Vitamin B Supplementation and Cognition

Because high plasma homocysteine levels are associated with cognitive impairment in epidemiologic studies, in multiple clinical trials researchers have examined whether vitamin B supplementation — which lowers homocysteine levels — improves cognition or delays onset of cognitive impairment in older adults; results have been mostly negative. In a new study, Australian researchers randomized 299 community-dwelling hypertensive men (age, ≥75) without dementia to receive either placebo or a combination of vitamin B₆, vitamin B₁₂, and folic acid.

During 2 years of treatment, no differences between groups were noted on several measures of cognition. Even in subgroups in which benefit seemed likely — men with high baseline homocysteine levels (≥15 µmol/L) and men with mild cognitive impairment at baseline — the investigators found no benefit from vitamin B supplementation.