Although oxygen is essential for life, it can have adverse effects on your body. In the normal process of using oxygen, chemical changes occur that create reactive unstable oxygen molecules called free radicals, which can damage cells and structures within cells, including genetic material (DNA). Free radicals also may form in response to external factors such as cigarette smoke and alcohol, pollutants such as nitrogen oxide and ozone, and ultraviolet light and other forms of radiation, including X rays. If the genetic material in cells is affected by free radicals and not repaired, it can be replicated in new cells, contributing to cancer and other health problems. Free radicals may also weaken artery walls, allowing fatty deposits that can lead to heart disease to collect.
However, cells have special agents for combating free radicals and repairing molecular damage. These free-radical fighters are called antioxidants. A great deal of recent research suggests that antioxidants may play important roles in preventing or delaying heart disease, cancer, and other ills, and may even halt the damage to cells, thereby slowing the effects of aging. …….…click & see
Vitamins C and E are perhaps the best-known antioxidants. The mineral selenium is also an antioxidant, as are carotenoids such as beta-carotene and lycopene. Enzymes and certain other compounds (such as glutathione) manufactured by the cells themselves also function as antioxidants. Some experts now think that a number of other substances, including certain herbs, may act as antioxidants as well. For example, green tea, grape seed extract, and ginkgo biloba (among others) are all thought to have antioxidant properties.
Source:Your Guide to
Vitamins, Minerals, and Herbs