Questioning Benefit of Antioxidant Pills
Despite growing evidence for the value of dietary antioxidants such as vitamin E, it is still not clear whether taking them in pill form can reduce the risk of heart disease, a review of current research concludes.
“In view of these findings,” nutrition experts concluded, “the most prudent and scientifically supportable recommendation for the general population is to consume a balanced diet with emphasis on antioxidant-rich fruits and vegetables and whole grains.”
The recommendation comes in a report by Diane Tribble, a scientist at the Lawrence Berkeley National Laboratory and a member of the American Heart Assn.’s nutrition committee, which reviewed dozens of studies. It was published in the heart association’s journal Circulation.
“Although some studies have shown that foods rich in antioxidants are associated with a reduced risk of heart disease, that doesn’t necessarily mean that high levels of antioxidants achieved by consuming vitamin pills will provide similar benefits--or are even safe,” Tribble said.
Antioxidants--including vitamin E, vitamin C and beta-carotene, a form of vitamin A--have attracted medical attention because they counteract oxidants, which are believed to play a role in causing atherosclerosis, the buildup of fatty deposits along artery walls. Blockages caused by atherosclerosis can lead to heart attack or stroke.
Much of the evidence for the antioxidants’ possible benefit comes from so-called observational studies, which can be difficult to interpret.
For example, a large federal health survey found that people who reported taking high doses of vitamin C had a significantly lower death rate from heart disease during a 10-year period. But many factors, including overall diet, might have influenced such an outcome.
Foods rich in vitamins C and E and beta-carotene also tend to be low in saturated fat and cholesterol and high in fiber, Tribble’s report noted. Sorting out which ingredient or habit is responsible for any given health effect is difficult.
Evidence for a health benefit from vitamin E is stronger in people who already have had a heart attack or stroke. But those encouraging findings, Tribble said, need to be confirmed by larger studies. And some studies of beta-carotene supplements have found no benefit, particularly in high-risk patients, the overview noted.
