FISH participants, but several mood scores for VEG participants improved significantly after two weeks. Conclusions Restricting meat, fish, and poultry improved some domains of short-term mood state in modern omnivores. To our knowledge, this is the first trial to examine the impact of restricting meat, fish, and poultry on mood state in omnivores.

Very low n-3 long-chain polyunsaturated fatty acid status in Austrian vegetarians and vegans.

BACKGROUND/AIMS: The objective of the study was to collect data on dietary fat intake of omnivores, vegetarians, vegans and semi-omnivores as well as its impact on n-3 and n-6 fatty acids in long-term markers such as sphingolipids, phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylethanolamine (PE) as well as the calculated sphingo- and phospholipids (SPL) of erythrocytes. METHOD: The present observational study included 98 Austrian adult volunteers of both genders, of which 23 were omnivores, 25 vegetarians, 37 vegans, and 13 semi-omnivores. Information on anthropometry using measured body weight and height was obtained. The amount and composition of ingested fat were calculated from 24-hour recalls and the fatty acid pattern in the phospholipids was assessed using gas chromatography. RESULTS: The unbalanced n-6/n-3 ratio and the limited dietary sources of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in vegans and vegetarians led to reductions in C20:5n-3, C22:5n-3, C22:6n-3 and total n-3 fatty acids in SPL, PC, PS and PE compared with omnivores and semi-omnivores. The total content of polyunsaturated fatty acids, monounsaturated fatty acids and saturated fatty acids remained unchanged. CONCLUSION: The vegetarian diet, with an average n-6/n-3 ratio of 10/1, promotes biochemical n-3 tissue decline. To ensure physical, mental and neurological health vegetarians have to reduce the n-6/n-3 ratio with an additional intake of direct sources of EPA and DHA, regardless of age and gender. (c) 2008 S. Karger AG, Basel.

Effect of protein ingestion on the glucose and insulin response to a standardized oral glucose load.

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 microU X 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 microU X 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.

Mechanisms of twinning: VII. Effect of diet and heredity on the human twinning rate.

OBJECTIVE: To evaluate the possible biochemical effect of diet and heredity on the rates of monozygotic and dizygotic twinning. STUDY DESIGN: In that insulin-like growth factor (IGF) has been found to be elevated in cows selected for their demonstrated increased twinning rate, the effect of agents that influence the level of IGF in women was examined. This was correlated with their prior history of singleton versus twin birthing. In particular, the effect of diets consisting of or excluding animal products that have elevated IGF content (e.g., milk) was considered. RESULTS: Vegan women, who exclude dairy products from their diets, have a twinning rate which is one-fifth that of vegetarians and omnivores. CONCLUSION: The results reported here support the proposed IGF model of dizygotic twinning. Genotypes favoring elevated IGF and diets including dairy products, especially in areas where growth hormone is given to cattle, appear to enhance the chances of multiple pregnancies due to ovarian stimulation.

Changes in laboratory variables in rheumatoid arthritis patients during a trial of fasting and one-year vegetarian diet.

We have previously reported that significant improvement may be obtained in rheumatoid arthritis patients by fasting followed by a vegetarian diet for one year. The present study was carried out to examine to what extent biochemical and immunological variables changed during the clinical trial of fasting and vegetarian diet. For the patients who were randomised to the vegetarian diet there was a significant decrease in platelet count, leukocyte count, calprotectin, total IgG, IgM rheumatoid factor (RF), C3-activation products, and the complement components C3 and C4 after one month of treatment. None of the measured parameters changed significantly during this period in the group of omnivores. The course of 14 of 15 measured variables favored the vegetarians compared with the omnivores, but the difference was only significant for leukocyte count, IgM RF, and the complement components C3 and C4. Most of the laboratory variables declined considerably in the vegetarians who improved according to clinical variables, indicating a substantial reduction in inflammatory activity. The leukocyte count, however, decreased in the vegetarians irrespective of the clinical results. Thus, the decline in leukocyte count may be attributed to vegetarian diet per se and not to the reduction in disease activity. The results of the present study are in accordance with the findings from the clinical trial, namely that dietary treatment can reduce the disease activity in some patients with rheumatoid arthritis.

A maternal vegetarian diet in pregnancy is associated with hypospadias. The ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood.

