“Oy Vey Soy! Exploring The Link Between Soy Foods & Cancer”

By: Alan Lee, RD, CDE, CDN, CFT


There seems to be so much confusion around the risks vs. the benefits of having soy foods as a part of healthy diet. How safe is soy for women concerned with breast cancer? How safe is soy for men concerned with prostate cancer? Is there any reason to avoid it in our diets? Are there health benefits of soy foods?


Soy For Men’s Health

Since soy foods contain phytoestrogens which are similar in structure to estrogen, some men avoid soy foods for fear of feminizing effects. Clinical studies show no effect of soy protein or isoflavones on sperm count, quality, or motility. They also do not impact testosterone or estrogen levels in men. There is no scientific evidence that soy foods cause feminizing effects in men. Soy food intake may lower the risk of prostate cancer! A meta-analysis in 2009 in the American Journal Of Clinical Nutrition showed that soy intake was linked to a 30% reduction in risk.


Soy For Women’s Health

According to the American Cancer Society and the American Institute For Cancer Research, daily moderate soy food intake does not increase breast cancer risk nor does it even increase a breast cancer survivor’s risk of reoccurrence.

In fact, there appears to be a small protective effect or no effect on breast cancer risk. Large scale studies of Asian women have found that those who eat soy regularly in fact have a lower breast cancer risk! Even though some animal studies suggest that the isoflavones (plant estrogen) (i.e. geinstein) may promote the growth of estrogen-positive tumors and decrease the effects of breast cancer medications such as tamoxifen. However, to be careful, supplements which have very high concentrations of isoflavones should be avoided.


Four (4) Reasons Soy Is Important For Healthy Living:


ONE – #1  – Soy is very nutritious and affordable. Soy protein is the only plant based protein that is considered a “complete” protein. Complete proteins contains all eight (8) essential amino acids which are typically found only from animal based proteins. One-half cup of cooked soybeans or edamame has 10-15 grams of protein. One cup of soymilk has 8 grams of protein.


TWO – #2 – In 1999, the Food and Drug Administration approved a health claim that diets containing more than 25 grams of soy protein per day may reduce the risk of heart disease.
Soy foods can lower cholesterol because they are low in saturated fat and high in fiber as well as other beneficial plant compounds. It can also modestly lower LDL (“bad”) cholesterol and provide an excellent alternative to other protein choices such as red meat.


THREE- #3 – Soy may help protect your bones. A recent study in post-menopausal Seventh Day Adventists found that drinking fortified soymilk – which contains similar amount of calcium and vitamin D as dairy milk – is linked with bone protection.


FOUR – #4 – Soy foods have a rich culinary history and are integral in Asian diets for more than 1,500 years. In Japan, the average citizen consumes 1-2 servings of soy products per day. A myth about soy is that the iron in soy foods is poorly absorbed. They provide a significant source of iron and are well absorbed in the body.


What does one (1) serving of soy food look like?

  • 1 cup of soy milk (plain or vanilla)
  • ½ cup of edamame (immature soybean in the pod)
  • 1 slice of tofu (3 ounces) – thickness of slice will depend on the firmess of tofu
  • 1 cup of soy yogurt
  • 1 soy burger patty (chicken-less vegetarian patty)
  • 1 scoop soy protein powder
  • ¼ cup dry roasted soynuts


  • Studies show that soyfood intake of up to three (3) servings is safe to consume and unlikely to have negative effects.
  • If you do not regularly enjoy soy products, then one of the easiest ways to introduce soy into your diet is to drink soymilk. Try Silk® Original Vanilla Soy Milk. It’s my personal favorite.


It may be in your best interest to consult with a Registered Dietitian (RD) who is culturally sensitive to your needs and can help you with customized recommendations based on their assessment of your nutritional goals and needs.


You can go to www.eatright.org to find a qualified nutrition professional in your area under “Find an Expert.”


About The Author:

Alan Lee, RD, CDE, CDN, CFT is available for nutrition counseling and education to members of The Eating Well Nutrition Program at TOUCH for people living with chronic illness. He has been the Registered Dietitian/Nutritionist at TOUCH since 2001.  He is a well-respected nutrition expert and has given presentations around the globe from London to Vancouver and the Caribbean. He did his dietetic internship at New York Presbyterian Hospital and graduated from New York University. You can also stay in touch with Alan via email anytime at AlanLeeRD@yahoo.com or by leaving at voicemail at (212) 229-2298.

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