The trace metal status of a group of post-menopausal vegetarians

Manganese-induced hyperactivity and dopaminergic dysfunction depend on age, sex and YAC128 genotype

Manganese (Mn) is an essential micronutrient but is neurotoxic in excess. Environmental and genetic factors influence vulnerability to Mn toxicity, including sex, age, and the autosomal dominant mutation that causes Huntington disease (HD). To better understand the differential effects of Mn in wild-type (WT) versus YAC128 mice, we examined impacts of Mn exposure across different ages and sexes on disease-relevant behavioral tasks and dopamine dynamics. Young (3-week) and aged (12-month) WT and YAC128 mice received control (70 ppm) or high (2400 ppm) Mn diet for 8 weeks followed by a battery of behavioral tasks. In young female WT mice, high Mn diet induced hyperactivity across two independent behavioral tasks. Changes in the expression of tyrosine hydroxylase (TH) were consistent with the behavioral data in young females such that elevated TH in YAC128 on control diet was decreased by high Mn diet. Aged YAC128 mice showed the expected disease-relevant behavioral impairments in females and decreased TH expression, but we observed no significant effects of Mn diet in either genotype of the aged group. Fast-scan cyclic voltammetry recorded dopamine release and clearance in the nucleus accumbens of eight-month-old WT and YAC128 mice following acute Mn exposure (3×/1 week subcutaneous injections of 50 mg/kg MnCl[2]-tetrahydrate or saline). In WT mice, Mn exposure led to faster dopamine clearance that resembled saline treated YAC128 mice. Mn treatment increased dopamine release only in YAC128 mice, possibly indirectly correcting the faster dopamine clearance observed in saline treated YAC128 mice. The same exposure paradigm led to decreased dopamine and serotonin and metabolites (3-MT, HVA and 5-HIAA) in striatum and increased glutamate in YAC128 mice but not WT mice. These studies confirm an adverse effect of Mn in young, female WT animals and support a role for Mn exposure in stabilizing dopaminergic dysfunction and motivated behavior in early HD.

Dietary Manganese Exposure in the Adult Population in Germany-What Does it Mean in Relation to Health Risks?

Manganese is both an essential nutrient and a potential neurotoxicant. Therefore, the question arises whether the dietary manganese intake in the German population is on the low or high side. Results from a pilot total diet study in Germany presented here reveal that the average dietary manganese intake in the general population in Germany aged 14-80 years is about 2.8 mg day^-1 for a person of 70 kg body weight. This exposure level is within the intake range of 2-5 mg per person and day as recommended by the societies for nutrition in Germany, Austria, and Switzerland. No information on the dietary exposure of children in Germany can be provided so far. Although reliable information on health effects related to oral manganese exposure is limited, there is no indication from the literature that these dietary intake levels are associated with adverse health effects either by manganese deficiency or excess. However, there is limited evidence that manganese taken up as a highly bioavailable bolus, for example, uptake via drinking water or food supplements, could pose a potential risk to human health-particularly in certain subpopulations-when certain intake amounts, which are currently not well defined, are exceeded.

Effect of vegetarian diets on zinc status: a systematic review and meta-analysis of studies in humans

Plant-based diets contain less saturated fat and cholesterol and more folate, fibre and phytochemicals than omnivorous diets, but some micronutrients, especially zinc, are poorly bioavailable. The findings of studies exploring the zinc intake and zinc status in populations that habitually consume vegetarian diets are inconsistent. This study aims to investigate the effects of plant-based diets on dietary zinc intake and status in humans using systematic review and meta-analysis techniques. Thirty-four studies were included in the systematic review. Of these, 26 studies (reporting 48 comparisons) compared males and/or females consuming vegetarian diets with non-vegetarian groups and were included in meta-analyses. Dietary zinc intakes and serum zinc concentrations were significantly lower (-0.88 ± 0.15 mg day(-1), P < 0.001 and -0.93 ± 0.27 µmol L(-1), P = 0.001 respectively; mean ± standard error) in populations that followed habitual vegetarian diets compared with non-vegetarians. Secondary analyses showed greater impact of vegetarian diets on the zinc intake and status of females, vegetarians from developing countries and vegans. Populations that habitually consume vegetarian diets have low zinc intakes and status. Not all vegetarian categories impact zinc status to the same extent, but a lack of consistency in defining vegetarian diets for research purposes makes dietary assessment difficult. Dietary practices that increase zinc bioavailability, the consumption of foods fortified with zinc or low-dose supplementation are strategies that should be considered for improving the zinc status of vegetarians with low zinc intakes or serum zinc concentrations at the lower end of the reference range.

