Harvard Women's Health Watch

In the journals: No cardiovascular help from B vitamins in high-risk women

In the journals

No cardiovascular help from B vitamins in high-risk women

Taking folic acid (vitamin B9) and vitamins B6 and B12 does not reduce the likelihood of a heart attack or stroke in women at high risk for cardiovascular disease (CVD). That's the conclusion of a randomized trial involving more than 5,000 women with three or more coronary risk factors or a history of CVD. Researchers at Harvard Medical School found that the supplements were no better than a placebo, even though they lowered blood levels of homocysteine, an amino acid that's been linked to heart and vascular trouble. Results were published in The Journal of the American Medical Association (May 7, 2008).

Observational studies have found a link between high blood levels of homocysteine and cardiovascular problems, and research has shown that folic acid, B6, and B12 supplements bring down homocysteine levels. Yet in earlier randomized trials, lowering homocysteine through folic acid and B vitamin therapy has not prevented heart attacks or strokes in people with CVD. Harvard researchers believed that these trials had not lasted long enough (most had less than four years of follow-up), and had included too few women. (Some evidence suggests that women gain more from homocysteine-lowering strategies than men do.)

To remedy the situation, investigators at Boston's Brigham and Women's Hospital and the Harvard School of Public Health tested a combination pill containing 2.5 milligrams (mg) of folic acid, 50 mg of vitamin B6, and 1 mg of vitamin B12. In the study, 5,442 women ages 42 and over who had CVD or were at high risk for it received either the combination pill or a placebo. All participants were already enrolled in an ongoing trial of antioxidant vitamins (the Women's Antioxidant and Folic Acid Cardiovascular Study). During 7.3 years of follow-up, despite a nearly 20% greater drop in homocysteine in the treatment group, the two groups had about the same rate of heart attacks, strokes, and deaths from CVD.

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