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Background/aims: The impact of vitamin B status on cognitive functioning in Alzheimer's disease (AD) is disputed. Using a population-based sample, we examined the associations of vitamin B(12) and folate with cognitive functioning in clinical (n = 44) and preclinical (n = 39) AD., Methods: The groups were subdivided in terms of low (<200 pmol/l) versus normal levels of B(12) and low (<13 nmol/l) versus normal folate levels. Participants were administered tests of verbal and nonverbal episodic memory, visuospatial abilities and verbal fluency., Results: As expected, the preclinical AD group performed better than the AD group across most cognitive tests. More interestingly, the effects of low vitamin B(12) and folate levels were negligible across all cognitive tests in clinical and preclinical AD., Conclusion: These findings suggest that the influence of vitamin B deficiency on cognitive functioning is overshadowed by the neurodegenerative processes associated with AD., ((c) 2007 S. Karger AG, Basel.)

Background: A vegetarian diet is considered to promote health and longevity and reduce the risk of cardiovascular diseases and cancer. However, a vegetarian diet may be deficient in some nutrients. Exclusion of animal products in vegetarian diets may affect the status of certain B-vitamins, and further cause the rise of plasma homocysteine concentration., Objective: The nutritional status of various B-vitamins (B(1), B(2), B(6), B(12), folic acid) and the concentration of homocysteine in blood plasma of omnivores (n = 40), vegetarians (n = 36) and vegans (n = 42) in Austria was evaluated., Methods: The evaluation was done using the functional parameters erythrocyte transketolase (ETK), glutathione reductase (EGR) and glutamic oxaloacetic transaminase (EGOT) activation coefficients. Enzyme activity was measured photometrically. The quantity of vitamins B(1), B(2) and B(6) in urine and the concentrations of vitamin B(6) and homocysteine in plasma were determined by HPLC methods with fluorescence detection. Plasma concentration of vitamin B(12) and folic acid were measured with radioimmunoassay., Results: Most of the subjects showed a satisfying vitamin B(1) status. Vegans presented a significantly lower mean plasma vitamin B(12) concentration than omnivores and vegetarians and deficiency in 2.4% of the volunteers but the highest mean value of plasma folate among the investigated groups. A deficient status of folate was found in 18% of omnivores and in approximately 10% of vegans and vegetarians. The status of riboflavin is considered to be deficient in about 10% of omnivores and vegetarians and in over 30% of vegans. According to the activation coefficient of GOT, approximately one third of all subjects showed vitamin B(6) deficiency. Elevated homocysteine concentration in plasma was observed in 66% of the vegans and about 45-50% of the omnivores and vegetarians. Vegan subjects had significantly higher mean plasma homocysteine levels than omnivores., Conclusion: Thiamin and folate need not be a problem in a well-planned vegan diet. Vitamins B(12) and B(2) may need attention in the strict vegan diet, especially regarding elevated homocysteine levels in plasma. Pyridoxine status appeared to be independent of the diet., (Copyright 2006 S. Karger AG, Basel.)

The daily intake of vitamin B1, B2, B6, PP, C, A, D and E was investigated in 297 adult subjects, undergoing a check-up examination in a Health Center in Burgundy, by the 7-day self-recorded prospective protocol, to determine the prevalence of vitamin deficiency risks in an area of a West European Country. The daily vitamin intake was lower than the French Recommended Dietary Allowances: RDA (CNERNA, 1981). The intake was between 50 and 80% of RDA for vitamin B1 in 58%, B2 in 24%, B6 in 59%, PP in 43%, C in 21%, A in 8%, D in 0.6%, E in 53% of the female population and for B1 in 40%, B2 in 18.5%, B6 in 59%, PP in 46%, C in 27%, A in 11%, D in 7% and E in 47% of the male population. The daily vitamin intake was less than half of RDA vor vitamin B1 in 11%, B2 in 0.6%, B6 in 33%, PP in 6.3%, C in 4.5%, A in 0.6%, D in 98%, E in 36% in the females and for B1 in 3%, B6 in 8.5%, PP in 3.5%, C in 5%, A in 0.7%, D in 91% and E in 9% in the males. The use of a probability analysis for estimating vitamin deficiencies showed intakes below their own requirement in 37.8% for B1, 18% for B2, 58.6% for B6, 46% for PP, 29% for C, 8.3% for A, 98% for D and 43.4% for E in the males and 62.5% for B1, 20.9% for B2, 86% for B6, 46% for PP, 24% for C, 9.2% for A, 98% for D and 59.7% for E in the females. Significant correlations were found between the daily vitamin intake and the caloric intake for B1 (r = 0.64), B2 (r = 0.46), B6 (r = 0.64) and PP (r = 0.62). The significantly lower caloric intake in females than in males explains a higher proportion of vitamin deficiencies for B1, B2, B6 and PP in this population. The consumption of green vegetables and fresh fruit, and, consequently, vitamin C intake, was higher in females. Although it was not possible to determine to what extent the vitamin intake deficiency contributes to an impaired biochemical vitamin status, the dietary data of this study supply sufficient information to demonstrate high prevalences of deficient vitamin status in France, particularly for B1, B6 and E.