Apparent copper absorption from a vegetarian diet

BACKGROUND

Vegetarian diets often contain more copper than do nonvegetarian diets, but observations of decreased plasma copper associated with vegetarian diets suggest that these diets have lower copper bioavailability than do nonvegetarian diets.

OBJECTIVE

Our objective was to determine apparent copper absorption from controlled lactoovovegetarian and nonvegetarian diets.

DESIGN

Eighteen women aged 20-43 y consumed lactoovovegetarian and nonvegetarian weighed diets for 8 wk each in a randomized, crossover design. The lactoovovegetarian and nonvegetarian diets provided 1.45 and 0.94 mg Cu, 38 and 16 g dietary fiber, and 1584 and 518 mg phytic acid, respectively, per 9.2 MJ (2200 kcal). After the women had been consuming each diet for 4 wk, their apparent copper absorption was determined by measuring the fecal excretion of the 65Cu stable isotope, extrinsically added to the entire menu as 65CuCl2.

RESULTS

Plasma copper and ceruloplasmin were not affected by diet. The efficiency of apparent copper absorption from the lactoovovegetarian diet was less (33%) than that from the nonvegetarian diet (42%) (pooled SD: 9%; P < 0.05). However, because the lactoovovegetarian diet contained approximately 50% more copper, the total apparent copper absorption from the lactoovovegetarian diet (0.48 mg/d) was greater than that from the nonvegetarian diet (0.40 mg/d) (pooled SD: 0.09 mg; P < 0.05).

CONCLUSION

Although copper was less efficiently absorbed from a vegetarian diet than from a nonvegetarian diet, total apparent copper absorption was greater from the vegetarian diet because of its greater copper content.

Daily dietary intake of chromium in southern Spain measured with duplicate diet sampling

We measured daily dietary Cr intake in southern Spain by sampling duplicate diets for seven consecutive days in different population groups. Cr was determined by electrothermal atomization-atomic absorption spectrometry. The samples were mineralized in a digestion block with HNO(3), HClO(4) and V(2)O(5). A total of 161 duplicate diets from twenty-three subjects were analysed, and mean levels of Cr intake ranged from 9.39 to 205.16 microg/d. Mean Cr intake (100 microg/d) was similar to levels found for most other countries, and was within the range recommended by the National Research Council for a safe and adequate daily intake (50-200 microg/d). Chromium intake correlated significantly with energy, protein and carbohydrate intake, and with the daily intake of Zn, Fe, Mg, K, Na, Ca and nicotinic acid in the diets analysed.

Daily dietary intake of manganese by several population groups in Belgium: preliminary reports

Atomic absorption spectrometry is used to determine manganese content of several duplicate meals consumed by different population groups in the Antwerp region (Belgium). Daily elemental intake, beverages not included, is calculated and proven to be within the recommended daily allowances (National Academy of Sciences, USA) except for a higher intake by macrobiotics (6.7 +/- 3.8 mg per day). Intake level of vegetarians is similar to that of omnivorous adults, 2.9 +/- 2.0 and 2.5 +/- 0.3 mg per day, respectively. Values obtained in this study are compared with scarce data on intake by similar groups in other countries.

Daily dietary intake of copper, zinc and selenium by different population groups in Burundi, Africa

Daily dietary intake of copper, zinc and selenium for different population groups in Burundi, Africa, has been determined, using different sampling strategies, by atomic absorption spectrometry. Recommended daily intakes (RDA, National Academy, USA) are met for copper and zinc. For selenium, especially the rural population risk a deficiency as observed with a daily intake of 17 micrograms. The importance of different types of food in daily intake is discussed. Legumes proved to be an important source of copper, while for selenium fish contributes in a large part in dietary intake. Calculated total daily intakes are compared with intakes recently published for other countries.

