Dietary Soy After Breast Cancer

Last Modified: November 20, 2009


Dear OncoLink "Ask The Experts,"

I had an ER+ breast cancer that was treated 2 years ago. Is there any danger to eating soy products or other plant estrogens, like flax?


Karen Wagner MS, RD, LDN, Clinical dietitian specialist for the Abramson Cancer Center, responds:

The issue of soy and ER+ breast cancer is certainly confusing and we don't have all the information yet. At this time, the American Cancer Society and American Institute for Cancer Research have issued guidelines that say that about 2 servings of whole soy foods, one serving is equal to 3 ounces of tofu or tempeh, or 1/2 cup of soybeans, is safe. They do not recommend soy protein powders, or products with soy protein isolate. There are also many products that have soy oil, soy sauce, or soy lecithin, all of which are safe. At this time, flax is considered safe, as it does not have the same plant chemical as soy.

This question and answer was part of the OncoLink Brown Bag Chat Series, Understanding Breast Cancer Supportive Care Issues View the entire transcript.