Antioxidant vitamins are used in a wide range of conditions where free radical damage is playing a role. Antioxidant vitamin combination is used in the prevention of coronary heart diseases, certain types of cancer, aging as well as free radical damage caused by excessive exercise, illness, certain medications, air pollution, smoke, radiation and pesticides. The main role of the antioxidant vitamins is as follows:
β carotene prevents free radical formation by quenching singlet oxygen, a highly reactive form of oxygen. Vitamin C is another free radical scavenger which deactivates free radicals. It works specially in the plasma, lung fluid, aqueous humour and interstitial fluid. It can increase white blood cell activity; play important roles in the biochemistry of antibodies, prostaglandin E 1 , B and T lymphocytes, and interferon. Vitamin E also scavenges free radicals in the blood along with β carotene and vitamin C. Moreover, vitamin E is essential to protect against some of the ill effects of smog and smoke. In relation to other nutrients vitamin E protects vitamin A from being destroyed in the body.
Dosage & Administration
β carotene is comparatively safe even at high and prolonged exposure. Individuals who routinely ingest large amounts of carotenoids can develop hypercarotenosis, which is characterised by a yellowish colouration of the skin and a very high concentration of carotenoids in the plasma. This benign condition, although resembling jaundice, gradually disappears upon correcting the excessive intake of carotenoids.
Vitamin C is generally a safe drug for human use in normal doses. Larger doses may lead to gastrointestinal tract upset and renal stone formation.
Vitamin E is considered safe even in large doses. Doses over 800 mg may cause diarrhoea, abdominal pain or cramps, fatigue and reduced resistance to bacterial infection and transiently raised blood pressure.