Vitamin B Supplementation and Progression of Alzheimer Disease

Homocysteine elevation is associated with endothelial and vascular dysfunction, neurotoxicity, and high plasma amyloid levels. Previous short-term clinical trials of dietary B vitamin supplementation to lower homocysteine levels in people with normal or impaired cognitive function have yielded mixed results. In this multisite U.S. study, 409 adults (mean age, 76) with mild-to-moderate Alzheimer disease were randomized to daily supplementation with a combination of folate (5 mg), vitamin B₆ (25 mg), and vitamin B₁₂ (1 mg) or to a daily placebo tablet.

At 18 months, 344 participants had completed the trial; homocysteine levels were significantly lower in the treatment group, but progression of dementia did not differ between groups. No differe…