OBJECTIVE: To investigate the possible role of the maternal diet, particularly vegetarianism and consumption of phytoestrogens, in the origin of hypospadias, which is reported to be increasing in prevalence. SUBJECTS AND METHODS: Detailed information was obtained prospectively from mothers, including previous obstetric history, lifestyle and dietary practices, using structured self-completed questionnaires during pregnancy. Previously recognized associations with environmental and parental factors were examined, focusing particularly on the hypothesized hormonal link. Multivariate logistic regression was used to identify independent associations. RESULTS: Of 7928 boys born to mothers taking part in the Avon Longitudinal Study of Pregnancy and Childhood, 51 hypospadias cases were identified. There were no significant differences in the proportion of hypospadias cases among mothers who smoked, consumed alcohol or for any aspect of their previous reproductive history (including the number of previous pregnancies, number of miscarriages, use of the contraceptive pill, time to conception and age at menarche). Significant differences were detected for some aspects of the maternal diet, i.e. vegetarianism and iron supplementation in the first half of pregnancy. Mothers who were vegetarian in pregnancy had an adjusted odds ratio (OR) of 4.99 (95% confidence interval, CI, 2.10-11.88) of giving birth to a boy with hypospadias, compared with omnivores who did not supplement their diet with iron. Omnivores who supplemented their diet with iron had an adjusted OR of 2.07 (95% CI, 1.00-4.32). The only other statistically significant association for hypospadias was with influenza in the first 3 months of pregnancy (adjusted OR 3.19, 95% CI 1.50-6.78). CONCLUSION: As vegetarians have a greater exposure to phytoestrogens than do omnivores, these results support the possibility that phytoestrogens have a deleterious effect on the developing male reproductive system.

EPIC-Oxford: lifestyle characteristics and nutrient intakes in a cohort of 33 883 meat-eaters and 31 546 non meat-eaters in the UK.

OBJECTIVE: To describe the lifestyle characteristics and nutrient intakes of the Oxford cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC). DESIGN: Cohort of men and women recruited through general practices or by post to include a high proportion of non meat-eaters. Dietary, anthropometric and lifestyle data were collected at baseline and four diet groups were defined. SETTING: United Kingdom. PARTICIPANTS: In total, 65 429 men and women aged 20 to 97 years, comprising 33 883 meat-eaters, 10 110 fish-eaters, 18 840 lacto-ovo vegetarians and 2596 vegans. RESULTS: Nutrient intakes and lifestyle factors differed across the diet groups, with striking differences between meat-eaters and vegans, and fish-eaters and vegetarians usually having intermediate values. Mean fat intake in each diet group was below the UK dietary reference value of 33% of total energy intake. The mean intake of saturated fatty acids in vegans was approximately 5% of energy, less than half the mean intake among meat-eaters (10-11%). Vegans had the highest intakes of fibre, vitamin B1, folate, vitamin C, vitamin E, magnesium and iron, and the lowest intakes of retinol, vitamin B12, vitamin D, calcium and zinc. CONCLUSIONS: The EPIC-Oxford cohort includes 31 546 non meat-eaters and is one of the largest studies of vegetarians in the world. The average nutrient intakes in the whole cohort are close to those currently recommended for good health. Comparisons of the diet groups show wide ranges in the intakes of major nutrients such as saturated fat and dietary fibre. Such variation should increase the ability of the study to detect associations of diet with major cancers and causes of death.

Determinants of hypocholesterolemic response to soy and animal protein-based diets.

The effect of substituting soy for animal protein in mixed diets was determined in young men with mildly elevated plasma cholesterol, 218 to 307 mg/dl. The diets were low in cholesterol, 200 mg/day, with 13 to 16% of energy as protein, 30 to 35% as fat, and a polyunsaturated to saturated fat ratio of 0.5. Of protein 65% was from either mixed animal proteins or isolated soy protein products made comparable by the addition of extracted animal fats. Fresh egg yolk was added to balance the cholesterol content of the diets. Proteins from grains and vegetables were identical in both menus and contributed about 35% of dietary protein. Twenty of 24 subjects decreased plasma cholesterol at the end of the protocol. Subjects were classified as responders or nonresponders as a function of greater or lesser than mean reduction in cholesterol for the groups. Mean decreases in plasma cholesterol, 16 and 13%, for responders in the animal and soy groups were significant, p less than 0.01 and 0.05, respectively. Responders in both groups had higher initial plasma cholesterol values than nonresponders. Although plasma high-density lipoprotein cholesterol decreased slightly, the high-density lipoprotein cholesterol to cholesterol ratio (high-density lipoprotein cholesterol/total cholesterol) remained constant for most individuals. The hypocholesterolemic effects were similar for both animal and soy protein (p less than 0.05) and fat (p less than 0.05) while on the experimental diet. All groups significantly decreased dietary cholesterol (p less than 0.001).

