Taking vitamin B12 and folic acid supplements may not reduce the risk of memory and thinking problems after all, according to a new study published in the November 12, 2014, online issue of Neurology®, the medical journal of the American Academy of Neurology. The study is one of the largest to date to test long-term use of supplements and thinking and memory skills.
The study involved people with high blood levels of homocysteine, an amino acid. High levels of homocysteine have been linked to memory loss and Alzheimer's disease.
"Since homocysteine levels can be lowered with folic acid and vitamin B12 supplements, the hope has been that taking these vitamins could also reduce the risk of memory loss and Alzheimer's disease," said study author Rosalie Dhonukshe-Rutten, PhD, of Wageningen University in Wageningen, the Netherlands.
Early observational studies showed there may be some benefit to thinking and memory skills in taking folic acid and vitamin B12, but the results of later randomized, controlled trials were less convincing.
For the current study, 2,919 people with an average age of 74 took either a tablet with 400 μg of folic acid and 500 μg of vitamin B12 or a placebo every day for two years. Tests of memory and thinking skills were performed at the beginning and end of the study. All of the participants had high blood levels of homocysteine.
"While the homocysteine levels decreased by more in the group taking the B vitamins than in the group taking the placebo, unfortunately there was no difference between the two groups in the scores on the thinking and memory tests," said Dhonukshe-Rutten.
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