Free radicals are unpaired electrons that usually come from oxygen. The free radicals can cause damage to cells by causing a chain reaction of pairing and unpairing with atoms of cell membranes, breaking off new free radicals who try to pair with other atoms. This can cause catastrophic damage to cells, their proteins and subsequently, DNA. The most harmful oxidants are disarmed by a system of enzymes, but there are still oxidants that need electrons to be paired.
Antioxidants are chemicals which are stable with or without an extra electron. They can pair with free radicals into their electron cloud, ending the chain reaction.
Since DNA damage can cause cancer, free radicals that affect DNA are carcinogenic. Antioxidants may prevent this. According to one study, there is a correlation between DNA repair and switching from a meat diet and an all-vegetable diet.
Antioxidants, like vitamin E, have shown to be effective in protecting against cardiovascular diseases. Free radicals promote the formation of plaques in the arteries and veins of the body. Antioxidants can bind with the unpaired electrons in order to prevent this.
Foods with antioxidants can help the body rid of free radicals. A diet with sufficient amounts of vitamin E, vitamin C,h and beta-carotene (these act as antioxidants) would include fruits & vegetables such as oranges and carrots.