Carrageenans and their use in meat products.

Carrageenans are sulfated linear polysaccharides of D-galactose and 3,6-anhydro-D-galactose extracted from red seaweeds. They have been used by the food industry for their gelling, thickening, and stabilizing properties, and more recently by the meat industry for reduced fat products. Meat is a complex system of muscle tissue, connective tissue, fat, and water; during processing, numerous interactions occur among all these components. These interactions are responsible for the functional properties of the meat system. In meat products, carrageenans contribute to gel formation and water retention. Their addition is of special interest in low-fat meat products because fat reduction often leads to unacceptable, tough textures. When carrageenans are incorporated in these formulations, they improve the textural characteristics of the product by decreasing toughness and increasing juiciness. Although carrageenan interactions with milk proteins have been studied extensively, the mechanism by which carrageenans interact with meat proteins and the other meat components is not fully understood.

[Consequences of exclusive breast-feeding in vegan mother newborn--case report].

We report on the case of an infant who was hospitalized because of failure to thrive, megaloblastic anemia, and delayed psychomotor development. He was 10 months old and had been exclusively breast-fed by his vegan mother. Investigations showed vitamin B(12) deficiency with hematocytopenia and pervasive developmental disorders as well as vitamin K and vitamin D deficiencies. The infant's mother presented the same deficiencies. Introduction of vitamin supplementation normalized the biological disorders, and the infant showed weight gain and neurological improvement. This case highlights that a vegan diet during pregnancy followed by exclusive breast-feeding can induce nutritional deficiencies in the newborn, with clinical consequences. Detecting mother and child vitamin deficiencies and preventing them is essential.

Biomonitoring of Carcinogenic Heterocyclic Aromatic Amines in Hair: A Validation Study

A facile method was established to measure heterocyclic aromatic amines (HAAs) accumulated in human hair and rodent fur. The samples were digested by base hydrolysis, and the liberated HAAs were isolated by tandem solvent/solid-phase extraction. Quantification was done by liquid chromatography/tandem mass spectrometry, using a triple stage quadrupole mass spectrometer in the selected reaction monitoring mode. In a pilot study of 12 human volunteers, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was detected in hair of six meat-eaters at levels ranging from 290 to 890 pg/g hair. 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-9H-pyrido[2,3-b]indole (AαC) were below the limit of quantification (LOQ) (50 pg/g hair) in hair from meat-eaters and six vegetarians. PhIP was detected in the hair from one vegetarian, and at level just above the LOQ (65 pg/g hair), indicating PhIP exposure occurs primarily through meat consumption. The levels of PhIP in hair samples from two meat-eaters varied by less than 24% over a 6-month interval, signifying that the exposure to PhIP and its accumulation in hair are relatively constant over time. In a controlled feeding study, female C57BL/6 mice were given these HAAs in their drinking water for 1 month, at six daily dose concentrations ranging from 0, 0.080 to 800 µg/kg body weight. PhIP was detected in fur of mice at all doses, whereas AαC and MeIQx were detected in fur at dosages ≥0.8 µg AαC/kg body weight and ≥8 µg MeIQx/kg body weight. There was a strong positive relationship between dosage and each of the HAAs accumulated in fur and their DNA adducts formed in liver and colon (p-values <0.0001); however, the levels of HAA in fur did not correlate to the levels of DNA adducts after adjustment of dose. Thus, hair appears to be a promising long-lived biomarker with by which we can assess the exposure to PhIP, a potential human carcinogen.

Relevance of protein fermentation to gut health.

