Originally Published: March 15, 1996 - Last Updated / Reviewed On: February 11, 2013
What is the role of antioxidants in health?
Before discussing their role in maintaining good health, let's first clarify what antioxidants are. "Antioxidant" is the collective name for the vitamins, minerals, carotenoids, and polyphenols that protect the body from harmful free radicals. The most well known antioxidants include the vitamins A (found in liver, dairy, and fish), C (found in bell peppers and citrus fruits), E (found in oils, fortified cereals, seeds, and nuts), and the mineral selenium (found in Brazil nuts, meats, tuna, and plant foods). The carotenoids beta-carotene, lutein, and lycopene also have high antioxidant activity and are responsible for adding color to many fruits and vegetables. Carrots and pumpkins wouldn't be orange without beta-carotene, for example. Lutein, also important in eyesight, is abundant in leafy green vegetables. Lycopene is present in red fruits and vegetables, most notably in tomatoes. No wonder why many experts stress the importance of eating a "colorful" diet!
So why are they called antioxidants? The name is indicative of the mechanism by which they help prevent disease. In humans, a small but significant percentage of oxygen molecules in the body will become electrically charged due to natural cellular activity and/or exposure to environmental factors such as tobacco smoke and radiation. The oxygen molecule becomes a "free radical" as it undergoes this process of oxidation. Free radicals are highly reactive as they try to steal electrons from other molecules, including DNA and cellular membranes. They will continue to react with other cellular molecules in a chain-reaction mechanism. This chain reaction of free radicals can damage cells, which may play a role in the development of certain conditions like heart disease and cancer. Antioxidants, however, stop the chain-reaction by giving up electrons and neutralizing free radicals so that they cannot induce any more oxidative damage. Unlike other molecules, antioxidants do not become reactive when they lose an electron.
Many studies have shown the link between free radicals and a number of degenerative diseases associated with aging. Thus, it is possible that antioxidants can be beneficial in reducing the incidence of cancer, cardiovascular disease, cognitive impairment, Alzheimer's disease, immune dysfunction, cataracts, stroke, and macular degeneration.
Read any fitness magazine, watch a few television ads, or simply pass by your local health food store, and notice the benefits of the latest supplement being touted. While new products emerge frequently, it is best to remember that vitamin and mineral supplements are not to be used as substitutes for a healthy, well-balanced diet. In fact, due to many conflicting studies on the effects of antioxidant supplements, the American Heart Association does not currently recommend using antioxidant vitamin supplements. It is also important to note that we can "over-supplement" our bodies, taking much more than the recommended daily value of certain vitamins and minerals. Vitamins A and E are fat soluble, meaning that excess amounts are stored in the liver and fatty tissues, instead of being quickly excreted, creating a risk of toxicity. Your best bet is to eat a diet rich in fruits, veggies, and whole grains.
For information on cancer, heart disease, and antioxidants (as well as on healthy diets, vitamins and minerals, etc.), you can visit the the National Cancer Institute website. Additional resources on supplements are provided by the National Institute of Health's Office of Dietary Supplements.
Remember, a balanced diet rich in colorful fruits and vegetables can provide you with immediate health and energy benefits and help fight the effects of aging for years to come. Happy antioxidizing!