Folate, the same B vitamin that helps prevent birth defects, may also ward off another serious problem: high blood pressure.

An analysis from the Nurses’ Health Study found that women between the ages of 26 and 46 who took at least 800 micrograms of folate a day were nearly a third less likely to develop high blood pressure than those who got 200 mcg or less. Older women cut their risk by 13 percent. Folate has been shown to lower levels of homocysteine, a blood compound associated with cardiovascular disease, which may explain the findings.

Still, 800 mcg is a lot of folate, even more than most people get from folate-rich foods such as spinach, peas, and fortified breads and cereal.

The best way to hit that number? “Since foods became fortified, most people likely get at least 400 mcg a day from their diet,” says Harvard’s John Forman, lead author of the study. “And a typical multivitamin will get you 400 more.”