Soy foods may not be harmful to breast cancer survivors -- as some animal studies have suggested -- and they could even reduce the risk of recurrence of the disease, according to a study in the Journal of the American Medical Association, the Los Angeles Times reports. Breast cancer survivors have previously been told to avoid soy products in light of animal research showing that soy might increase the odds of a recurrence of the disease. Researchers had believed soy acts like the hormone estrogen, which promotes breast tumor growth. However, phytoestrogens, the elements found in soy and many other whole foods such as nuts, seed and other legumes, have virtually no estrogenic power. Instead, they take up the estrogen receptor sites and block the absorption of the cancer–causing xenoestrogens found in pesticides and plastics. Furthermore, phytoestrogens promote the conversion of women’s key estrogen, estradiol, to 2 hydroxyestrone, the anti-cancer estrogen metabolite created in by the liver as opposed to the 16 hydroxyestrone estrogen metabolite, which has long been considered a factor in all hormone-related cancers.  

The new study of more than 5,000 breast cancer survivors in China found that women who had the highest soy intake had a 29% lower risk of dying during the study period and a 32% lower risk of breast cancer recurrence than the women who had the lowest intake. Lead author Xiao Ou Shu, a professor of medicine at Vanderbilt University, said the issue has been controversial because some physicians have advised women to avoid soy, while others feel the foods are safe. "Our findings are important because nowadays, it's very difficult to avoid soy exposure," Shu said.

What could account for the difference in animal versus human studies? Women in China tend to eat traditionally prepared soy that is either fermented or cooked really well to make it more digestible and they are eating the whole food as nature intended. Animal studies tend to use components of the foods like the isoflavones, genistein or daidzein, studied by themselves. It becoming apparent the scientific model of studying an isolated element from the food fed to an animal does not provide the same results as a person consuming the whole food. As this complicated relationship between the chemicals and nutrients found in a whole food becomes better understood, it appears that all these elements work together to regulate the effect they have on the person. Studied in isolation, consuming any nutrient or chemical will produce a different result from eating the whole food.     

 Tips for Eating Soy:

1.    The best ways to consume soy are fermented such as miso, tempeh, black bean sauce or soy sauce, really well cooked like tofu, or in pod form like edamame.

2.    Look for Non-GMO-soy, preferable organic. Allergies to soy jumped 50% in Britain, after the introduction of GMO-soy into the marketplace.

3.    Avoid refined soy additives found in processed food.

4.    If preparing and cooking soybeans, ferment overnight by placing cooked beans in water with 1 tsp sea salt and 1-2 tablespoons apple cider vinegar. Rinse before using.

5.    Look for traditional recipes containing soy for the best health results

Coconut Chile Soup with Fermented Soybeans

Reference:

Portions of this article were reprinted with kind permission from http://www.nationalpartnership.org.  http://www.medicalnewstoday.com/articles/173715.php

Increased Urinary Excretion of 2-Hydroxyestrone but not 16a-Hydroxyestrone in Premenopausal Women during a Soya Diet Containing Isoflavones1                                                                                                               Lee-Jane W. Lu,2, Melanie Cree, Shalala Josyula, Manubai Nagamani, James J. Grady, and Karl E. Anderson, Departments of Preventive Medicine and Community Health [L-J. W. L., M. C., S. J., J. J. G., K. E. A.], and Obstetric and Gynecology [M. N.], The University of Texas Medical Branch, Galveston, Texas 77555 http://cancerres.aacrjournals.org/cgi/reprint/60/5/1299.pdf

Antiestrogen action of 2-hydroxyestrone on MCF-7 human breast cancer cells.                                                      J Schneider, M M Huh, H L Bradlow and J Fishman Abstract http://www.jbc.org/content/259/8/4840.abstract

Xenoestrogen modulation of the immune system: effects of dichlorodiphenyltrichloroethane (DDT) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).                                                                                                          Forawi HA, Tchounwou PB, McMurray RW. http://www.ncbi.nlm.nih.gov/pubmed/15186037

Xenoestrogens and Genetic Damage in Breast Cancer                                                                                                                                                                    Moire  Robertson Creek , Ph.D., MPH - SRI International http://www.cbcrp.org/research/PageGrant.asp?grant_id=43    

Seeds of Deception,  by Jeffrey Smith