The body benefits from a variety of different antioxidants. Vitamin C, vitamin E, and beta-carotene (a compound related to vitamin A) are the vitamin antioxidants. Oranges, grapefruit, strawberries, green peppers, broccoli, and tomatoes are rich in vitamin C. Carrots, apricots, squash, spinach, and other green leafy or yellow-orange fruits and vegetables are rich sources of beta-carotene. Vitamin E is found in dark-green leafy vegetables, nuts, and vegetable oils.
The mineral selenium is a component of antioxidant enzymes, so it acts as an antioxidant when combined with these special proteins. A number of natural compounds found in plant sources also have antioxidant activity, but these are neither vitamins nor minerals. Flavonoids, which are found in apples, tea, and onions, are an example. Red wine is also believed to contain a flavonoid antioxidant that may partly explain the protection from high rates of heart disease attributed to people in some Mediterranean countries.
Antioxidants protect against damage from free radicals either by preventing them from forming altogether or by destroying them once they have formed. Generally, vitamin antioxidants act as scavengers that intercept free radicals before they can interact with LDL cholesterol or other important cell compounds.
Additionally, there is growing evidence that inflammation in the arteries can cause plaque to rupture, triggering the formation of clots. It is a clot that may eventually plug an artery that has been narrowed by fatty plaques, thereby cutting off the supply of oxygen to a portion of the heart -- which may bring on a heart attack. Since free radicals can trigger an inflammatory response, it is possible that antioxidants may help control inflammation.
One particular concern with taking antioxidant supplements is their effect on cancer. Large clinical trials in the 1990s, mostly on beta-carotene, have shown inconsistent results. In 1994, a well-publicized study on Finnish male smokers found a higher incidence of lung cancer in men who took beta-carotene supplements, but in 1996, another large study of mostly nonsmoking doctors found no change in cancer rates among those who took beta-carotene supplements. A study on the effect of antioxidant supplements on the risk of prostate cancer is currently underway. Overall, it appears that the role of antioxidant supplements in cancer prevention is still unclear.
The rest of this article will give you the latest scientifically based information on the roles that certain vitamins, minerals, and antioxidants may play in modifying blood cholesterol and lowering the risk of heart disease. We'll start out with the role that the B vitamins might play for your heart, explained on the next page.