Antioxidants - substances that may prevent or delay some types of cell damage. Examples of antioxidants include beta-carotene, lutein, lycopene, selenium, vitamins A, C and E.
Vegetables and fruits are rich sources of antioxidants. There is good evidence that eating a diet with lots of vegetables and fruits is healthy and lowers risks of certain diseases. But it isn't clear whether this is because of the antioxidants, something else in the foods, or other factors. Most clinical studies of antioxidant supplements have not found them to provide substantial health benefits.