It is generally accepted that carbohydrate fermentation results in beneficial effects for the host because of the generation of short chain fatty acids, whereas protein fermentation is considered detrimental for the host's health. Protein fermentation mainly occurs in the distal colon, when carbohydrates get depleted and results in the production of potentially toxic metabolites such as ammonia, amines, phenols and sulfides. However, the effectivity of these metabolites has been established mainly in in vitro studies. In addition, some important bowel diseases such as colorectal cancer (CRC) and ulcerative colitis appear most often in the distal colon, which is the primary site of protein fermentation. Finally, epidemiological studies revealed that diets rich in meat are associated with the prevalence of CRC, as is the case in Western society. Importantly, meat intake not only increases fermentation of proteins but also induces increased intake of fat, heme and heterocyclic amines, which may also play a role in the development of CRC. Despite these indications, the relationship between gut health and protein fermentation has not been thoroughly investigated. In this review, the existing evidence about the potential toxicity of protein fermentation from in vitro animal and human studies will be summarized. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nutrient based estimation of acid-base balance in vegetarians and non-vegetarians.

A first objective of the present study was to estimate the acid-base balance of the food intake in vegetarians and non-vegetarians. A second objective was to evaluate if additional input of specific food items on the existing potential renal acid load (PRAL) list was necessary for the comparison of the two dietary patterns. Thirty vegetarians between the age of 18 and 30 years were matched for sex, age and BMI with 30 non-vegetarians. Based on the 3-days food diaries the acid-base status of the food intake was estimated using the PRAL method. Mean PRAL values as estimated with the standard table yielded an alkaline load of -5.4 +/- 14.4 mEq/d in the vegetarians compared to an acid load of 10.3 +/- 14.4 mEq/d in the nonvegetarians (p<0.001). Mean PRAL values as estimated with the extended table yielded an alkaline load of -10.9 +/-19.7 mEq/d in the vegetarians compared to an acid load of 13.8 +/- 17.1 mEq/d for the non-vegetarians (p<0.001). The findings of this study indicate that vegetarian food intake produces more alkaline outcomes compared to non-vegetarian diets. The use of the standard PRAL table was sufficient for discrimination between the two diets.

Meats, processed meats, obesity, weight gain and occurrence of diabetes among adults: findings from Adventist Health Studies.

AIM: To examine the relation between meat intake and diabetes occurrence in adults. METHODS: In a prospective cohort study we examined the relation between diet and incident diabetes recorded among 8,401 cohort members (ages 45-88 years) of the Adventist Mortality Study and Adventist Health Study (California, USA) who were non-diabetic at baseline. During the 17-year follow-up, we identified 543 incident diabetes cases. RESULTS: (1) Subjects who were weekly consumers of all meats were 29% (OR = 1.29; 95% CI 1.08, 1.55) more likely (relative to zero meat intake) to develop diabetes. (2) Subjects who consumed any processed meats (salted fish and frankfurters) were 38% (OR = 1.38; 95% CI 1.05-1.82) more likely to develop diabetes. (3) Long-term adherence (over a 17-year interval) to a diet that included at least weekly meat intake was associated with a 74% increase (OR = 1.74; 95% CI 1.36-2.22) in odds of diabetes relative to long-term adherence to a vegetarian diet (zero meat intake). Further analyses indicated that some of this risk may be attributable to obesity and/or weight gain--both of which were strong risk factors in this cohort. It is noteworthy that even after control for weight and weight change, weekly meat intake remained an important risk factor (OR = 1.38; 95% CI 1.06-1.68) for diabetes [corrected]. CONCLUSIONS: Our findings raise the possibility that meat intake, particularly processed meats, is a dietary risk factor for diabetes. 2008 S. Karger AG, Basel.

Diet, lifestyle, and the etiology of coronary artery disease: the Cornell China study.

Investigators collected and analyzed mortality data for >50 diseases, including 7 different cancers, from 65 counties and 130 villages in rural mainland China. Blood, urine, food samples, and detailed dietary data were collected from 50 adults in each village and analyzed for a variety of nutritional, viral, hormonal, and toxic chemical factors. In rural China, fat intake was less than half that in the United States, and fiber intake was 3 times higher. Animal protein intake was very low, only about 10% of the US intake. Mean serum total cholesterol was 127 mg/dL in rural China versus 203 mg/dL for adults aged 20-74 years in the United States. Coronary artery disease mortality was 16.7-fold greater for US men and 5.6-fold greater for US women than for their Chinese counterparts. The combined coronary artery disease mortality rates for both genders in rural China were inversely associated with the frequency of intake of green vegetables and plasma erythrocyte monounsaturated fatty acids, but positively associated with a combined index of salt intake plus urinary sodium and plasma apolipoprotein B. These apolipoproteins, in turn, are positively associated with animal protein intake and the frequency of meat intake and inversely associated with plant protein, legume, and light-colored vegetable intake. Rates of other diseases were also correlated with dietary factors. There was no evidence of a threshold beyond which further benefits did not accrue with increasing proportions of plant-based foods in the diet.

