In the American Cancer Society's book, Colorectal Cancer, Bernard Levin, MD, writes of the importance of filling your shopping basket with foods that help prevent colorectal cancer as well as other kinds of cancers.

"The key dietary strategy for preventing cancer of the large bowel is to increase your intake of fresh vegetables and fruits (especially vegetables) while lowering the amount of fat you eat," writes Dr. Levin, who chairs the ACS?s National Advisory Task Force on Colorectal Cancer and is vice president for cancer prevention at the University of Texas M.D. Anderson Cancer Center.

The evidence that eating vegetables prevents cancer ? including cancers of the colon and rectum, lung and prostate -- is building. Dr. Levin cites one report on more than 750,000 people who were studied for eight years. That report showed a significant decrease in colon cancer risk in men and women who ate lots of vegetables. When colorectal cancer does develop, eating cruciferous vegetables such as broccoli and cabbage can result in less serious cases of the disease, according to Dr. Levin.

Green leafy vegetables, such as cabbage and Brussels sprouts, are generally best for you. They offer large amounts of vitamins A and C and moderate amounts of B vitamins, potassium and iron.

Roots and bulbs, such as carrots, beets, onions and potatoes, are good sources of fiber, vitamin C, B vitamins and minerals such as potassium and magnesium. The stems and flowers group of veggies ? which includes broccoli, artichokes and celery ? gives you vitamins A, C and E as well as B vitamins, iron, calcium and potassium.

The legumes (beans and peas) provide a range of nutrients and contribute protein. However, they don?t provide everything you need for complete protein balance; whole-grain foods can provide that balance.

Folate and a related form of the vitamin called folic acid, which protect against colorectal cancer, are found in leafy vegetables, grains and legumes.

Fruits offer plenty of vitamins, especially vitamins A and C. They also give you minerals, other nutrients and fiber.

According to Dr. Levin, the best fruits for nutrition are berries, cantaloupes, mangos, persimmons, papayas and dried apricots.

Fruits break down into the following groups:

• Seed fruits including apples, cherries, peaches, pears, nectarines, grapes and others.
• Citrus fruits ? oranges, grapefruits and lemons.
• Melons such as honeydew, watermelon and cantaloupe.
• Tropical fruits, including kiwi, papaya and pineapple.

Wheat, rice, oats and corn are among the most widely used and well-known grains. Grains are the basis for flour, breads and cereals. But Dr. Levin points out that modern food processing often takes away the healthy properties from grain. The process of making white flour, for example, strips the outer hull, or bran, from the wheat kernel and takes away the inner part of the kernel called the germ. This is done to make dough rise better and remain fresher longer, but bran is a source of fiber, and the germ contains important nutrients. Because of this, it?s better to eat flours, breads and pastas made with whole grain, according to Dr. Levin?s book.

Processing robs rice of its nutrients as well. All rice begins as brown rice. It?s processed to peel away the outer hull, leaving it white. Brown rice is much more nutritious than white.

To prevent colorectal cancer, your diet should include a variety of nutrients, high amounts of fiber and low levels of fat, according to Dr. Levin. "By increasing the amount of vegetables and fruit in your diet, and by choosing whole-grain products, you will significantly lower your risk of this disease," he writes.