BOSTON—Results from the Women’s Antioxidant Cardiovascular Study, published in the Archives of Internal Medicine (2007;167(15):1610-18), suggest supplementation with vitamins C and E plus beta-carotene did not reduce cardiovascular events in women at high risk for cardiovascular disease (CVD). Researchers from Brigham & Women’s Hospital and Harvard Medical School followed 8,171 women (age 40 years or older) from 1995/1996 to 2005; all the women had a history of CVD or three or more risk factors (i.e., hypertension, high cholesterol, obesity). The women received 500 mg/d ascorbic acid, 600 IU every other day of vitamin E, 50 mg of beta-carotene every other day, or a placebo in a 2x2x2 factorial design.
During the average study period of 9.4 years, 1,450 women had one or more cardiovascular events for a total of 275 heart attacks, 298 strokes, 889 coronary revascularization (bypass or angioplasty) procedures, and 395 cardiovascular deaths. There was no overall effect of ascorbic acid or beta-carotene on the primary combined end point (CVD morbidity and mortality) or on the individual secondary outcomes of myocardial infarction, stroke, coronary revascularization or CVD death. Women with prior CVD who took vitamin E did have a marginally significant reduction in the primary outcome. In addition, women who received both ascorbic acid and vitamin E experienced fewer strokes.
“Overall, we found no benefit on the primary combined end point for any of the antioxidant agents tested, alone or in combination,” the authors conclude. “We also found no evidence for harm. While additional research into combinations of agents, particularly for stroke, may be of interest, widespread use of these individual agents for cardiovascular protection does not appear warranted.”
Andrew Shao, Ph.D., vice president, scientific and regulatory affairs, Council for Responsible Nutrition (CRN), said: “These results are encouraging, with the expectation that antioxidant supplements are not a ‘magic bullet’ for reversing chronic disease, but that taking antioxidant supplements for an extended period of time may offer subtle beneficial effects on chronic disease risk.” He also pointed out, along with the study authors, that this study contradicts several recent meta-analyses of antioxidant supplements, which found antioxidants and vitamin E may adversely impact mortality. This study showed that there was no overall effect on mortality and no statistically significant differences among groups for adverse effects. “This study is an interesting addition to the current scientific literature, and more research should be done, particularly to detect the effects of antioxidants on longer latency diseases, such as cardiovascular disease and cancer,” said Dr. Shao. “In the meantime, consumers should not deprive themselves of antioxidant supplements, including vitamin E.”
