Can soy increase the risk of breast cancer?

By Caribbean Medical News Staff
According to scientists at the Sloan Kettering Cancer Centre, soy products in the form of tofu, soy milk or other products may increase the rate at which breast cancer cells spread in the body with women who are already diagnosed with the disease.
That is an important distinction where once some scientists believed that soy products may increase the chances of breast cancer in women altogether.
“Although the genes were being expressed, it is not clear that this will translate into actual tumour growth. But the concern is that there may be the potential. Only 20 percent of those patients who took the soy had really high levels of the genistein metabolite,” said co-author of the study Jacqueline Bromberg.
According to the Study which was published in the September 4th Edition of The Journal of The Cancer Institute, between one week and 30 days of surgery to remove tumours, women were given soy protein powder containing genistein while the others received a placebo.
When compared by the researchers, the women who had taken the soy supplement after surgery, genes illustrated a change that suggested a propensity to promote cancerous cell growth.
The researchers compared tumour tissues from before and after the operation. In the women who had taken the soy supplement, changes were found in the expressions of certain genes that are known to promote cell growth.
Dr. Bromberg said that the reasons for the changes were inconclusive and required more investigation regarding causality and that the participants in the study had recently also had breast biopsies. They were also diagnosed with stage one or two breast cancer and were scheduled to have a mastectomy or lumpectomy within two to three weeks. Bromberg said it was difficult to determine that soy was the contributing factor to cancerous cell growth.
She also said that those women who consumed 51.6 grams of soy or the equivalent of about four cups of soy milk a day, had exhibited the changes in cell architecture and growth.
While the research did not illustrate how women could be affected who had not been diagnosed with cancer, the Study did warn women in Asia who often eat much soy in their diets, to be careful.