Soy Foods and Cancer:
Soy foods and cancer is a hot topic. I got a lot of response from readers, listeners and clients on this topic!
The Facts About Soy and Hormones:
Most of the controversy over soy and cancer has to do with the fact that soy is one of the best sources of isoflavones, phytochemicals classified as phytoestrogens. A phytoestrogen is a plant chemical with a similar shape to estrogen, therefore allowing it to bind to estrogen receptors in the body.
This binding ability is why many people have heard that soy is bad for breast cancer, especially the type of breast cancer that grows in response to hormones. The truth is that no studies have proven that phytoestrogens cause cancer to grow; so far it is a theory.
The other side of the story is that many people think that a “balance” of hormones in the body is necessary for good health and therefore eating plant hormones can help “balance” and promote good hormones. There is no evidence for this theory other than most studies suggest a plant based diet is important for reducing risk of cancer.
What’s the Bottom Line?
When it comes to soy and cancer, there will always be people arguing on both sides of the issue. My take is that most plant foods have been proven beneficial to the body, including soy. Soy has been studied extensively in heart disease and is shown to benefit the heart.
What is most important with soy intake is that you get food forms of soy as opposed to processed pills and powders. Even for hormone receptor positive breast cancers, the most conservative medical professional would say that 3-4 servings per week is fine (FYI, a serving is 1 cup of soy milk or 1/2 cup soy beans or tofu).
Personally, I’m comfortable recommending up to 2 servings per day for hormone positive breast cancer survivors. The most important thing is to stay away from the soy powders (shakes, soy chips, soy breads, soy bars or soy supplements). The concentration of isoflavones is very high in these products and you’re also missing the other beneficial nutrients that come with whole soy.
More questions on this issue? Post a comment and I’ll be happy to respond.