As cells function normally in the body, they produce damaged molecules called free radicals. These free radicals are highly unstable and steal components from other cellular molecules, such as fat, protein, or DNA, thereby spreading the damage.
This damage continues in a chain reaction, and entire cells soon become damaged and die. This process is called peroxidation. Peroxidation is useful because it helps the body destroy cells that have outlived their usefulness and kills germs and parasites. However, peroxidation, when left unchecked, also destroys or damages healthy cells.
Antioxidants help prevent widespread cellular destruction by stabilizing free radicals. More important, antioxidants return to the surface of the cell to stabilize, rather than damage, other cellular components.
When there are not enough antioxidants to keep peroxidation in check, free radicals begin damaging healthy cells, which, in turn, can lead to problems. For example, free-radical damage to cells of the immune system can lead to an increased risk of infections.