What are antioxidant vitamins?
Much research has recently focused on how antioxidant vitamins may reduce cardiovascular disease risk. Antioxidant vitamins — E, C and beta carotene (a form of vitamin A) — have potential health-promoting properties. Though the data are incomplete, up to 30 percent of Americans are taking some form of antioxidant supplement.
AHA Scientific Position
Green plants are full of antioxidants for good reason. They are especially vulnerable to oxidative stress since they produce pure oxygen during photosynthesis. To protect themselves they manufacture an assortment of potent antioxidants.
And so a hypothesis was born: dietary antioxidants are free-radical sponges that can stave off the diseases of old age. It was a great idea. “Putting two and two together, scientists assumed that these antioxidants were protective, and that taking them as supplements or in fortified foods should decrease oxidative damage and diminish disease,” says Halliwell, who pioneered research into free radicals and disease. “It was simple: we said free radicals are bad, antioxidants are good.”
The American Heart Association doesn’t recommend using antioxidant vitamin supplements until more complete data are available. We continue to recommend that people eat a variety of nutrient-rich foods daily from all the basic food groups.
Eating a variety of foods low in saturated fat, trans fat and cholesterol will provide a natural source of these vitamins, minerals and fiber.
Oxidation of low-density lipoprotein (LDL or “bad”) cholesterol is important in the development of fatty buildups in the arteries. This process, called atherosclerosis, can lead to heart attacks and strokes. Until recently, it was thought that LDL cholesterol lipoprotein oxidation and its biological effects could be prevented by using antioxidant supplements. However, more recent clinical trials have failed to demonstrate a beneficial effect of antioxidant supplements. Some studies even suggest that antioxidant supplement use could have harmful effects.
Using dietary supplements of antioxidants to prevent cardiovascular disease should not be recommended until their effect is proved in clinical trials that directly test their impact on CVD end points. Beneficial effects must be demonstrated in well designed (randomized, placebo-controlled) clinical trials before recommending widespread use to prevent cardiovascular disease.
At this time, the scientific evidence supports a diet high in food sources of antioxidants and other heart-protecting nutrients, such as fruits, vegetables, whole grains and nuts instead of antioxidant supplements to reduce risk of CVD.