A number of women and some men I’ve worked with are concerned about developing breast cancer; whether they have been diagnosed with the disease, are afraid of a recurrence, have someone in their family with the illness or have had a breast cancer scare. I can certainly understand their worry as there is so much inaccurate information one can find not only on the Internet but from their own medical doctor.
What many people don’t understand is that soy foods can be very beneficial to both the prevention or reoccurrence of the disease. In a lecture, Michael Greger, M.D. illustrates that soy contains phytoestrogens unlike estradiol, an estrogen we make in our body. We don’t want to raise our level of estradiol since it may increase our risk of breast cancer. The significance of this is that soy provides an anti-estrogenic effect and inhibits the growth promotion effects of estradiol. For example, eating a cup of soybeans can provide a meaningful barrier to estradiol receptor production.
Greger points out further that women in their fifties living in the U.S. have ten times more breast cancer than women in their fifties living in Japan as Japanese women tend to eat a fair amount of soy products. But don’t lose sight of the fact that it is not just genetic – Japanese women moving to our country, assimilating into our culture and adhering to a Western diet have experienced an increase in breast cancer.
It’s important to note that you should be eating organic soy. If it’s organic then it would not be a genetically modified product. Also, the soy you ingest should be whole soy such as tofu, tempeh, natto, edamame, miso or soy milk. In a newsletter, John McDougall, M.D points out that the controversy about eating soy is tied to consuming concentrated or isolated soy protein, such as soy protein bars and shakes. Eating isolated soy protein increases insulin-like growth factor 1 (IGF-1) which raises your risk for certain cancers. Also, eating 20 servings or more a day of whole soy can increase your IGF-1. Now to put this in the right perspective, eating meat increases your IGF-1 and when you consume dairy, IGF-1 is actually in the dairy. But on the other hand, eating one to five servings of a whole soy product can add tons of health value to your diet.