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should we stay away from soy, after being told you have breast cancer?

Posted by ginasoftail

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There is some evidence from studies on soybean Isoflavones that it is okay and perhaps even beneficial for a person with breast cancer to consume soy products.

Here is an excerpt from


Isoflavones are found in soybeans, chick peas and other legumes. However, soybeans are unique because they have the highest concentration of these powerful compounds. Soy contains many individual isoflavones, but the most beneficial are genistein and daidzein.

Isoflavones show tremendous potential to fight disease on several fronts. They have been shown to help prevent the buildup of arterial plaque, which reduces the risk of coronary heart disease and stroke. Isoflavones may help reduce breast cancer by blocking the cancer-causing effects of human estrogen. They may also prevent prostate cancer by hindering cell growth. Isoflavones can fight osteoporosis by stimulating bone formation and inhibiting bone resorption. They may even relieve some menopausal symptoms as well.


Being a weak form of estrogen, isoflavones can compete at estrogen receptor sites, blocking the stronger version naturally produced by the body from exerting its full effect. Since high blood levels of estrogen are an established risk factor for breast cancer; weaker forms of estrogen may provide protection against this disease. Genistein has been found to hinder breast cancer as well as prostate cancer. Results from a new University of California study show that genistein slowed prostate cancer growth and caused prostate cancer cells to die. It acts against cancer cells in a way similar to many common cancer-treating drugs.

Actually, the latest studies show that genistein has been found to encourage breast cancer; so you should stay away from genistein, albeit not the "whole" soy products.
If the breast cancer that you have is hormonally positive (or sensitive) I would avoid soy.  If however it is hormone negative than I think the benefits of soy may outweigh the risks.  The problem is that if you have a hormonally positive cancer you will likely be trying to avoid estrogens as they are a fuel for your cancer. Soy acts as a mild estrogen which is what you have  been trying to avoid. As for genistein I agree with PJH.  I blogged about genistein last month, here is the link if you'd like to read it.
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