Folic acid supplements: Can they slow cognitive decline?

A recent study suggests that folic acid supplements can improve cognitive function in older adults. Could those with Alzheimer's disease also benefit from folic acid?

- John / Tennessee

Mayo Clinic geriatrician Paul Takahashi, M.D., and colleagues answer select questions from readers.

Answer

There's no conclusive evidence that folic acid supplements improve cognitive function in older adults or in people with Alzheimer's disease or other types of dementia.

The study to which you refer assessed the effect of folic acid supplements on cognitive performance in 818 older adults with low blood levels of folate. Low folate levels are associated with poor cognitive performance in the general population.

Participants were randomly assigned to take 800 micrograms of folic acid or a placebo for three years. The study, which published in January 2007, showed cognitive function was significantly better in those who took folic acid supplements than in those who did not.

It's important to note that participants in this study didn't represent the general population — but instead a group of people already at some risk of cognitive decline. So the results of this study can neither be generalized to all older adults nor to those with Alzheimer's disease.

In addition, a 2003 review of four randomized, controlled trials found that the use of folic acid supplements has no benefit on cognitive function in healthy adults or in those with mild to moderate cognitive decline or dementia.