Just as negative dietary and lifestyle choices can significantly increase the risk of cancer, evidence is mounting that appropriate food choices can be powerful tools in reducing risk and even defensive shields in preventing cancer. The American Cancer Society offers these four guidelines to reduce cancer risk:

• Choose most of the foods you eat from plant sources.
• Limit your intake of high-fat foods, particularly from animal sources.
• Be physically active: achieve and maintain a healthful weight
• Limit consumption of alcoholic beverages, if you drink at all.

The Society’s recommendations are consistent with the U.S. Department of Agriculture Food Guide Pyramid and the Dietary Guidelines for Americans. Although no diet can guarantee full protection against disease, the American Cancer Society believes that these recommendations offer the best nutrition information currently available to help reduce your risk of cancer.

Choose Most of the Foods

You Eat From Plant Sources Choosing foods from plant sources is vital to a healthful diet. Many scientific studies have shown that increased consumption of fruits, vegetables, and whole grains reduces the risk for cancers of the gastrointestinal and respiratory tracts and for lung cancer.

This reduction is one of the reasons foods of plant origin form the basis of the Food Guide Pyramid. Plant foods contain beneficial vitamins, minerals, fibers, and hundreds of other cancer-protective substances.

Although more research is needed to understand what specific properties or substances in plant foods may specifically protect against cancer, there are already many candidates under investigation—from vitamins and minerals to fiber and phytochemicals (including carotenoids, flavonoids, terpenes, sterols, indoles, and phenols).

Because the positive effects from these components may derive from the whole foods in which they are found, experts recommend food over supplements.

Antioxidants found in fruits and vegetables may help to prevent cancer. These are nutrients that seem to offer the body some protection against oxidation—damage done to tissue in the course of normal cellular function which may contribute to the effects of aging and to increased cancer risk.

Various antioxidant nutrients—including vitamin C, vitamin E, selenium, and carotenoids —may provide the body with some defense against cancer. Researchers are studying the protective role of antioxidants. Grains provide vitamins and minerals, such as folate, calcium, and selenium, which may also protect against cancer.

Whole grains are preferable to refined grains because they have more fiber and an abundance of certain vitamins and minerals. Beans and legumes are also good sources of nutrients that have cancer-protective qualities.

Although more research is needed to clarify the specific roles of these food components, there is still ample evidence to support eating 5 or more servings of fruits and vegetables a day (especially deep-green and dark-yellow to orange fruits and vegetables, those from the cabbage family, and legumes and soy products) and 6 to 11 servings of grains (with an emphasis on whole grains).

Limit High-Fat Foods, Particularly From Animal Sources

Decreasing the intake of high-fat foods, especially from animal sources, is very important. Studies show that people who eat a high-fat diet have increased rates of cancers of the colon, rectum, prostate, and endometrium (lining of the uterus).

Although these relationships exist, it is not clear whether they are due to the total amount of fat in the diet, to a particular kind of fat (saturated, monounsaturated, or polyunsaturated), or to another, unknown, factor.

Because fat, by weight, contains twice the number of calories than protein or carbohydrate, it is difficult to separate the effects of the fat from the effects of its calories. People who eat a high-fat diet are often heavier and tend to eat fewer fruits and vegetables, which also increases cancer risk.

Consumption of red meat, a major source of fat in the American diet, is linked to an increased cancer risk, particularly of the colon and prostate. Scientists are unable to determine whether the connection between red meat and cancer is due to total fat, saturated fat, or other compounds.

Meat contains compounds linked to cancer, such as heterocyclic amines, which are produced when it is cooked. This may be a link to colon cancer. Different fats (such as omega-3 fatty acids and vegetable oil) may have different effects on your risk of cancer.

Saturated fat is a particular concern for cancer risk and for coronary artery disease. How food is prepared is also important. Some cooking methods, such as baking, stewing, boiling, and poaching, are healthier ways than frying, broiling, or grilling.

Limit Consumption of Alcoholic Beverages

People who drink excessive amounts of alcohol have an increased risk of cancer, higher than that of the general population, especially cancer of the larynx, esophagus, stomach, and pancreas. There is no question that limiting alcohol consumption reduces cancer risk.

The risk of cancer begins to increase with an intake of as few as 2 drinks a day. Alcohol along with tobacco use produces a combined cancer risk that is greater than the sum of their individual effects. The risks for cancers of the mouth, throat, esophagus, and larynx are particularly increased.

Research also has noted a connection between alcohol consumption and an increased risk of breast cancer. Although the causes are not known, scientists speculate that alcohol may have a carcinogenic effect, perhaps reflected in its capacity to alter hormone levels. Drinking too much alcohol also may negatively affect eating habits.

The calories in alcohol—with little nutritional value—are perhaps being consumed in place of calories in healthier foods with cancer-protective values. A general rule: men should limit themselves to no more than 2 drinks a day, women to 1.