A recent analysis of eight published studies shows that boosting intake of folic acid, an important B vitamin, may reduce the risk of a debilitating stroke by 18 percent or more.

Middle-aged women may have reason to pay particular attention to the new finding: In a recent survey, women 45 to 54 years old were more than twice as likely as men in the same age group to have had a stroke. Researchers say that rising rates of heart disease and weight gain among women may be to blame.

Stroke deaths have dropped significantly since the federal government mandated in 1998 that grains be fortified with folic acid, The B vitamin lowers blood levels of homocysteine, an amino acid linked to vascular problems. Studies on folic acid for heart health have been inconclusive. Experts recommend that Americans consume at least 400 micrograms (0.4 milligrams) of folic acid every day.