Vitamin B Supplementation and Cognition
In older men, supplementation did not affect 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, above 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 (above 15 mcmol/L) and men with mild cognitive impairment at baseline — the investigators found no benefit from vitamin B supplementation.
Comment: This study adds to a growing body of evidence that vitamin B supplementation does not favorably affect cognition in older adults. One possible inference is that homocysteine is a marker — not a cause — of cognitive impairment in older adults.
Allan S. Brett, MD
Published in Journal Watch General Medicine November 10, 2010
Citation(s): Ford AH et al. Vitamins B12, B6, and folic acid for cognition in older men. Neurology 2010 Oct 26; 75:1540. (http://dx.doi.org/10.1212/WNL.0b013e3181f962c4)