Colorful Cancer Defense
Let vegetables in rainbow hues lead you to the pot of health gold.
Cancerphobia: You know a disease scares a lot of people when a new word is born of fear surrounding it. But you have more control over cancer risk than you realize. In fact, nearly half of all colon cancer cases and 38% of all breast cancer cases in the US are preventable through diet, exercise and weight management, according to a new report, Policy and Action for Cancer Prevention, published by the World Cancer Research Fund (www.wcrf.org) and the American Institute for Cancer Research (www.aicr.org).
“Eating a plant-based diet helps our immune system do its job,” says Kathy Allen, MA, RD, LD/N, CSO, nutritional therapy manager at Moffitt Cancer Center in Tampa, Florida. “Ideally two-thirds of your diet should come from plant sources in their natural form.”
Plant foods fight cancer development in several different ways, including acting as antioxidants. “Although oxygen performs vitally important function in the body, it’s a very unstable molecule,” says Neal Barnard, MD, nutrition researcher and adjunct associate professor of medicine at George
Washington University School of Medicine in Washington, DC. “During the course of normal chemical reactions that occur within our bodies, oxygen molecules can become damaged,” explains Barnard, who co-wrote The Cancer Survivor’s Guide (Healthy Living Publications). “When this happens, they become like piranhas, ready to attack cells that make up your internal organs or other parts of your body, including your DNA and chromosomes. They can then multiply out of control, which is the beginning of cancer.” Antioxidants act as shields to prevent damage from these unstable molecules.
Because they all work slightly differently, it’s best to eat a variety of antioxidant-rich foods, says Barnard. “Some antioxidants, including beta-carotene, work by protecting the cell membrane. Others, such as vitamin C, patrol the watery areas of the body, including the bloodstream. You need both.”
Pick a Rainbow
Use the five color categories of fruits and vegetables as a guide, recommends Astrid Pujari, MD, founder of the Pujari Center in Seattle, Washington. “This includes the red, yellow, orange, blue-purple and dark green. You want to eat seven servings (1 cup raw or 1/2 cup cooked) within this rainbow of colors every day.”
What are the substances that lie behind these protective colors? Beta-carotene is a yellow-orange pigment found in carrots, yams and cantaloupes. A precursor of vitamin A, 30 milligrams of beta-carotene a day (the amount found in two large carrots or one large yam) can help lower the risk of chronic diseases, according to Bernard. Dark green leafy vegetables such as kale also contain beta-carotene.
Lycopene, a cousin of beta-carotene, is a bright red pigment in tomatoes, watermelon and pink grapefruit. According to a study in the January/February 2007 issue of Nutrition and Cancer, men with the highest blood lycopene levels had a 55% drop in prostate cancer risk. (Pasta lovers, rejoice: Cooked lycopene, such as that found in tomato sauce, is more absorbable.) And anthocyanins, a group of compounds that give blueberries, cherries, plums and red cabbage their bright red and blue colors, are being researched for their potential anti-cancer benefits.
Cancer protection even comes in plain old green and white. “Broccoli, a cruciferous vegetable, contains sulforaphane, a compound that helps the body rid itself of toxic chemicals and carcinogens,” says Barnard.
The allium group of vegetables, including garlic, onions and their botanical relatives, may speed the elimination of carcinogens and block or inhibit the growth of cancer cells, particularly cancers of the colon and stomach (International Journal of Molecular Medicine 6/08). According to Bernard, studies with garlic in particular show that allicin, a compound responsible for garlic’s trademark odor, may reduce risk of stomach and colon cancer in those eating three to five cloves a day. Other antioxidants include vitamin E and selenium, found in beans, whole grains and nuts, and vitamin C, most abundant in red bell peppers, broccoli, Brussels sprouts, cantaloupe, guava, kiwi, oranges and strawberries.
Vegetable-derived fiber also does its cancer-fighting part by reducing the progression of hormone-dependent cancers such as breast cancer, which can be spurred by the female hormone estrogen. “The liver filters excess estrogen and sends it out with the waste,” explains Barnard. “Without fiber, the estrogen continues to circulate throughout the body.”
In addition to choosing foods that protect against cancer, it’s wise to avoid those that may sabotage your good-health efforts. “In general, meat tends to be associated with higher rates of colon cancer,” says Pujari. “Those eating red meat four times a week or more have a higher incidence of stomach cancer. If you do eat meat, cook it slowly, not at a high temperature, which is shown to produce carcinogens.” If you’re a carnivore by nature, choose organic or grass-fed varieties of meat.
Barnard, a vegan himself, suggests eliminating all animal proteins. “Beans should be the center of your diet,” he says. “Give yourself three weeks and make changes gradually. You’ll feel healthier and be better off for it.”
So don’t let the thought of cancer scare you. Employ the anti-cancer power of plants to reduce your risk.