Life's everyday bodily processes (including normal cell functions) and exposure to various elements can lead to the formation of unstable organic compounds called free radicals; these are pretty wild substances. The body uses substances called antioxidants to limit the damage free radicals can inflict. When antioxidants are exhausted it causes oxidative stress, a common problem in chronic inflammatory conditions like HIV infection.
Free radicals are made by the body in response to toxic exposure (sunburn, for instance), infection, exercise, and other exposures. While some of this process is part of the protective mechanism to kill invasive infections, excessive production can lead to tissue damage. Some of the potential consequences of excessive free radical production include cancer, cardiovascular disease, and accelerated aging processes.
There are several different types of antioxidants that a typical body has handy to keep the free radicals in check. These include fat-soluble nutrients like vitamin E and beta-carotene; water-soluble nutrients like vitamin C; enzymes like glutathione peroxidase and superoxide dismutase; and very small compounds like glutathione. The theory is that if you can keep a steady supply in the body, you should be able to limit the damage that is so common with disease and even everyday life. Nutrient-based antioxidants, found in a variety of food sources, are a simple way to reap this benefit.
Vitamin E. This can help prevent fat oxidation in cell membranes'kind of like preserving cells against becoming 'rancid.' You can find vitamin E in wheat germ and oils. Smaller amounts are found in fruits, vegetables, fish, and meats. The dietary reference intake recommendations are for 15 milligrams a day, and some have recommended a daily intake of 30 to 50. A 1,000-milligram dose of vitamin E in supplement form is considered the upper limit, or the level at which toxic effects may occur. However, this level in food forms might be a safer bet.
Beta-carotene. One of the more than 600 types of carotenes found in foods, it has been touted for its antioxidant and transient immunoenhancing effects. You can find beta-carotene in fruits; yellow, orange, and deep-green vegetables; and sweet potatoes. No dietary reference intake is established.
Vitamin C. This water-soluble antioxidant's main effects are actions in plasma and to regenerate vitamin E as an antioxidant. You can get vitamin C from fruits and vegetables. It is easily oxidized in cooking or long-term exposure to air, which is why orange juice products often contain extra vitamin C. The dietary reference intake is 75 milligrams for women and 90 for men; the upper limit is 2,000 milligrams. You should note that excessive vitamin C can interfere with copper metabolism, so keeping things in balance is important.
Glutathione peroxidase. This enzyme scavenges free radicals but is dependent on selenium for maximum benefit. The dietary reference intake for selenium is 55 micrograms; the upper limit is 400 micrograms. While selenium is important to immune function, excessive amounts can actually impair immune function. You can find selenium in meat and seafood. There can be a good amount in fruits or vegetables, but this is dependent on the selenium content of the soil in which they are grown.
Whether to use supplements or not is an important question'and there is no clear answer. Some authorities suggest that because there are multiple beneficial elements in food sources with antioxidants that improve antioxidant power, supplements are not necessary. A general consensus is that multiple nutrients are probably a better bet than single nutrients and that a balance is essential.
Regardless of what your health care team recommends and what you choose to do with supplemental nutrients, however, consuming five to seven servings of fruits and vegetables each day is a great start toward a goal of maintaining a strong level of antioxidants.
Fields-Gardner is the director of services for the Cutting Edge, an HIV nutrition company in the Chicago area. She is a member of the American Dietetic Association's Dietetic Practice Group on HIV and AIDS.