The effect of vegetarian diet on selected essential nutrients in children.

INTRODUCTION: Vegetarian diets are considered to promote health and reduce the risk of some chronic diseases. It is also known that restriction or exclusion of animal foods may result in low intake of essential nutrients. The aim of the presented study was to assess the intake and serum status of vitamin B12, folate, vitamins A, E and D, as well as concentrations of homocysteine, total antioxidant status and iron balance in Polish vegetarian children. MATERIAL AND METHODS: The study included 50 children, aged 5-11 who had been referred to the Institute of Mother and Child for dietary consultation. From those, 32 were vegetarians (aged 6.5±4.2 years) and 18 omnivores (aged 7.9±2.7 years). Dietary constituents were analyzed using the nutritional programme Dietetyk2®. Folate and vitamin B12 were determined with a chemiluminescence immunoassay, total homocysteine with a fluorescence polarization immunoassay and TAS (total antioxidant status) by colorimetric method. Vitamin A and E in serum were determined by the high-pressure liquid chromatography method (HPLC) and vitamin D by immunoenzymatic assay (ELISA). Concentrations of iron, ferritin, transferrin and total iron-binding capacity (TIBC) in serum were determined by commercially available kits. RESULTS: In vegetarian children daily intake of vitamin B12 (1.6 ěg) was in the recommended range, that of folate (195 ěg) and vitamin A (1245 ěg) higher, but vitamin E slightly lower (6.6 ěg) and three-fold lower vitamin D (1.1 ěg) than references allowance. Serum concentrations of vitamin B12 (548 pg/ml), folate (12.8 ng/ml), vitamin A (1.2 ěmol/L), vitamin E (15.6 ěmol/l) were within physiological range, but that of vitamin D (13.7 ěg/L) was only half of the lowest limit of the reference value. In vegetarian children in comparison to omnivorous similar levels of homocysteine (6.13 ěmol/L vs 5.45 ěmol/L) and vitamin A (1,17 ěmol/L vs 1.32 ěmol/L) were observed. Lower (p<0.05) values of vitamin E (15.6 ěmol/L vs 18.4 ěmol/L) and TAS (1.21 mmol/L vs 1.30 mmol/L; p<0.0001) were found. Concentrations of iron markers were in physiological range. CONCLUSION: Obtained results indicated that intakes of vitamin B12 and folic acid from vegetarian diets are sufficient to maintain serum concentrations of both homocysteine and iron in the range observed in omnivorous children. High consumption of vitamin A and low vitamin E only slightly affected their serum values. Significantly lower concentration of serum vitamin E in vegetarian children in comparison to nonvegetarians may be reflected with statistically significant lowering of total antioxidant status. Insufficient intake of vitamin D and its low serum concentration should be under close monitoring in vegetarian children. In order to prevent vitamin D deficiency appropriate age-dependent supplementation should be considered.

