Antioxidants are thought to protect cells in the body from oxygen damage. This damage is thought to play an important role in health problems like heart disease or cancer. Antioxidants include vitamins and substances such as beta-carotene, vitamin A, vitamin C, vitamin E, and selenium. Antioxidants can be easily found in a variety of foods, but they are also sold as supplements and marketed for their health benefits. However, not all research has indicated that these supplements independently, or combined, have health benefits. In fact, some studies have indicated that certain antioxidant supplements may do more harm than good.
Researchers from Cochrane Database completed a review of previous trials examining the benefits of antioxidants. The review, published in Cochrane Database, found that antioxidants were not associated with health benefits and a few were associated with increased risk of dying.
The systematic review included 78 randomized trials with 296,707 adults. The trials evaluated the impact of antioxidants on death rates in adults. The average age of the participants was 63, but they ranged from 18 years old to 103 years old. The participants were healthy in 26 trials and had a stable disease in 52 trials. The supplements were given by mouth for an average of two years. The specific antioxidants involved included beta-carotene, vitamin A, vitamin C, vitamin E, and selenium.
In an overall analysis that included trials of all qualities, antioxidant supplements were not associated with reduced risk of death.
In an analysis of the 56 trials that were considered high quality:
Systematic reviews are considered reliable forms of research because they pool large volumes of information from several trials. The number of high quality trials that were used in this review makes the results more reliable. Similar results have also been found in a previous systematic review.
Despite these findings showing no benefits with antioxidants and potential harm from some, health supplements are still a big business with claims of illness prevention. You may have chosen antioxidant supplements to booster a poor diet or simply because you want to be more healthy. If you are generally healthy, antioxidant supplements may not be as helpful as claimed. You may be better off getting them through a healthy balanced diet with a variety of fruits, vegetables, nuts, grains, and lean proteins. Getting your antioxidants through diet may also decrease your chance of getting more of these substances than is needed. You may also save money by simply adding a few colorful fruits and vegetables to your diet rather than buying pills. However, certain medical conditions may require the use of supplements. In these cases, follow your doctor's recommendations.
Eat Right - American Dietetic Association
Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C. Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database Syst Rev. 2012 Mar 14;3:CD007176.
Last reviewed June 2012 by Brian P. Randall, MD