Soy Foods and Breast Cancer Survival
An increased intake of isoflavone, the major phytoestrogen in soy, seems to correlate with a decrease in all-cause mortality in women with hormone receptor–negative breast cancer. Fang Zhang, MD, PhD, of the Friedman School of Nutrition Science and Policy at Tufts University in Boston, and colleagues published their study findings in Cancer. Soybeans and soy products are the richest sources of isoflavones in the human diet.
“Especially for women with hormone receptor–negative breast cancer, soy food products may potentially have a beneficial effect and increase survival,” commented Dr. Zhang in a press release from Tufts University.
A total of 6235 ethnically diverse women diagnosed with a first primary, invasive breast cancer completed the food frequency questionnaire analyzed in the study; 4769 women reported their dietary intake within 5 years before their breast cancer diagnosis, and 1466 women reported their dietary intake within 5 years after their diagnosis. The women were separated into quartiles based on their isoflavone intake.
Over a median follow-up of 9.4 years, 1224 deaths were documented. Those in the highest quartile of isoflavone intake (at least 1.5 mg daily) had a 21% decrease in all-cause mortality compared with those in the lowest quartile (less than 0.3 mg daily).