Antioxidants inhibit the oxidation of molecules. When oxidation occurs in the body it can damage cells, DNA and other structures, and also form free radicals that then go on to damage cells and other structures. An overload of free radicals can cause irreversible damage in the body, and leave to heart disease, liver disease and some cancers.

Antioxidants can prevent some of the damage caused by free radicals. Vitamins A, C, and E, and copper, zinc and selenium are all nutrients that also have antioxidant effects. Polyphenols, anthocyanins and other compounds in foods can also have an antioxidant effect.

Eating a diet containing a variety of fruit and vegetables should provide a range of antioxidants and their protective effect. Antioxidants in foods can also act as natural preservatives and prevent food spoilage.