Total fat and omega-3 fatty acids in the diet may reduce the risk of breast cancer. A new University of Minnesota study examined the effects of different levels of these substances on postmenopausal women. The study can be found in April's Nutrition & Metabolism.
High concentrations of estrogen in the blood and urine are associated with an increased risk of breast cancer in postmenopausal women. One hypothesis is that this increased risk is mediated by hormone metabolism, according to the article. Total fat and omega-3 fatty acids in the diet may affect breast cancer risk by altering estrogen metabolism, actually increasing the amount of estrogen the body metabolizes.
In a controlled, cross-over feeding trial, researchers gave 16 postmenopausal women three different diets, a high fat diet, a low fat diet and a low fat, high omega-3 diet for 8 weeks. Then they compared the hormone concentrations in their urine. Women who ate the low fat diet, and the the low fat, high omega-3 diet excreted the most estrogen. In the article, researchers concluded that “the results of this study indicate that urinary sex hormone metabolism was modestly altered in postmenopausal women by a low fat dietary intervention.”
Research conducted last year at the University of Guelph and published in the Journal of Nutritional Biochemistry suggested that a lifelong diet rich in omega-3 fatty acids may inhibit growth of breast cancer tumors by 30 per cent. A discussion of that research can be found here on newhope360.com and here on sciencedaily.com.