Folic acid & stroke

Can some B-vitamins prevent a second stroke? People with high blood levels of homocysteine have a higher risk of stroke (and heart disease), and three B-vitamins (folic acid, B-6, and B-12) lower homocysteine.

But in a new study of 3,680 stroke victims, those who were given high doses of those B-vitamins for two years were just as likely to have a second stroke as those who got low doses. Why? It's possible that:

* Fortification interfered. During the study, companies started fortifying more foods with folic acid, so the low-dose group may have consumed more of the vitamin than researchers planned on. That may have made it harder to see whether those who took high-dose supplements had a lower risk of stroke.

* The study was too short. It may take more than two years to correct the damage caused by high homocysteine levels.

* Homocysteine may not matter. It's possible that homocysteine doesn't damage blood vessels, but just occurs along with something else that does.

What to do: Take an ordinary multivitamin-and-mineral to make sure you get enough folio acid and other vitamins. Even in this study, people who started with high homocysteine levels (before they got any vitamins) had a higher risk of stroke.

Journal of the American Medical Association 291: 565, 2004.

COPYRIGHT 2004 Center for Science in the Public Interest
COPYRIGHT 2004 Gale Group