Antioxidants decrease the risk of vascular plaque formation and narrowing caused by LDL cholesterol by decreasing it's oxidation. It is the oxidized LDL that gets deposited in the vessel wall causing plaque formation. There is preliminary information to support vitamin E's positive effect in reducing the risk of coronary artery disease at doses of 400-800 mg per day. One epidemiological study actually showed an increased risk of death on people using vitamins A and C. Other studies have shown a protective effect. Maximum amounts of vitamin A should be 5,000-10,000 mg while beta carotene does not have a known toxic level.
Selenium is another anti-oxidant.
Dr. Kenneth Cooper suggests using selenium with vitamin E, vitamin C and beta-carotene to reduce the risk of heart disease. These vitamins can be obtained from fruits and vegetables, although some diets may be inadequate and supplementation may be desirable. See the VFS section on Vitamins and Minerals for more info. These substances are important in the breakdown of an amino acid called homocysteine. Homocysteine is now considered to be a vascular toxin that results in blockage of arteries, heart attacks and strokes.