Isoflavones in food associated with reduced mortality for women with some breast cancers

An epidemiological analysis of data from more than 6,000 American and Canadian women with breast cancer finds that post-diagnosis consumption of foods containing isoflavones—estrogen-like compounds primarily found in soy food—is associated with a 21 percent decrease in all-cause mortality. This decrease was seen only in women with hormone-receptor-negative tumors, and in women who were not treated with endocrine therapy such as tamoxifen.

The study, led by nutrition and cancer epidemiologist Fang Fang Zhang, M.D., Ph.D., from the Friedman School of Nutrition Science and Policy at Tufts University, was published March 6 in Cancer.

“At the population level, we see an association between isoflavone consumption and reduced risk of death in certain groups of women with breast cancer. Our results suggest, in specific circumstances, there may be a potential benefit to eating more soy foods as part of an overall healthy diet and lifestyle,” said Zhang, who is also the 2016-2017 Miriam E. Nelson Tisch Faculty Fellow at the Jonathan M. Tisch College of Civic Life and an adjunct scientist in nutritional epidemiology at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts.