There have been differing opinions whether or not soy products prevent or cause breast cancer. Now, two major recent studies provide reassurance to women that soy is actually helpful, especially regarding recurrence.

This week’s Journal of the American Medical Association reviews a large 5,000 person Shanghai Breast Cancer Survival Study. In this study, women who had the most dietary intake of soy products had a 30% decrease in death and recurrence compared to those with the lowest intake of soy. There’s a nice review of the article in today’s LA Times. The LA Times also discusses how this encouraging finding was replicated in an American study earlier this year, using 2,000 breast cancer survivors and finding a similar benefit, even among those taking tamoxifen. There’s another synopsis of this important data here from Medscape.

The JAMA editorial sums it up well:

“Even though the findings by Shu et al suggest that consumption of soy foods among breast cancer patients is probably safe, studies in larger cohorts are required to understand the effects of these foods among diverse clinical subgroups of breast cancer patients and survivors. In the meantime, clinicians can advise their patients with breast cancer that soy foods are safe to eat and that these foods may offer some protective benefit for long-term health. Moreover, the potential benefits are confined to soy foods, and inferences should not be made about the risks or benefits of soy-containing dietary supplements.”