Sport & health

Páginas: 2 (400 palabras) Publicado: 22 de noviembre de 2010
Universidad Del Valle de Mexico
Free Radicals
Maria Cepeda Jordan
Sports & Health
November 23, 2009
They are atoms that have to do with cancer cells and aging. Free radicals are atoms orgroups of atoms with an odd number of electrons and can be formed when oxygen interacts with certain molecules. Once formed these highly reactive radicals can start a chain reaction, like dominoes. Theirchief danger comes from the damage they can do when they react with important cellular components such as DNA, or the cell membrane. Cells may function poorly or die if this occurs. To prevent freeradical damage the body has a defense system of antioxidants.
Antioxidants are molecules which can safely interact with free radicals and terminate the chain reaction before vital molecules aredamaged. Although there are several enzyme systems within the body that scavenge free radicals, the principle micronutrient (vitamin) antioxidants are vitamin E, beta-carotene, and vitamin C. Additionally,selenium, a trace metal that is required for proper function of one of the body's antioxidant enzyme systems, is sometimes included in this category. The body cannot manufacture these micronutrientsso they must be supplied in the diet.
Epidemiologic observations show lower cancer rates in people whose diets are rich in fruits and vegetables. This has lead to the theory that these diets containsubstances, possibly antioxidants, which protect against the development of cancer. There is currently intense scientific investigation into this topic. Thus far, none of the large, well designedstudies have shown that dietary supplementation with extra antioxidants reduces the risk of developing cancer. In fact one study demonstrated an increased risk of lung cancer in male smokers who tookantioxidants vs. male smoker who did not supplement. Whether this effect was from the antioxidants is unknown but it does raise the issue that antioxidants may be harmful under certain conditions....
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