New findings do suggest that folic acid may slow the declines in memory that can occur with age. Dutch researchers recently presented compelling evidence from a three-year study that included 818 adults between the ages of 50 and 70, none of whom were having any memory problems. During the study, the participants took either a placebo or 800 mcg folic acid (twice the amount recommended for women of childbearing age to protect against birth defects). Results showed that those who took the folic acid had memory scores equal to people five and a half years younger. The folic acid group in the study also did better in information processing and muscle skills. The study was conducted by researchers at Wageningen University in the Netherlands and reported at the Alzheimer's Association International Conference on Dementia Prevention.
While interesting, these results fall far short of showing that taking folic acid can prevent Alzheimer's disease. Since none of the participants suffered from Alzheimer's, the study couldn't assess whether or not folic acid slowed progression of the disease. But results did indicate that the supplement may offer some protection against normal age-related declines in memory.
Earlier studies have suggested that vitamins C and E taken together might slow the progress of Alzheimer's. One, from Johns Hopkins University, found that people over 65 least likely to develop the disease were those who had been taking individual supplements of vitamins C and E. The study included thousands of individuals aged 65 and older in Cache County, Utah, who were followed from 1995 to 2000. More research is needed to determine whether or not vitamins C and E really do offer protection. The study was published in the January 2004 issue of the Archives of Neurology.
Other research has shown that people with high blood levels of homocysteine have twice the normal risk of Alzheimer's. Homocysteine is a toxic amino acid also linked to heart attacks and strokes; it is more likely to be high if your diet is high in animal protein and low in fruits and leafy vegetables (good sources of folic acid and other B vitamins). Interestingly enough, the treatment for high levels of homocysteine in the blood is supplemental B-vitamins including folic acid. Although we have no proof that B vitamins and folic acid protect against Alzheimer's, I do recommend taking a multivitamin that provides at least 400 micrograms of folic acid to help protect against heart disease, strokes and, perhaps, Alzheimer's disease. And I've started taking 800 micrograms a day myself.
Andrew Weil, M.D.