Case-control studies overall support a significant reduction in the risks of cancers of the esophagus, lung, stomach, and colorectum associated with both fruit and vegetables.
Breast cancer is associated with vegetables but not with fruit.
Bladder cancer is associated with fruit but not with vegetables.
The overall relative risk estimates from cohort studies suggest a protective effect of both fruit and vegetables for most cancer sites considered, but the risk reduction is significant only for cancers of the lung and bladder and only for fruit.
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.