Soy food associated with lower risk of death and breast cancer recurrence, says new study

September 06, 2015

"We found that women in the highest soy food intake groups had the lowest mortality and recurrence rates rate compared with women in the lowest soy food intake group, regardless of tamoxifen use status," said Shu.

The associations of soy food intake with mortality and recurrence were observed for women with either ER-positive or ER-negative breast cancer. The association between soy food intake and overall mortality did not appear to vary by menopausal status.

"It is important to note that we studied soy food intake and not the use of soy capsule supplements," explained Shu. "These capsules frequently contain only soy isoflavones, while soy foods contain other nutrients, as well. So we cannot infer that the isoflavones alone would provide the same protective benefits."

Soy isoflavones compete with estrogens in the binding of estrogen receptors, reduce estrogen synthesis and help clear steroids from the body. These anti-estrogenic effects may be one of the underlying mechanisms through which soy foods are associated with better breast cancer outcomes. Other constituents of soy foods, such as folate, protein, protease inhibitors, calcium or fiber, also may be responsible for the survival benefits of soy food consumption.

Source: JAMA