According to a new analysis of studies, antioxidants such as beta carotene and vitamin E do not cut the risk of heart disease; in fact, beta carotene may even slightly increase it. Antioxidants have been associated with reductions in heart diseases. However researchers at the Cleveland Clinic Foundation found that the use of supplements containing beta carotene and vitamin A (a beta carotene metabolite) should be actively discouraged and that clinical studies using the antioxidant be discontinued. In addition, they also discouraged similar investigations involving vitamin E for heart disease treatment or prevention. In the study, the researchers reviewed seven previously published trials of vitamin E treatment and eight trials of beta carotene treatment. All of the trials included at least 1,000 patients in which patients were randomly assigned to take the supplements or a "control" treatment. The dose range for vitamin E was 50-800 IU and for beta carotene 15-50 mg. The follow-up ranged from 1·4 to 12·0 years. The vitamin E trials involved a total of 81,788 patients and the beta carotene trials involved 1,38,113 patients. The lack of efficacy led the researchers not to support the continued use of vitamin E treatment. In fact, one trial showed that vitamin E blocked the effects of otherwise established good treatments with statins and niacin, and there was no evidence they are good and there is a hint that they may be harmful. In fact it was recommend that vitamin E be excluded in trials of patients at high risk of coronary artery disease. They found that vitamin E provided no benefit in overall death rate, cardiovascular death, or cerebro-vascular accident. Beta carotene led to a small but significant increase in all-cause death, and a small increase in death due to heart disease. Researchers found the beta carotene results were especially concerning since the doses that produced this effect were within the range commonly used in over-the-counter preparations. They did not recommend the routine use of vitamin E to reduce cardiovascular (heart disease) risk and noted that the small harmful effect seen for beta carotene was largely due to studies that included a lot of smokers.

The Lancet, June 2003; Vol. 361 (9373)