Dementia study questions advice on taking supplements

13 November 2014 - BBC News

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Taking vitamin B12 and folic acid supplements does not seem to cut the risk of developing dementia in healthy people, say Dutch researchers.

In one of the largest studies to date, there was no difference in memory test scores between those who had taken the supplements for two years and those who were given a placebo.

B vitamins have been linked to Alzheimer's for some years, and scientists know that higher levels of a body chemical called homocysteine can raise the risk of both strokes and dementia.Vitamin B12 and folic acid are both known to lower levels of homocysteine.

That, along with studies linking low vitamin B12 and folic acid intake with poor memory, had prompted scientists to view the supplements as a way to ward off dementia.

Yet in the study of almost 3,000 people - with an average age of 74 - who took 400 micrograms of folic acid and 500 micrograms of vitamin B12 or a placebo every day, researchers found no evidence of a protective effect.

All those taking part in the trial had high blood levels of homocysteine, which did drop more in those taking the supplements.

But on four different tests of memory and thinking skills taken at the start and end of the study, there was no beneficial effect of the supplements on performance.

The researchers did note that the supplements might slightly slow the rate of decline but concluded the small difference they detected could just have been down to chance.