Vitamin therapy doesn't appear to slow the mental decline of older people who have high levels of an amino acid that has been associated with cognitive disorders.
The findings, published in the June 29 issue of the New England Journal of Medicine, showed that 127 volunteers older than 64 who had high levels of homocysteine and took vitamin therapy for two years had lower levels of the amino acid but performed no better in cognitive tests than 126 who received a placebo.
"The results of our trial do not support the hypothesis that homocysteine lowering with folate, vitamins B-12 and B-6 improves cognitive performance in healthy older people," one researcher said.
Earlier studies have shown that people with declining mental abilities tend to have high levels of the chemical. But it has been unclear whether folic acid and B vitamins would prevent or delay the deterioration.