|The Tracey Birnhak Nutritional Counseling Services|
|The Abramson Cancer Center of the University of Pennsylvania|
What are soy foods?
Examples of soy foods include: soybeans (also called edamame), soybean sprouts, tofu, soymilk and fermented soybeans (also called tempeh). These traditional soy foods have been used in many cultures as good sources of protein for thousands of years. More recently, processed soy protein has been added to a variety of foods, such as frozen meals, side dishes, soups, protein powder drinks, and snack bars.
Why worry about soy foods?
One of the many compounds found in soy is a plant chemical called isoflavone. Researchers like to study isoflavones because the shape of an isoflavone is similar in structure to estrogen and it is known to compete with estrogen in the body. Research about isoflavones has been confusing. Most studies show that eating traditional soy foods that have isoflavones may help reduce the risk of breast cancer and breast cancer recurrence. Unfortunately, some research has shown that very high amounts of processed or concentrated isoflavones can make breast cancer cells grow.
Should you eat soy foods?
*Processed soy food
Should you avoid processed soy foods?
Highly processed soy protein, or soy protein isolate, is used in many snack foods and vegetarian products. The isoflavones in these foods are very concentrated and may not be as safe as traditional soy foods.
Should you avoid soy supplements?
What about other soy products?
Should you avoid soy if you take an estrogen receptor antagonist such as Tamoxifen?
Still have questions? Talk with your doctor or dietitian.
If you are thinking about adding soy to your diet, it is important to consider:
Rock C, Doyle C, Denmark-Wahnefried, Meyerhardt J, Courneya K, Schwartz A, Bandara E, Hamilton K, Grant B, McCollough M, Byers T, Gansler T. Nutrition and Physical Activity During and After Cancer Treatment: An American Cancer Society Guide for Informed Choices. CA Cancer J Clin2012; 62: 242-274. Available at: http://onlinelibrary.wiley.com/doi/10.3322/caac.21142/pdf
For isoflavone content of foods: http://www.ars.usda.gov/SP2UserFiles/Place/12354500/Data/isoflav/Isoflav_R2.pdf
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