Nutrition and Cancer - Phytochemicals, Antioxidants, and Omega-3 Fatty Acids

Nutrition to reduce cancer risk:

The scientific community is continually studying the role of diet in the development of cancer. Many results are preliminary and more is being learned every day. Research is discovering that intake of fruits, vegetables, and cereal grains may interfere with the process of developing cancer of the oral cavity, larynx, esophagus, stomach, colon, lung, prostate, and rectum. In addition to reducing the risk of developing cancer, the risk of developing heart disease, hypertension, obesity, diabetes, and other chronic diseases might also be prevented by eating more fruits and vegetables. There is also evidence that total fat intake of greater than 30 percent of total calories can increase the risk of developing some cancers. This is especially true when total fat intake includes saturated fat and possibly polyunsaturated fat. The Food Guide Pyramid, Dietary Guidelines for Americans, and 5 A Day for Better Health Campaign are good sources for nutritional information.

What foods help to prevent cancer?

Although research studies are inconclusive at this time, preliminary evidence suggests that some components of food may play a role in decreasing the risk of developing cancer, including phytochemicals, antioxidants, and omega-3 fatty acids.

What are phytochemicals (or phytonutrients)?

Phytochemicals are chemicals found in plants that protect plants against bacteria, viruses, and fungi. Eating large amounts of brightly colored fruits and vegetables (yellow, orange, red, green, white, blue, purple), whole grains/cereals, and beans containing phytochemicals may decrease the risk of developing certain cancers as well as diabetes, hypertension, and heart disease. The action of phytochemicals varies by color and type of the food. They may act as antioxidants or nutrient protectors, or prevent carcinogens (cancer causing agents) from forming.

What are specific sources of phytochemicals?

The list below is a partial list of phytochemicals found in foods:

  • Allicin is found in onions and garlic. Allicin blocks or eliminates certain toxins from bacteria and viruses.

  • Anthocyanins are found in red and blue fruits (such as raspberries and blueberries) and vegetables. They help to slow the aging process, protect against heart disease and tumors, prevent blood clots, and fight inflammation and allergies.

  • Biflavonoids are found in citrus fruits.

  • Carotenoids are found in dark yellow, orange, red, and deep green fruits and vegetables such as tomatoes, parsley, oranges, pink grapefruit, and spinach.

  • Flavonoids are found in fruits, vegetables, wine, green tea, onions, apples, kale, and beans.

  • Indoles are found in broccoli, bok choy, cabbage, kale, Brussel sprouts, and turnips (also known as "cruciferous" vegetables). They contain sulfur and activate agents that destroy cancer-causing chemicals.

  • Isoflavones are found in soybeans and soybean products.

  • Lignans are found in flaxseed and whole grain products.

  • Lutein is found in leafy green vegetables. It may prevent macular degeneration and cataracts as well as reduce the risk of heart disease and breast cancer.

  • Lycopene is found primarily in tomato products. When cooked, it appears to reduce the risk for cancer and heart attacks.

  • Phenolics are found in citrus fruits, fruit juices, dried and fresh plums, raisins, eggplant, cereals, legumes, and oilseeds. It is thought to be extremely powerful, and is studied for a variety of health benefits including slowing the aging process, protecting against heart disease and tumors, and fighting inflammation, allergies, and blood clots.

Phytochemicals generally cannot be found in supplements and are only present in food. Foods high in phytochemicals include the following:

  • broccoli

  • berries

  • soy nuts

  • pears

  • turnips

  • celery

  • carrots

  • spinach

  • olives

  • tomatoes

  • lentils

  • cantaloupe

  • garlic

  • apricots

  • onions

  • seeds

  • soybeans

  • green tea

  • apples

  • cabbage

  • Brussels sprouts

  • bok choy

  • kale

  • red wine

There is no recommended dietary allowance for phytochemicals. Eat a variety of foods, including plenty of fruits and vegetables, to ensure you are getting adequate amounts in your diet.

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