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    Paul Y. Takahashi, M.D.

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Question

Folic acid supplements: Can they slow cognitive decline?

I've heard that folic acid supplements can improve cognitive function in older adults. Could those with Alzheimer's disease also benefit from folic acid?

Answer

from Paul Y. Takahashi, M.D.

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 may be referring assessed the effect of folic acid supplements on cognitive performance in 818 older adults with deficient 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.

However, again, the participants in this study were already at some risk of cognitive decline because of deficient blood levels of folate. So the results of this study can neither be generalized to all older adults nor to those with Alzheimer's disease.

A 2008 review of eight 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.

So although it doesn't appear that everyone should take a folic acid supplement, it may be something worth discussing with your doctor. Keep in mind that if you live in the United States, many foods such as breads and cereals are fortified with folic acid. If you are at high risk of developing dementia or have already experienced some cognitive decline, checking your folic acid levels may be a reasonable next step.

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References
  1. Durga J, et al. Effect of 3-year folic acid supplementation on cognitive function in older adults in the FACIT trial: A randomised, double blind, controlled trial. The Lancet. 2007;369:208.
  2. Malouf R, et al. Folic acid with or without vitamin B12 for the prevention and treatment of healthy elderly and demented people. Cochrane Database of Systematic Reviews. 2008:CD004514.
  3. Bauer BA (expert opinion). Mayo Clinic, Rochester, Minn. March 22, 2009.
  4. Takahashi PY (expert opinion). Mayo Clinic, Rochester, Minn. March 22, 2009.

AN01602

Sept. 10, 2009

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