Free radicals are unstable molecules within the body that attack and destroy benign cells making the body vulnerable to disease.

They destroy the biochemical processes within cells and compromise the immune system which makes the body vulnerable to disease. Free radicals are also known as oxidants and to neutralize them you need to take AntiOxidants.

Antioxidants can be categorized as a) water-soluble or b) fat-soluble and divided according to source of origin.

Within the body
a) Superoxide dimutase (SOD) - prevents the damage caused by the toxic oxygen molecule known as superoxide.

b) Glutathione - is an amino acid which is converted by our bodies into glutathione peroxidase, a powerful antioxidant. Glutathione is a major cellular cleanser and a free radical scavenger. It detoxifies heavy metals and defends against damage from smoking, radiation and chemotherapy.

External
Vitamin A - vitamin A and its precursor beta carotene are powerful free radical scavengers.

Vitamin C - it has been proven time and time again that vitamin C is a powerful antioxidant. Vitamin C combined with bioflavonoid becomes even more potent. It also enhances the immune system and may recycle other antioxidants like vitamin E.

Vitamin E - is a powerful antioxidant as well, and prevents oxidation of lipids(oxidized LDL is responsible for hardening of arteries). It also improves oxygen utilization, enhances immunity, may be useful in preventing cataracts caused by free radicals and has a protective effect on the heart.

Minerals

Selenium - acts synergistically with vitamin E and may also increase vitamin E uptake.

Zinc - has antioxidant properties and is a constituent of superoxide dimutase (SOD). It may help keep vitamin E levels in blood and aid in absorption of vitamin A.

Semi essential antioxidants

CoQ10 - is an antioxidant that may play an important role in generation of cellular energy, immune system stimulation and also play a role in certain cardiovascular conditions. It may exert its' antioxidant effect by scavenging single oxygen.

Alphalipoic acid - may enhance the functioning of vitamin E, vitamin C and glutathione. It is both water-soluble and fat soluble therefore is also known as the "universal antioxidant".

Lutein - is found in vegetables like spinach and kale. It promotes long-term eye health in two ways. Lutein protects the eyes from damaging effects of the sun and as an antioxidant it protects the eyes from free radical damage and premature aging. The human body is unable to manufacture lutein, so the body must rely on lutein rich foods and supplements.

DHEA - is also called the "mother hormone", because it is the raw material for most steroid hormones produced in the body. It acts as an antioxidant and may be effective in preventing premature aging and stress.

Melatonin - may provide special protection to the nucleus within a cell, that contains DNA. It may stimulate the enzyme glutathione peroxidase. Also, used as a sleep aid.

To sum up:

Regular antioxidant intake may contribute to a longer and healthier life.

Antioxidants like superoxide dimutase(SOD) may also protect against hearing loss.

Vitamins A,C,E and melatonin may reduce age related degenerative diseases and slow the aging process.