Free radicals are atoms or groups of atoms that have at least one unpaired electron, which makes them highly reactive.
Free radicals promote beneficial oxidation that produces energy and kills bacterial invaders.
In excess, however, they produce harmful oxidation that can damage cell membranes and cell contents. It is known that people who eat adequate amounts of fruits and vegetables high in antioxidants have a lower incidence of cardiovascular disease, certain cancers, and cataracts. Fruits and vegetables are rich in antioxidants, but it is not known which dietary factors are responsible for the beneficial effects. However, vitamin E also has an anticoagulant effect that can promote excessive bleeding. Moreover, other studies have had conflicting results.