Q. Is soy good or bad for an overweight breast cancer survivor? I’ve heard both.
A. Breast cancer survivors have sometimes been warned to avoid soy-based foods because of the natural estrogen-like compounds soy contains. A recent study of survivors from Shanghai, China, showed that is not necessary. In fact, women in this study who ate the most tofu, miso and other soy foods were less likely to experience a recurrence of their breast cancer than those who ate the least soy-based foods (Journal of the American Medical Association, Dec. 9, 2009).
Experts caution that this good news may not apply to supplements containing soy compounds such as genistein. You should be able to enjoy miso soup, tofu and tempeh without worry.

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  1. Bettye D.

    I have read that soy and fiber interfere with thyroid medicine. I take thyroid medicine first thing 30 minutes before I eat or drink anything. Then, I have soy milk and fiber with my cereal. Can I take thyroid medicine several hours after dinner (with no soy or fiber) and before bedtime?

  2. Jag

    There is a school of thought that believes frankensoy may interfere with thyroid hormones, and another camp that thinks thyroid dysfunction might contribute to cancer. Miso and tempeh or fermented soy products do not fall into the “avoid” category. There are tomes of evidence that foods can influence cancer. Read it and do what makes sense to you.

  3. alxzba

    re: soy products — you write that soy has proven ok (re: breast cancer) in a study of Asians — who evidently can consume soy products without GI problems. From what I have read, not so in Caucasians. Please address this as well. Thanks.

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