- Question from MoiraL: I have hormone receptor positive breast cancer and am using tamoxifen. Can I use soy products in my diet?
- Answers - Diana Dyer, M.S., R.D. I use soy products, and I had ER-positive breast cancer that was postmenopausal. I use soy products that are similar to traditional Japanese food products, such as tofu, tempeh, and miso soup. This is a controversial area, no doubt about it, and we don't have enough research in this area to actually demonstrate safety for women who have ER-positive breast cancer. However, there does not appear to be any substantial data in women showing harm after breast cancer, and the current recommendation is that an intake of soy products similar in quantity to an Asian diet is considered safe. As a personal aside, I have been consuming soy foods, 1-2 servings per day, for 11+ years without a recurrence. That's not a research study; that's just my own personal experience.
- Jennifer Sabol, M.D., F.A.C.S. I very much agree with Diana's opinions on this. While the phytoestrogens in soy may act like a very weak estrogen, it is most likely insignificant compared to the amounts that your body still produces, even if you are postmenopausal, and likely contributes very little to encouraging an estrogen-sensitive cancer to continue to grow. I think soy products as you would consume them in your diet are an excellent source of low-fat protein. I would not in particular go out of my way to consume concentrated processed soy tablets, thinking that it was going to do any good in terms of the cancer or your overall health, however.
- Diana Dyer, M.S., R.D. The term "phytoestrogen" is probably an unfortunate choice of terminology for this particular molecule under discussion because that molecule, which is called genistein, has so many other anti-cancer activities in the body. For example, it functions as an antioxidant, it helps with apoptosis (it encourages bad cells to die), and it's an antiangiogenic agent as well (it decreases the blood supply to a malignancy that is so vital for its growth). So in the overall context of food, it's very likely that all of these other activities of this molecule in our bodies are ultimately more important than whatever small estrogen effect it might have.
The Ask-the-Expert Online Conference called Eating and Drinking Through the Holidays featured Diana Dyer, M.S., R.D. and moderator Jennifer Sabol, M.D. answering your questions about how to stay healthy during the most hectic, high-calorie time of year.
Editor's Note: This conference took place in November 2006.
The materials presented in these conferences do not necessarily reflect the views of Breastcancer.org. A qualified healthcare professional should be consulted before using any therapeutic product or regimen discussed. All readers should verify all information and data before employing any therapies described here.
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