Eating fruits and vegetables is an important part of a healthy diet. They provide essential vitamins, minerals, and other nutritious elements to the body, including phytochemicals. Phytochemicals are compounds that protect plants against disease, and in some studies they have been found to protect humans against heart disease and cancer. Phytochemicals insulate cells from the damage caused by free radicals. Free radicals are toxic oxygen molecules that destroy cells and accelerate aging. Further research is being done to determine the effectiveness of phytochemicals on humans. Consult your physician or a registered dietitian if you have any questions about your diet. If you want more information about phytochemicals, check your local or college campus libraries.