Antioxidant Vitamin Supplements and Cardiovascular Disease Risk Reduction
The American Heart Association (AHA) has released a science advisory on the effects of antioxidant vitamin supplements on reducing the risk of cardiovascular disease. The full report appears in the August 3, 2004, issue of Circulation and is available online at http://circ.ahajournals.org/cgi/content/full/110/5/637.
The authors found that clinical trials generally have failed to demonstrate a beneficial effect of antioxidant supplements on cardiovascular morbidity and mortality. This lack of efficacy was demonstrated consistently for different doses of various antioxidants in diverse populations. Some smaller studies did show benefits from G-tocopherol, G-tocopherol plus slow-release vitamin C, and vitamin C plus vitamin E on cardiovascular end points.
There is some evidence that antioxidant supplements may have adverse effects on cardiovascular end points. Some study results showed that antioxidant supplements may have interfered with the efficacy of statinplusniacin therapy, and that the addition of antioxidant vitamins blunted the expected rise in the protective high-density lipoprotein (HDL)-2 cholesterol and apolipoprotein A1 subfractions of HDL.
According to the advisory, the scientific data do not justify the use of antioxidant vitamin supplements for the prevention and treatment of cardiovascular disease. There are no consistent data to show that consuming micronutrients at levels exceeding those provided by a dietary pattern consistent with the AHA Dietary Guidelines will provide additional benefit. The authors state that this position is consistent with evidence-based guidelines for prevention of cardiovascular disease in women, which was released in 2004 by the AHA, and guidelines for patients with chronic stable angina released in 2002 from the American College of Cardiology. The advisory recommends achieving cardiovascular risk reduction through long-term consumption of diets that are consistent with the AHA Dietary Guidelines and high in food sources of antioxidants and other cardioprotective nutrients, such as fruits, vegetables, whole grains, and nuts; long-term maintenance of a healthy body weight through balancing energy intake with regular physical activity; and attaining desirable blood cholesterol and lipoprotein profiles and blood pressure levels.