Tuesday, June 26, 2012

Soy May Help PREVENT Breast Cancer

Many people, especially those who have had breast cancer, avoid soy because they have heard it contains phytoestrogens, chemicals that mimic estrogen. Estrogen has been linked with the progression of breast cancer. Soymilk, tofu, edamame, and other soy products do contain phytoestrogens, and in some lab studies, these do seem to promote the growth of breast cancer cells.

However, human studies have different results than in vitro research:

·      2008 University of California Study: American women who average 1 cup of soymilk or ½ cup tofu each day have a 30% lower risk of developing breast cancer compared to women who consumed little or no soy1
·      2010: Shanghai Breast Cancer Survival Study (>10,000 participants): Women who consumed > 15 grams of soy protein per day had a 30% lower risk of recurrence compared to women who ate <5 grams per day (one cup of soymilk= 7 g, 4 oz tofu= 9-10 grams). 2
·      Asian countries tend to consume high levels of soy and also have the lowest breast cancer risk.

Soy is a complete protein source, meaning it contains all the essential amino acids, so is nearly equivalent to animal meat in terms of quality. Studies suggest that in addition to breast cancer prevention, soy may help to prevent prostate and colon cancers. Moreover, soy has shown to lower LDLs, or the “bad” cholesterol, and the FDA asserts that 25 grams of soy protein per day (as part of a diet low in saturated fat and cholesterol) may reduce your risk of heart disease.

My Recommendations
·        Do include soy in your diet.
·        Choose minimally processed soy products (e.g: edamame, organic soymilk)
·        As with everything, keep your soy intake moderate. Don’t overdose on it and don’t go out of your way to avoid it (unless you are allergic!)

·        Visit my previous blogs about soy: http://kellyspantry.blogspot.com/search?q=soy

(includes: "I'm Soy Confused!" "PhytoeSTROGEN's, A little hormonal, yes, but immasculating? No!")

 1) Wu AH, Yu MC, Tseng CC, Pike MC. Epidemiology of soy exposures and breast cancer risk. Br J Cancer. 2008;98(1):9-14.
2) Shu XO, Zheng Y, Cai H, et al. Soy food intake and breast cancer survival. JAMA. 2009;302(22):2437-2443.
4) http://www.pcrm.org/health/health-topics/soy-and-your-health

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