Free radicals are atoms or groups of atoms with an odd (unpaired) number of electrons that are produced when the body breaks down food, or by environmental exposures like tobacco smoke and radiation. When these free radicals react with important cellular components such as DNA or the cell membrane, they cause cell damage leading to poor cell functioning or cell-death. They may play a role in heart disease, cancer and other diseases. To prevent free radical damage the body has a defense system of antioxidants.
Antioxidants are molecules which can safely interact with free radicals and protect cells against them. The principle micronutrient (vitamin) antioxidants are vitamin E, beta-carotene, and vitamin C. The body cannot manufacture these micronutrients so they must be supplied in the diet. Antioxidants can be found in fruits and vegetables, nuts, grains, and some meats, poultry and fish.1