Phytonutrients are natural compounds produced by plants for their protection. They help plants repel harmful insects, protect them from diseases, draught, ultraviolet rays, and pollutants. Until recently phytonutrients were not considered as important nutrients for humans; however, they are now thought to be necessary to sustain human life. Some examples of common phytonutrients are curcumin (which is an active component in turmeric), resveratrol (which is found in peanuts, pistachios, grapes, red and white wine, blueberries, and cocoa and dark chocolate), and quercetin (which is an active component present in red onions, apples, and peppers). It has been shown that several of these phytonutrients present in fruits and vegetables can reduce the incidence of chronic diseases such as diabetes, hypertension, atherosclerosis, and cancer.