Study: Soy Beverages Appear to Have Little Effect on Hot Flashes

Soy phytoestrogens may have little effect on the hot flashes experienced by postmenopausal women with breast cancer, according to researchers at the British Columbia Cancer Agency.

Hot flashes in women with breast cancer are worsened by chemotherapy and tamoxifen and/or the discontinuation of hormone replacement therapy.

Researchers studied the effectiveness of a soy beverage containing phytoestrogens as a treatment for hot flashes in postmenopausal women with breast cancer.

A randomized, placebo-controlled, double-blind study was conducted in postmenopausal women with moderate hot flashes who were previously treated for early-stage breast cancer. The women were given either a soy beverage containing 90 mg of isoflavones or a placebo rice beverage.

Researchers found no significant differences between the soy and placebo groups in the number of hot flashes recorded. However, both groups had a significant reduction in the number of hot flashes they experienced, probably due to a placebo effect, according to the study published in the Journal of Clinical Oncology.

Placebo effect is a beneficial effect that arises from the patient's expectations concerning the treatment rather than from the treatment itself.

Investigators concluded that the soy beverage did not alleviate hot flashes in women with breast cancer any more than drinking a placebo beverage. "Future research into other compounds is recommended to identify safe and effective therapies for hot flashes in breast cancer survivors," wrote the researchers.

Other Sources: Journal of Clinical Oncology