Beans and Lentils Prevent Breast Cancer
By Maureen Williams, ND
Healthnotes Newswire (May 19, 2005)—Women who eat beans and lentils frequently have a significantly lower risk of developing breast cancer than women who seldom eat them, according to a study in the International Journal of Cancer (2005;114:628–33).
Breast cancer is the most common cancer and the second most common cause of cancer death in women. Many studies have examined the effects of specific dietary habits on the breast cancer risk and have found that diets high in fat (especially animal fat) and low in fiber have been linked to increased risk, while diets that include cold water fish (for example, salmon and tuna), lots of fruits and vegetables and other high-fiber foods might be protective. Some, but not all, studies have found that a vegetarian diet might be linked with a lower risk of breast cancer. Legumes, such as beans and lentils, are a major protein source in vegetarian diets. They are rich in some of the food components believed to protect against cancer, including antioxidants, fiber, and phytoestrogens. The possible breast cancer–protective effect of eating legumes has not been previously studied.
The current study used data from a large ongoing study known as the Nurses’ Health Study II, which is examining the associations between lifestyle factors and disease patterns in women. A total of 90,638 women between 26 and 46 years old who did not have cancer upon entering the study were monitored for breast cancer during eight years of the Nurses’ Health Study II. The women answered dietary questionnaires at the beginning of the analysis and after four years. These were used to estimate intake of flavonols, a family of chemicals that are widely found in plant foods and that are known to have antioxidant properties. The risk of breast cancer in women whose diets provided large amounts of flavonols was not different from the risk in women whose diets provided few flavonols; however, an analysis of the effects of individual foods that are especially rich in flavonols (tea, onions, apples, string beans, broccoli, green peppers, blueberries, and legumes) showed that foods from the legume family reduced the risk of breast cancer significantly. Women who ate beans or lentils two or more times per week had a 34% lower risk of breast cancer than women who ate them one or fewer times per month.
These findings suggest that women can reduce their risk of breast cancer by eating beans and lentils frequently. This beneficial effect may be due to their rich content of flavonols and fiber, or to some other, as yet unidentified, characteristic of beans and lentils. In addition, beans and lentils are good sources of protein and can replace some animal foods in the diet if they are combined with a grain to make a complete protein. Moreover, previous studies have shown that eating legumes may be effective for preventing and treating diabetes. Further research is needed to determine what aspects of beans and lentils are cancer-preventive. For now, frequently eating beans and lentils can be recommended for women who want to reduce their risk of breast cancer and generally increase the healthfulness of their diet.
Maureen Williams, ND, received her bachelor’s degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice in Quechee, VT, and does extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.
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