What do antioxidants neutralize?

Antioxidants neutralize free radicals. More precisely, they reduce the damaging reactivity of free radicals and other reactive oxygen species that can attack cells.

Free radicals are unstable molecules or molecular fragments with an unpaired electron. They can arise naturally during metabolism and immune responses, and their production can increase after exposure to cigarette smoke, air pollution, ultraviolet radiation, or other stressors. In excess, they can contribute to oxidative stress and damage proteins, lipids, and DNA.

Many antioxidants work by donating an electron or hydrogen atom to a reactive molecule, stabilizing it without immediately creating another highly reactive compound. Important antioxidant defenses include vitamin C, vitamin E, glutathione, and enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. The body produces some antioxidants and obtains others through food.

A common misconception is that all antioxidant supplements are automatically beneficial. Antioxidants are essential components of normal biology, but high-dose supplements have not consistently been shown to prevent disease and can sometimes cause harm. A balanced diet rich in fruits, vegetables, and whole grains is generally a more reliable source.