Antioxidants are a classification of several organic substances. The organic substances include, but are not limited to, vitamins C, E, and A; a mineral called selenium; and a group of organic substances known as carotenoids (i.e.: beta-carotene). Carotenoids are pigments that add the color to a majority of fruits and vegetables. Oxygen causes a chemical reaction in your cells called oxidation, a by-product of normal metabolism. The result is the formation of molecules known as free radicals. Free radicals can damage cells and tissues in the body, leading to certain concerns such as heart disease, eye disease and ageing of the skin.