Reasons to take them: Rodents and insects fed a diet high in antioxidants outlive those on a regular regimen. The cells of long-lived strains of fruit flies and worms churn out greater quantities of their own antioxidants, such as superoxide dismutase (SOD), than do the cells of shorter-lived varieties. When researchers at Southern Methodist University placed genes that product extra antioxidants into fruit flies, the Franken-flies lived up to a third longer than normal insects and suffered less free-radical damage. As for humans, most studies suggest that an antioxidant-rich diet--lots of fruits and vegetables--helps protect against heart disease and cancer.
Causes for concern: Animals given extra antioxidants also tend to eat less, so part of the increase in longevity may be due to their low-call diet (see "Calorie Restriction"). In experiments where antioxidant vitamins like vitamin C were added to cell cultures, the cells responded by cutting back their own antioxidant production. Net gain: zilch. Taken alone, many antioxidants can actually create free radicals.
