Doctors also say fruits and vegetables are rich in vitamins and minerals that function as antioxidants or cancer-fighting substances. Although the relationship of diet to cancer risk is very vague at this point, researchers recommend a diet high in fiber and low in fat with plenty of fresh fruits and vegetables, not vitamin supplements. You've most likely heard that fiber from fruits and vegetables is a vital part of any cancer preventive diet. Researchers have found that B folate, C and E act as anti-oxidants to fight free radicals, molecules that may damage cells and promote cancer. You can find vitamin C in citrus fruits, broccoli, cauliflower, brussels sprouts and baked potatoes.
Leafy greens contain E and B folate.
Beta Carotene and carotenoids. The human body uses beta carotene to manufacture vitamin A , and vitamin A deficiency has been linked to some cancers. As an overall nutritional component, carotenoids, of which beta carotene is one, are believed to help fight off cancer. Carrots, spinach, tomatoes, squash, watermelon, apricots, cantaloupe, papaya, mango and other dark green and deep yellow vegetables contain carotenoids, including plenty of beta carotene.