Your body uses oxygen in the normal chemical reactions of living cells, including getting and using the energy from your food. In the process, oxygen can react with other compounds in your body and create highly unstable molecules known as free radicals. Environmental factors such as air pollution, tobacco smoke and ultraviolet radiation also generate free radicals that your body must protect against. Antioxidants help relieve the oxidative stress created by too many free radicals.
Identification
A free radical is a trouble-making molecule with one or more unpaired electrons that make it unstable and highly reactive. By donating an electron or two, antioxidants neutralize free radicals and protect your body tissues from damage that adversely affects your normal physiological function. Oxidative stress indicates an imbalance between your body's production of free radicals and your body's ability to handle them and prevent damage.
Effects
An electron without a partner quickly tries to regain stability by stealing an electron from a stable but vulnerable compound, which then becomes a free radical and steals an electron from another nearby molecule. Thus begins an electron-stealing chain reaction with free radicals producing more and more free radicals and initiating tissue damage in your body. Antioxidants stop the chain reaction by donating an electron of their own and remaining stable in their new state. In effect, an antioxidant sacrifices itself to stop the devastating proliferation of free radicals.
Significance
Your body sometimes uses free radical attacks of its own to kill viruses and bacteria. Usually, though, free radical attacks cause widespread damage. They damage cell membranes and create mutations in DNA. Scientists have implicated oxidative stress in the development of chronic diseases including cancer, heart disease and arthritis.
Foods rich in the antioxidant vitamin C seem to protect against certain types of cancers. Antioxidants, especially vitamin E, may protect against cardiovascular disease. The phytochemical resveratrol found in grapes and peanuts protects against cancer by limiting cell growth and protects against heart disease by limiting clot formation, according to Eleanor Whitney and Sharon Rolfes in "Understanding Nutrition."
Considerations
Eat a variety of foods low in saturated fat, trans fat and cholesterol to provide a natural source of antioxidant vitamins and phytonutrients, according to the American Heart Association. When you eat plenty of fruits and vegetables, you help your body fight disease. Nutrients and phytochemicals with antioxidants minimize free radical damage by limiting the formation of free radicals, destroying free radicals and repairing oxidative damage to your body. Whole foods, rather than dietary supplements, provide the best sources of vitamins and minerals because of their greater nutrition, fiber and protective substances.
Your body's natural defenses decline with age and unrepaired damage accumulates. If antioxidants are not available or if free radical damage is excessive, health problems develop. Dietary supplements may be appropriate in some cases if you are not able to eat enough healthy foods or have medical conditions that affect your ability to digest and absorb nutrients properly.
References
- American Heart Association: Antioxidant Vitamins
- "Understanding Nutrition, Ninth Edition"; Eleanor Noss Whitney and Sharon Rady Rolfes; 2002
- MayoClinic.com: Dietary supplements: Nutrition in a pill?
