Antioxidants: definitions and food sources

A biological antioxidant is a compound that protects biological systems against the potentially harmful effects of processes or reactions that cause excessive oxidation.

Although oxidation is an important process for sustaining life, it produces free radicals (‘hydroxyl radical’ or ‘superoxide anion’ or ‘hydrogen peroxide’), which cause chain reactions in the body that eventually damage the cells.

Antioxidant can prevent this destructive oxidation of other molecules in the body. Antioxidants stop the chain reaction by removing the free radicals and by stopping other oxidation reactions.

Antioxidants are found naturally in many foods, primarily fruits and vegetables. They are also available as supplements.

Hydrophilic compounds, such as vitamin C, thiols, and flavonoids, as well as lipophilic compounds such as vitamin E, vitamin A, carotenoids, and ubiquinols, are the best-known natural antioxidants.

Some minerals, such as selenium are also considered to have antioxidant properties. Many studies report benefits of antioxidants in preventing heart disease, neurological diseases, macular degeneration and even some cancers.
Antioxidants: definitions and food sources