vegetables 4Flavonoids are plant pigments that act as antioxidants, protecting the plant from the oxidative stress of photosynthesis. They act as antioxidants for humans who eat the plants as well. They protect cells from free radicals. A study appearing in the American Journal of Epidemiology (2007 165(5):514-523) looked at 1,434 subjects with breast cancer and 1,440 healthy controls. The researchers found that a higher intake of dietary flavonoids was associated with a lower risk of breast cancer.