Antioxidants are substances that may protect cells in your body from free radical damage that can occur from exposure to certain chemicals, smoking, pollution, radiation, and as a byproduct of normal metabolism. Dietary antioxidants include selenium, vitamin A and related carotenoids, vitamins C and E, plus various phytochemicals such as lycopene, lutein, and quercetin.
You can find these antioxidants in many different foods. There are large amounts of antioxidants in fruits, vegetables, nuts, and whole grains and smaller amounts of antioxidants in meats, poultry and fish.
Health Benefits of Antioxidants
Consuming foods rich in antioxidants may be good for your heart health and may also help to lower your risk of infections and some forms of cancer. Increase your antioxidant intake by eating more nuts, seeds, legumes, fruits and vegetables.
Antioxidants in Dietary Supplements
Antioxidants are available as dietary supplements, but research doesn't indicate that these supplements are beneficial. While research supports increasing your intake of dietary sources, the results are not as impressive when the individual antioxidants are extracted and studied alone.
Antioxidant extracts often show impressive results in laboratory studies (test tubes, lab dishes and sometimes in lab animals), but when they're used in human clinical trials, the results for disease and death prevention have been disappointing. One exception was the National Eye Institute study of age-related eye disease, which suggested that a combination of antioxidants reduced the risk of developing advanced stages of age-related macular degeneration.
Some antioxidant supplements may be detrimental to your health when taken in large doses and may interact with certain medications. Large amounts of vitamin A supplements may cause birth defects when taken by pregnant women, and may increase your risk for cardiovascular disease and cancer.
Taking large doses of vitamin E (over 400 International Units per day) has been associated with a possible increase in overall mortality. This doesn't apply to a typical multivitamin supplement. The amounts of vitamins A and E included in multivitamin tablets are small in comparison.
If you're thinking about taking larger amounts of any antioxidant supplements, you should speak with a health care provider first.
Academy of Nutrition and Dietetics. "What Is an Antioxidant?" Accessed March 15, 2011. http://www.eatright.org/Public/content.aspx?id=3813.
United States National Institutes of Health, National Cancer Institute. "Antioxidants and Cancer Prevention: Fact Sheet." Accessed March 15, 2011. http://www.cancer.gov/cancertopics/factsheet/prevention/antioxidants.
United States National Institutes of Health, National Center for Complementary and Alternative Medicine. "Antioxidant Supplements for Health: An Introduction." Accessed March 15, 2011. http://nccam.nih.gov/health/antioxidants/introduction.htm.