Vitamins failed to slow mental decline in study
BOSTON, June 29 (Reuters) Vitamin therapy failed to slow the mental decline of older people who have high levels of an amino acid that has been associated with cognitive disorders, according to a new clinical trial.
The results, published in The New England Journal of Medicine showed that 127 volunteers aged over 64 and with high levels of homocysteine who 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,'' said a New Zealand team led by Jennifer McMahon of the University of Otago.
Earlier studies have shown that people with declining mental abilities tend to have high levels of the chemical. But it has been unclear whether using folic acid and B vitamins to bring the levels down would prevent or delay the deterioration.
The McMahon study was an attempt to find out.
In an editorial in the New England Journal of Medicine, where the study appears, Robert Clarke of the University of Oxford said that the experiment didn't have enough volunteers, didn't last long enough, and the mental sharpness of the people who received the placebo tablets didn't deteriorate fast enough to prove that the vitamins failed to affect the risk of dementia.
He said forthcoming results from about 20,000 people from a dozen studies on volunteers with heart or kidney disease may offer better evidence in the coming years.
This is the third study since March to question the benefits of reducing homocysteine levels. Two tests, also published in the New England Journal, showed that using B vitamins and folic acid to treat people with high homocysteine levels did not bring down their elevated risk of heart attack or stroke.
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