Antioxidant Supplements Reduce Risk of Heart Disease: Epidemiologic vs Clinical Studies
Antioxidant Supplements Decease Risk of Heart Disease: Epidemiologic Studies Not Trumped by Clinical Trials
Epidemiologic studies, including results from at least four large cohorts, indicate that among the healthy population the long-term use of antioxidant supplements, specifically vitamin E and vitamin C, helps protect against heart disease. "It is puzzling how the American Heart Association's nutrition committee could recommend against the use of antioxidant supplements for primary prevention of heart disease, in the face of evidence such as this," said Annette Dickinson, Ph.D., president of the Council for Responsible Nutrition. "Even if recent secondary intervention trials have been disappointing, those results do not trump the epidemiological data on primary prevention." (Primary prevention is avoiding or delaying heart disease in healthy people; secondary prevention is avoiding a second heart attack or stroke in people who have already had one.)
A study of more than 80,000 nurses found that women who took vitamin E supplements for more than two years had a 41% reduction in risk of major coronary disease. (Stampfer 1993) A later study of the nurses' cohort found that women who took vitamin C supplements had a 27% reduction in risk of coronary heart disease. (Osganian 2003) A study of almost 40,000 male health professionals (mostly dentists) found that men who took vitamin E supplements for at least two years had a 37% reduction in risk of coronary disease. (Rimm 1993) A study in more than 11,000 elderly people found that those who used vitamin E supplements had a 47% reduced risk of coronary disease mortality, and those who used supplements of both vitamin E and vitamin C had a 53% reduced risk of coronary mortality. (Losonczy 1996) These are large and important effects. The exception is a study of almost 35,000 post-menopausal women that found a protective effect of vitamin E from conventional foods, but not from supplements ñ but the authors noted that relatively few of the women used vitamin E and they had no information on the duration of use. (Kushi 1996)
The American Heart Association's science advisory recognizes that the epidemiological data is compelling, but implies that such evidence applies only to the intake of antioxidants from conventional foods, and not from supplements. (AHA 2004) This is not the case, since the studies cited above specifically examined supplemental intake, and four of the five reported significant benefits in the primary prevention of heart disease associated with the use of antioxidant supplements in healthy populations.
What is the best advice for consumers? For overall health maintenance as well as potential protection against some chronic diseases, the Council for Responsible Nutrition recommends consuming the best possible diet, with lots of fruits and vegetables and two servings of fish per week; getting regular exercise; and supplementing those healthy habits with what UCLA's David Heber, M.D., has called the "basic four" nutritional supplements: a multivitamin, extra calcium, extra vitamin E, and extra vitamin C. (Heber 2001)
• AHA Science Advisory: Antioxidant vitamin supplements and cardiovascular disease. Circulation 2004; 110: 637-641.