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Folic acid supplements improve some aspects of mental function in older men and women
(May 2007)

Whether increasing folic acid in the diet or taking folic acid supplements slows the memory loss and thinking capacities that occur with aging or actually reverses such loss is unclear.  The studies have been inconsistent and, for the most part, negative.  A new report from the Netherlands is quite interesting.  The investigators enrolled 818 people, average age 60 years, 70 percent men, and then gave 800 micrograms (a very good dose) of folic acid daily for three years to half of the group; the other half received an inactive placebo and served as controls.  The participants had low folate intake (less than 200 micrograms a day; recommended daily intake is 400 to 800 micrograms), blood levels of folic acid in the low normal range, and blood homocysteine levels at the top of the normal range (homocysteine levels are supposed to increase arterial hardening leading to stroke and heart attack; giving good amounts of folic acid will lower homocysteine levels).  At the beginning and end of the study, multiple tests were given to measure short-term memory, information processing speed, word fluency, attention, and other components of mental functioning.

At the end of the three-year period, those given folic acid did better in regard to short-term memory, information processing speed, and something called sensorimotor speed.

As expected, homocysteine blood levels fell in those given folic acid.  The improvement in mental function was found only in those who, at enrollment, had higher than average homocysteine blood levels.

Commentary: This is a very interesting study, but it is not without issues.

- Although blood folate levels were within normal limits, they were still quite low and dietary folate was clearly inadequate.  These results may not apply to the United States where food fortification results in far better folate intake.

- The participants were chosen on the basis of a relatively high homocysteine blood level.  The assumption was that high homocysteine levels would lead to arteriosclerosis of vessels leading to and in the brain and that reduction in those blood levels by folic acid administration would improve brain function.  The only problem with that assumption is that there is very little evidence to support it. Thus far, somewhat surprisingly, lowering homocysteine levels by giving folic acid has not produced much benefit.

- The authors say their results in regard to memory apply to both short and longer term (delayed) memory, but their test of delayed memory was a 20 minute hiatus between being given words and being tested for recall.  That is quite different from the memory problems faced by most older persons.

Durga, J., et al.  Effect of 3-year folic acid supplementation on cognitive function in the FACIT trial.  The Lancet.  Vol 369 (January 20) Pgs 208-216.  2007.

The importance of a good folic acid intake is clear, especially for the heart and prevention of anemia and maybe as an aid in preventing strokes.  Its role in preventing the mental function loss so frequent in older people is less clear.  This study must be repeated in older persons and include those with much better folate intake and a greater percentage with lower homocysteine levels.  If all older people followed our recommendation, it would be difficult to design such a study because we advocate a folic acid supplement for all those over age 60 since, in older persons, dietary folate is not well absorbed from the intestinal tract.