Medical experts say the number of Alzheimer's victims could be cut in half simply by delaying the onset of the disease by five years. The 30 nuns lived together in Mankato, Minn., and ate the same food from the same kitchen. But Snowdon said differences in their folic acid levels can be explained by the fact that some took vitamin supplements, and some probably had genetic factors that caused their bodies to absorb folic acid at different rates. UK researchers said they decided to look at folic acid after scientists at Oxford University in England noticed last year that Alzheimer's patients whose blood had high levels of folic acid developed fewer symptoms. Dr. A. David Smith, an Oxford pharmacologist, says Snowdon's findings support Oxford's results.
Folic acid is known to be important in the development of the brain and spinal cord.
Pregnant women are advised to take folic acid to prevent birth abnormalities such as spina bifida and mental retardation. The U.S. Food and Drug Administration now requires manufacturers to fortify wheat, rice and other grain products with folic acid, a move that is gradually eliminating folic acid deficiency in the United States. But UK doctors say that, based on their findings, people at risk of Alzheimer's still might consider taking a folic acid supplement as an additional hedge against the disease. But Oxford's Smith said that urging people to take supplements might be premature. Taking folic acid could mask this deficiency, possibly causing physical harm, he said.