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Antioxidants

Posted by Blog Tuesday, March 29, 2011


Antioxidants neutralize the damaging effects of free radicals. Free radicals are molecules with unpaired electrons that steal electrons from stable molecules. The stable molecules can then become free radicals, causing a chain reaction of damage. Free radicals can damage artery walls and low density lipoproteins (LDL), increasing the risk of cardiovascular disease. Free radicals can also damage DNA, increasing the risk of cancer. A certain amount of free radicals is formed as unwanted byproducts of normal metabolism. Free radicals are also formed when hard radiation impacts living tissue. Pollution and cigarette smoke are two more
causes of free radicals.

Antioxidants can be found in foods. Also, the body produces antioxidants. The antioxidants produced by the body are dependent on certain nutrients to function. Vitamin C is one of the most powerful antioxidants. Vitamin C is found in fruits and vegetables. Like all good antioxidants, vitamin C can neutralize a free radical without becoming a free radical itself. Vitamin C can protect many indispensable molecules in the body, such as proteins, fats, carbohydrates, and nucleic acids (DNA and RNA), from damage by free radicals.

The protection of DNA from oxidative damage is one way that vitamin C can help reduce the risk of cancer. Vitamin C also has a role in recharging vitamin E and beta-carotene after they have performed their antioxidant functions. Iron is absorbed in the intestines with the help of vitamin C. Vitamin C assists the absorption of iron by protecting the iron from oxidation. If supplemental vitamin C is needed, the ascorbated form is easiest on the digestive system.

Vitamin E is a family of related antioxidants. Vitamin E is plentiful in raw nuts and seeds, especially sunflower seeds. Alpha-tocopherol is the main form of vitamin E. There are four tocopherols with proven antioxidant activity. There are also four tocotrienols in the vitamin E family with even stronger antioxidant activity.

These natural forms of vitamin E neutralize free radicals in the fatty areas of the body. Vitamin E reduces the risk of cardiovascular disease by protecting artery walls. Vitamin E is vitally important for the protection of the cell membranes from free radical damage. Unfortunately, only one of the eight forms of synthetic lphatocopherol is in a form that is found in nature. At least half of the forms of synthetic alpha-tocopherol are ineffective as antioxidants.

If supplemental vitamin E is needed, the natural form (d-alpha-tocopherol) with mixed tocopherols should have the best antioxidant activity. Beta-carotene is one of the most powerful antioxidants in food. No other form of vitamin A has antioxidant activity. Beta-carotene is plentiful in yellow and orange vegetables and fruits.

Green vegetables also are rich in beta-carotene. All of the many carotenes in food have antioxidant activity.
 One of the most powerful free radicals in the body is superoxide. Superoxide is neutralized with an enzyme made in the body that is called superoxide dismutase. Superoxide dismutase converts superoxide to hydrogen peroxide, a less dangerous free radical. There are three types of superoxide dismutase. Two types of superoxide dismutase use zinc for structural stability and copper for catalytic activity.

These two types of superoxide dismutase protect many areas including the red blood cells and the lungs. The third type of superoxide dismutase is found in the mitochondria and has manganese as its center. The body must have sufficient amounts of copper, zinc, and manganese for these important antioxidant systems to function.

An important free radical in the body is hydrogen peroxide. The body has an enzyme designed for the neutralization of hydrogen peroxide. This enzyme is called glutathione peroxidase. Selenium is part of this important antioxidant. Glutathione peroxidase protects against oxidation inside cells, in cell membranes with vitamin E, in blood plasma, in sperm, and in the intestines.

 Glutathione peroxidase has the ability to transform harmful antioxidants such as hydrogen peroxide into water. Glutathione peroxidase is then recharged with the assistance of the B vitamins riboflavin and niacin. The body must have sufficient amounts of selenium, riboflavin, and niacin to support the antioxidant activity of glutathione peroxidase.

Selenium is also found in another antioxidant, selenoprotein P. Selenoprotein P is capable of neutralizing nitrogen free radicals in the lining of blood vessels. Another mineral that is a necessary component of antioxidant enzymes is iron. These antioxidants can slow aging and reduce the risk of some chronic diseases.

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