Protein intake and urinary excretion of protein-derived metabolites in aging female vegetarians and nonvegetarians

Relationships among age, protein intake, and urinary excretion of protein-derived metabolites were studied in 125 vegetarian and nonvegetarian women ages 40-92. There were 63 women in the vegetarian (AV) group and 62 women in the nonvegetarian (NV) group. Average daily intakes of energy and total animal and vegetable protein were calculated from 7-day dietary records. Twenty-four-hour urine samples were analyzed for total nitrogen, urea, creatinine, hydroxyproline, and inorganic sulfate. Energy intakes for the two groups were similar. AVs consumed less total and animal protein and more vegetable protein than NVs, even though both groups consumed more than the RDA for protein. No significant differences existed between the groups in the urinary excretion of total nitrogen, urea nitrogen, hydroxyproline, or inorganic sulfate. Energy and protein intakes and total nitrogen excretion were lower in older AVs than in younger AVs, while those of NVs increased between 40 and 55 years of age, and decreased among the older NV women. The relationship between these variables and age in NVs was more accurately described by polynomial rather than linear regression models.

Long-term effects of a vegetarian diet on the nutritional status of elderly people (Dutch Nutrition Surveillance System)

The health and nutritional status (anthropometry, and blood and urine biochemistry) of 44 Dutch apparently healthy vegetarians, aged 65-97 years, refraining from meat, fish, and poultry consumption, was assessed for insight into long-term consequences of ovo-lacto- or lacto-vegetarianism. The results indicate that in comparison to omnivorous elderly the vegetarian elderly (especially men) have aged successfully with respect to cardiovascular risk factors. In contrast, vegetarian elderly are at a higher risk for a marginal iron, zinc, and vitamin B12 status. Although several vegetarian elderly showed low levels of 25-hydroxyvitamin D in plasma and many had low values of 24-hr urine volume (per kg body weight), these values are not likely the result of a vegetarian diet per se. It is concluded that, although some nutrition-related risks are prevalent among vegetarian elderly, these risks can probably be prevented by lifestyle changes.

Adequacy of a vegetarian diet at old age (Dutch Nutrition Surveillance System)

To assess the adequacy of a vegetarian diet at old age, the dietary intake (assessed through dietary history with cross-check) of 44 apparently healthy lacto-(ovo-)vegetarians, aged 65-97 years, was evaluated. Adequacy was assessed by a comparison of nutrient intake with (Dutch) recommendations and by evaluating data on nutritional status. The results were also compared with data of elderly omnivores. In contrast to elderly omnivores, percentages of energy from protein (13%), fat (37%), and carbohydrates (50%) as well as P/S ratio (0.63) were close to or within the range of Dutch guidelines regarding a healthy diet (percentages of energy from protein, fat, and carbohydrates 10-15, 30-35, and 55%, respectively: P/S ratio 0.5-1.0). For most of the micronutrients studied intake was adequate, and nutrient density of the vegetarian diet was higher than of the omnivorous diet. However, the supply of zinc (average daily intake 8.5 and 7.6 mg for men and women, respectively), iron (because of lower bioavailability of nonheme iron), vitamin B12 (women only: intake 2.3 micrograms/day), and water (daily intake less than 1600 ml for 30% of the vegetarians) need special attention, considering the relatively high prevalence of a marginal status of these nutrients. In conclusion, a lacto-(ovo-)vegetarian diet can be adequate at old age, provided that it is carefully planned, especially with respect to the supply of iron, zinc, and vitamin B12.

The effect of income on selenium intake and status in Utah County, Utah

Foodstuffs produced and/or purchased locally were analyzed for Se. The effect of income and gender on Se intake and status of Utah County residents was evaluated by measurement of the following indicators: erythrocyte (RBC) and plasma Se concentration, and activity of Se-glutathione peroxidase (Se-GSH-Px) (EC 1.11.1.9) in RBCs, platelets, and plasma. A Random Digit Dialing procedure was employed to stratify subjects according to gender and annual family income (less than +10,000, +10,000-20,000, greater than +20,000) in a 2 x 3 factorial design, seven subjects per cell. The weekly consumption of 44 foods shown to contribute over 90% of the Se intake of U.S. subjects was recorded for each study participant. The estimated minimum daily intake for this sample was 76.0 +/- 4.5 micrograms Se/day (mean +/- SEM). Available grain products are not produced locally, and their Se content is lower than average values reported by the U.S.D.A. Locally produced meat and dairy products had higher than average Se contents. In spite of lower grain Se and higher meat Se concentrations, subjects in this study derived more Se from grain and dairy products, and less from meat products than did subjects in a nationwide sample. The Se status of Utah County residents is similar to several other populations in the United States. There were no significant differences in Se status or intake due to gender or income. The results suggest that consumption of other foods produced in a "high Se" area can maintain Se intake and status in spite of reduced consumption of meat products generally viewed as more reliable sources of dietary Se.