Soybeans - Friend or Foe?

Soy is one of those "wonder foods" that used to be sold only in health food stores or Asian markets in western countries.





In the last several years, soy has been showing up regularly on the shelves of mainstream grocery stores, packaged in an amazing variety of products and flavors. At the same time, a controversy has been brewing – is soy healthy or risky for breast cancer patients and survivors? Do soy foods protect you from cancer, or do they hasten its development?

Soybeans are a great source of the anticancer compounds known as isoflavones.   These isoflavones have powerful antioxidant properties, and may be able to prevent cell damage (oxidation) caused by free radicals.

Soy isoflavones can act like weak estrogens, and may block estrogen receptors, similar to the way that tamoxifen works to prevent a recurrence of estrogen-sensitive breast cancer.

Sounds great, doesn't it?  But there may be a problem of "too much of a good thing."  Just as an excess of natural estrogen may fuel the growth of a breast tumor, too much of the soy isoflavone genistein, in concentrated form in many over-the-counter nutritional supplements, may set the stage for tumor development.

While moderate consumption of soy-based products is very reasonable, some supplements extremely high in phytoestrogens, especially soy-based isoflavone compounds and flaxseed based lignans, have been promoted as "natural" treatments for hot flashes and other menopausal symptoms. Very well-designed clinical trials show these supplements are no more effective than placebo (sugar pills) at relieving these symptoms. There is good science to suggest these high dose supplements may have negative health effects.

The Bottom Line on Soy and Breast Cancer

You may get the most benefits from consuming soy isoflavones such as genistein, if the isoflavones come from food (sesame seeds, tofu, legumes)– not from nutritional supplements.

The American Cancer Society says that concentrated extracts of soy isoflavones may encourage tumor growth, and should be avoided. Women in the Japanese study who had the lowest rates of breast cancer had consumed soy from childhood, or at least from pre-puberty. Post-menopausal women should not overdo soy products, because the powerful isoflavones mimic natural estrogen, which fuels 80% of all cases of breast cancer.


  1. Barnes, S., et al.  "Soy Isoflavonoids and Cancer Prevention." Advances in Experimental Medicine & Biology  401.  (1996):  87-100.
  2. Barnes, Stephen.  "Anticancer Effects of Genistein."  The Journal of Nutrition  125  (1995):  777S-783S.
  3. Bergan, R., et al.  "Genistein-stimulated Adherence of Prostate Cancer Cells Is Associated with the Binding of Focal Adhesion Kinase to Beta-1-integrin."  Clinical & Experimental Mestastasis  14(4) (1996 Sept.):  389-398.
  4. Messina, M. J., et al.  "Soy Intake and Cancer Risk:  A Review of the In Vitro and in Vivo Data."  Nutrition & Cancer 21(2)  (1994):  113-131.


Flax Seeds - Benefits and Use

Flax seeds contain an omega-3 fatty acid known as linolenic acid (LNA). It is thought the LNA content in flax seeds slow the development of some cancers as well as increase the effectiveness of chemotherapy medication.   It decreases the inflammatory compounds that favor cancer development and suppress the immune system.

LNA is also thought to have a direct action on cancer cells, stopping their inability for apoptosis and ability for angiogenesis.

Flax seeds also serves as a leading source of lignans, phytoestrogens that influence the balance of estrogens in the body and help protect against breast cancer.Krups grinder amazon

Flax seeds must be ground fresh and used within 24 hours for their nutrients to be accessible.

An easy way to get flax seeds into your diet is by grinding a tablespoon in a coffee grinder or a mini food processor and adding it to cereal, oatmeal, or mix it in a fruit smoothie.


Do not heat the flax seeds because that will destroy the anti-cancer benefits. The omega-3 consumption that is derived from flax seeds is better complemented when omega-6 consumption is decreased (meat, eggs, and various vegetable oils).

Nutrient Analysis

Two tablespoons of ground flax seed provide 4g of fiber, including 2g soluble and 2g insoluble fiber.

Soluble fiber binds with water in the stomach, helping to delay stomach emptying time to make you feel full longer, and lowers cholesterol levels.

Insoluble fiber helps to promote bowel regularity and keep waste moving through the body to prevent constipation, per the American Heart Association.

Also, a 2 tablespoon serving of flax seed can provide about 3.5g of heart-healthy omega-3 fatty acids; 90 to 100 calories; 4g to 5g fat; 3g of protein; and lignans, phytochemicals shown to have antioxidant capabilities that which can help to lower your risk for cancers and heart disease.

Ways to Incorporate Flax in Your Diet

Try adding 1 or 2 tablespoons of ground flax seed to hot cereal, coconut or soy yogurt, applesauce, mashed sweet potatoes, gluten-free bread dough, muffin mixes, condiments and berry smoothies.

Flax seed oil can be drizzled over cooked vegetables, mixed in salad dressings, or even in soups.

Freshly ground flax seeds can be used as a substitute for the fat in a recipe. If a recipe calls for eggs, you can use 1 tablespoon ground flax seeds mixed with 3 tablespoons of water to replace each egg.

Remember that you are increasing your fiber intake when you eat more flax, so it's important to drink enough fluids to avoid constipation.

~ Cheers!