Effects of homocysteine lowering with B vitamins on cognitive aging: meta-analysis of 11 trials with cognitive data on 22,000 individuals
Clarke R
Published in The American Journal of Clinical Nutrition
Methodology
Meta-analysis by the B-Vitamin Treatment Trialists Collaboration of individual data from 11 randomised placebo-controlled trials of homocysteine-lowering B vitamins; domain-based z scores for memory, speed and executive function plus global cognitive function.
Key Findings
This collaborative meta-analysis combined 11 large randomised trials with cognitive data on 22,000 participants: four trials with domain-based z scores before and after a mean 2.3 years of treatment (1340 people) and seven trials with MMSE-type tests after a mean 5 years (20,431 people). B vitamins lowered homocysteine by 28% and 26% respectively, but had no significant effect on memory, speed, executive function or global cognitive function (z score difference 0.00, 95% CI -0.05 to 0.06; and -0.01, 95% CI -0.03 to 0.02). A 25% reduction in homocysteine equated to 0.02 years of cognitive aging per year (95% CI -0.10 to 0.13), excluding benefits greater than one month per year of treatment.
Conclusions
Homocysteine lowering by using B vitamins had no significant effect on individual cognitive domains or global cognitive function or on cognitive aging.
Limitations
Cognitive measures differed between trials, with most contributing only end-of-treatment MMSE-type tests rather than change scores; participants were largely older adults without dementia, so effects in cognitively impaired or severely deficient people are not addressed.
Supplements Studied
Homocysteine lowering by using B vitamins had no significant effect on individual cognitive domains or global cognitive function or on cognitive aging.
Homocysteine lowering by using B vitamins had no significant effect on individual cognitive domains or global cognitive function or on cognitive aging.
Related Health Concerns
Study Details
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