What is it? Overview Usage Side Effects and Warnings

What are Antioxidants?

Antioxidants are substances that inactivate free radicals, highly unstable molecules that can damage cell membranes and scramble the genetic information (DNA) in cells. Free radicals are produced in the body during normal cell metabolism, and at a higher rate following tissue injury or exposure to tobacco smoke, sunlight, X rays, and other environmental influences. To fight these dangerous chemicals, the body deploys a powerful antioxidant defense system, but it is hypothesized that in some cases the quantity of free radicals may overwhelm the body's natural defenses. This could theoretically accelerate or cause various illnesses.

Vitamins A , C , and E , beta-carotene , and the mineral selenium function as antioxidants,agents with the ability to...

In a 2008 detailed review of 67 randomized trials involving 232,550 participants, researchers found no evidence that antioxidant supplements could reduce mortality in either healthy or diseased individuals. On the contrary, there was some evidence that vitamin A , beta-carotene, and vitamin E supplementation may actually increase mortality.7

It is highly unlikely that antioxidants are harmful in modest quantities, such as those recommended by the U.S. government (called upper intake levels, or ULs). Foods that are naturally rich in antioxidants are considered not only safe, but beneficial. For more information, see side effects and warning information for the antioxidants that may help treat allergic rhinitis:

Vitamin C side effects and warnings

[Vitamin E side effects...