Cancer incidence in British vegetarians

Background: Few prospective studies have examined cancer incidence among vegetarians. Methods: We studied 61 566 British men and women, comprising 32 403 meat eaters, 8562 non-meat eaters who did eat fish (‘fish eaters') and 20 601 vegetarians. After an average follow-up of 12.2 years, there were 3350 incident cancers of which 2204 were among meat eaters, 317 among fish eaters and 829 among vegetarians. Relative risks (RRs) were estimated by Cox regression, stratified by sex and recruitment protocol and adjusted for age, smoking, alcohol, body mass index, physical activity level and, for women only, parity and oral contraceptive use. Results: There was significant heterogeneity in cancer risk between groups for the following four cancer sites: stomach cancer, RRs (compared with meat eaters) of 0.29 (95% CI: 0.07–1.20) in fish eaters and 0.36 (0.16–0.78) in vegetarians, P for heterogeneity=0.007; ovarian cancer, RRs of 0.37 (0.18–0.77) in fish eaters and 0.69 (0.45–1.07) in vegetarians, P for heterogeneity=0.007; bladder cancer, RRs of 0.81 (0.36–1.81) in fish eaters and 0.47 (0.25–0.89) in vegetarians, P for heterogeneity=0.05; and cancers of the lymphatic and haematopoietic tissues, RRs of 0.85 (0.56–1.29) in fish eaters and 0.55 (0.39–0.78) in vegetarians, P for heterogeneity=0.002. The RRs for all malignant neoplasms were 0.82 (0.73–0.93) in fish eaters and 0.88 (0.81–0.96) in vegetarians (P for heterogeneity=0.001). Conclusion: The incidence of some cancers may be lower in fish eaters and vegetarians than in meat eaters.

Lignans and isoflavonoids in plasma and prostatic fluid in men: samples from Portugal, Hong Kong, and the United Kingdom.

BACKGROUND: Chinese men have lower incidences of prostate cancer compared to men from Europe and North America. Asians consume large quantities of soya, a rich source of isoflavanoids phyto-oestrogens and have high plasma and urinary levels of these compounds. The mammalian lignans, enterolactone and enterodiol, are another group of weak plant oestrogens and are derived from seeds, cereals and grains. Vegetarians have high plasma and urinary concentrations of lignans. METHODS: The concentrations lignans and isoflavonic phyto-oestrogens were determined by gas chromatography-mass spectrometry (GC-MS) in plasma and prostatic fluid from Portuguese, Chinese and British men consuming their traditional diets. RESULTS: In prostatic fluid the mean concentrations of enterolactone were 31, 162 and 20.3 ng/ml for Hong Kong, Portugal and Britain respectively. Very high levels of enterolactone (> 600 ng/ml) were observed in the prostatic fluid of some of the men from Portugal. High concentrations of equol (3270 ng/ml) and daidzein (532 ng/ml) were found in a sample of prostatic fluid from Hong Kong. Higher mean levels of daidzein were observed in prostatic fluid from Hong Kong at 70 ng/ml, compared to 4.6 and 11.3 ng/ml in samples from Portugal and Britain respectively. Mean levels of daidzein were higher in the plasma samples from Hong Kong (31.3 ng/ml) compared to those from Portugal (1.3 ng/ml) and Britain (8.2 ng/ml). In general, the mean plasma concentrations of enterolactone from the three centres were similar, at 6.2, 3.9 and 3.9 ng/ml in samples from Hong Kong Portugal and Britain respectively. CONCLUSIONS: Higher concentrations of the isoflavanoid phyto-oestrogens, daidzein and equol, were found in the plasma and prostatic fluid of men from Hong Kong compared to those from Britain and Portugal. However, the levels of the lignan, enterolactone, were very much higher in prostatic fluid of Portuguese men. Isoflavanoids and lignans have many interesting properties and may, in part, be responsible for lower incidences of prostate cancer in men from Asia and also some Mediterranean countries. The isoflavanoids from soya, which are present in high concentrations in the prostatic fluid of Asian men, may be protective against prostate disease.

Excess dietary protein can adversely affect bone.

The average American diet, which is high in protein and low in fruits and vegetables, generates a large amount of acid, mainly as sulfates and phosphates. The kidneys respond to this dietary acid challenge with net acid excretion, as well as ammonium and titratable acid excretion. Concurrently, the skeleton supplies buffer by active resorption of bone. Indeed, calciuria is directly related to net acid excretion. Different food proteins differ greatly in their potential acid load, and therefore in their acidogenic effect. A diet high in acid-ash proteins causes excessive calcium loss because of its acidogenic content. The addition of exogenous buffers, as chemical salts or as fruits and vegetables, to a high protein diet results in a less acid urine, a reduction in net acid excretion, reduced ammonium and titratable acid excretion, and decreased calciuria. Bone resorption may be halted, and bone accretion may actually occur. Alkali buffers, whether chemical salts or dietary fruits and vegetables high in potassium, reverse acid-induced obligatory urinary calcium loss. We conclude that excessive dietary protein from foods with high potential renal acid load adversely affects bone, unless buffered by the consumption of alkali-rich foods or supplements.