Although recent research on antioxidants has yielded conflicting results, there is no doubt that eating a diet high in antioxidant-rich foods is healthy. Several studies link antioxidant-rich fruits and vegetables to a lower risk of heart disease, cancer, and many other illnesses.

The cells in our body need a steady supply of oxygen to draw energy from digested food. But consuming oxygen comes with a price; it generates free radicals, unstable molecules that can damage healthy cells. Free radicals are highly reactive because they contain an unpaired electron. So these free radicals search for a molecule from which they can steal an electron. The molecule that has lot an electron then goes in search of another electron to satisfy its deficiency and sets off a chain reaction in the body that results in the creation of more free radicals. A molecule that has lost electrons in this manner is said to have been "oxidized."

Although all healthy cells produce small amounts of free radicals, there are a variety of other factors that can promote free-radical formation in the human body, such as radiation like x-rays, cigarette smoke, alcohol, and environmental pollutants. Excessive free radicals can damage DNA and other genetic material. The body's immune system seeks out and destroys these mutated cells, in much the same way as it eliminates invading   bacteria and other foreign organisms. This mechanism declines with age, however, and the body becomes more vulnerable to free-radical damage.

Antioxidants are molecules that interact with free radicals, and stabilize them so that they cannot damage the cell. Sciences identified hundreds of antioxidants in our foods, including vitamins C and E; selenium, beta carotene and lycopene which is found in tomatoes. There are other phytochemicals (chemicals derived from plants), such as polyphenols in tea and wine that have antioxidant properties.

If free radicals are not neutralized by antioxidants they can cause irreversible damage leading to cancer. Antioxidants also help prevent heart disease by blocking oxidation of LDL (low-density lipoprotein), the harmful cholesterol. It is actually oxidized cholesterol that damages arteries. There are hundreds of studies linking antioxidant-rich diets to a lower risk of both cancer and heart disease, as well as other degenerative diseases.

But the impact of antioxidants may not be all positive. In clinical trials that studied the effects of antioxidants supplements on cancer in the last decade, results ranged from a reduced incidence of gastric cancer, to a possible increase in lung cancer rate associated with antioxidant intake.

Researchers in Cleveland, USA found that vitamin E provided no benefits to people suffering from cardiovascular disease and that beta carotene supplements actually increased the risk slightly.

The data on antioxidants is mixed so far it may also be that the benefits of supplements only show up after many years. Results from ongoing clinical trials investigating the effect of antioxidant supplements on degenerative disease, should clarify the picture over  next few years what is known is that vitamin C (500 mg), vitamin E (400 IU), and beta carotene (25,000 IU), along with 80 mg of zinc and 2 mg of copper a day, can be of help in macular degeneration, a seri­ous eye disease.

On the other hand, according to medical trials, smokers who take high-dose beta carotene supplements actually increase their chances of developing lung cancer High doses of vitamin E, can interfere with blood clotting and increase the risk of a bleeding emergency. Some antioxidants may also reduce the effectiveness of the statin drugs, taken to reduce cholesterol levels. Ongoing studies continue to stress that everyone should get beneficial antioxidants the old-fashioned way-by eating their fruits and vegetables, not by taking extra supplements.

*   ORAC refers to the Oxygen Radical Absorbance Capacity, a test used to measure the total antioxidant power of foods.

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