Diet and cancer
Experts believe that more than half of human cancers may be preventable. Diet, as well as tobacco use, infections, and chemicals or hormones are thought to be major risk factors that can be changed. However, there is still little agreement over which dietary changes can prevent most cancers.
Fiber and cancer; Cancer and fiber; Nitrates and cancer; Cancer and nitrates
DIET AND CERTAIN CANCERS
Although a high-fat diet has been studied as a cause of breast cancer , no clear evidence has been found. A high-fat diet may promote breast cancer by causing the body to release more of certain hormones.
Because prostate cancer appears to be more common with a Western lifestyle, diet has been closely studied as a risk. However, results have not led to a clear answer:
- . Some studies have linked prostate cancer to a high-fat diet, especially including red meat and high-fat dairy products.
- . A diet rich in vegetables, fruits, and legumes appears to protect against prostate cancer . This may be because these foods are low in fat. No one vegetable or fruit has been proven to decrease the risk. Lycopene, which is found in tomatoes, has been investigated, but the evidence that it protects against prostate cancer has not been proven.
- . Major studies have found that vitamin and mineral supplements (vitamin E, vitamin C, vitamin D, and selenium) do not prevent prostate cancer.
- . A high intake of calcium has been linked to an increased risk for prostate cancer in some studies.
- A diet high in red and processed meats increases the risk for colorectal cancer . Diets high in fruits and vegetables appear to reduce the risk.
- Several major studies have found that eating a lot of high-fiber foods protects against colorectal cancer, but other studies show little benefit.
- It is also not clear whether a lack of certain vitamins, such as folic acid (a type of B vitamin), could increase the risk for colorectal cancer. Recent studies have shown that taking folic acid supplements does not lower the risk of getting colorectal cancer, and that supplements appear to increase the risk for polyps .
Countries in which people eat a lot of salt-cured, smoked, and nitrite-cured foods have a high rate of cancer of the stomach and esophagus. Examples of such foods include bacon, ham, hot dogs, and salt-cured fish.
The best advice is to eat a well-balanced diet and avoid focusing on one "cancer-fighting" food.
- Choose foods and portion sizes that promote a healthy weight.
- Choose whole grains instead of refined grain products to increase fiber in the diet (25 to 35 grams of fiber per day).
- Eat 5 or more servings of fruits and vegetables each day.
- Limit processed and red meat in your diet. Only eat salted, smoked, or cured foods on occasion.
- Limit alcohol to one drink per day (women who are at high risk for breast cancer should consider not drinking alcohol at all).
- Choose lean cuts of beef, lamb, and pork, as well as skinless poultry and fish. Baking, broiling, poaching, and steaming are the best cooking methods. Choose skim or low-fat milk and dairy products, as well as low-fat salad dressings.
- Dietary Guidelines for Americans
- The American Cancer Society is an excellent source of information on cancer prevention. www.cancer.org
- The American Dietetic Association provides sound dietary advice on a wide range of topics. www.eatright.org
- The National Cancer Institute's CancerNet is a government gateway to the latest, most accurate information on cancer prevention. www.cancer.gov
United States Department of Agriculture. Center for Nutrition Policy and Promotion. . 2010. National Academy Press, Washington, DC, 2010.
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