The vitamin industry has long touted antioxidants as a way to improve health by filling in gaps in diet, but a new review of studies found no evidence that the nutrition supplements extend life. Worse, the review authors said that some antioxidants could increase risk for death.
The reviewers want more regulation of the nutraceuticals industry, but an antioxidant researcher with the U.S. Department of Agriculture said that call for stricter monitoring overreaches the conclusions of the review.
The meta-analysis of 67 randomized studies found that supplemental antioxidants do not reduce mortality and that some including vitamin A, beta-carotene and vitamin E could increase mortality. The review combined evidence from more than 200,000 people.
The harmful effects of antioxidant supplements are not confined to vitamin A, said review co-author Christian Gluud, M.D. Our analyses also demonstrate rather convincingly that beta-carotene and vitamin E lead to increased mortality compared to placebo.
The review appears in the latest issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
Most people do eat not enough fruits and vegetables to ensure an adequate intake of vital nutrients. However, it is unclear if supplementation can provide benefits akin to a healthy diet and if some antioxidants are, in fact, harmful. Antioxidants are nutrients such as vitamin E, vitamin C, or beta carotene that have been marketed as a way to counter the damaging effects of oxygen in the tissues.
The review included studies of healthy adults and adults diagnosed with specific, stable medical conditions. The authors excluded studies with children or pregnant women, or studies that evaluated su
|Contact: Lisa Espoito|
Center for the Advancement of Health