At the time most of these studies were done, few Western women were eating tofu, but many were getting soy without noticing it.

But there are no studies that have followed women long enough to solidify this.

We need to take into account that Asian women are more physically active, drink less alcohol, have children earlier, and their entire diet is different from Western women, all of which decrease their breast cancer risk.

At this point, women should not be taking high-dose soy supplements, especially those who are breast cancer survivors and women at increased risk for the disease. We don't have long-term data on the effects of these supplements, and there is some evidence that they could be harmful.

Given the complicated interplay of events and factors that go into developing cancer, we shouldn't be surprised that one food doesn't give us a clear signal. We shouldn't expect it to be so simple.

If women would like to hedge on the side that it may be protective, they should eat soy foods like soy milk, soy nuts and tofu.