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The Scoop on Soy

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The Scoop on Soy

Soy has been consumed worldwide over many centuries and is prevalent in the American diet. Despite its popularity, there is still criticism and confusion over whether soy is safe to consume. With more than 10,000 peer-reviewed studies since the 1990s to reference, let’s shed some light on the truths about soy.

Myth: Soy is not a good source of protein.

Truth: Soy is an excellent source of complete protein, containing all 9 essential amino acids. If you’re trying to eat a more plant-based diet, soy is a high-quality protein with an average of 7 to 15 grams per serving. A few common examples include:

  • Soy nuts (1/4 cup) contains 11 grams
  • Edamame (1/2 cup cooked) contains 11 grams
  • Tofu (3 oz. cooked) contains 9 grams
  • Soy milk (1 cup) contains 8 grams


Myth: Soy contains estrogen and may cause feminization in men.

Truth: Soy foods do not contain estrogen, but they do have isoflavones that are referred to as phytoestrogens (plant estrogens). They bind come estrogen receptors but do NOT act like estrogen. Consuming soy does not lower men’s testosterone levels or sperm count. Some clinical evidence suggests that soy may actually protect against prostate cancer.


Myth: You should avoid soy if you have a history of breast cancer.

Truth: The American Cancer Society says that it is safe to consume up to three serving of soy foods per day. Newer studies suggest consuming soy may help breast cancer patients after diagnosis. One serving is equal to one cup of soymilk, one ounce of soy nuts, and one-half cup of tofu, cooked soybeans and edamame. More research is needed on the effects of soy supplements.


Myth: Soy interferes with absorption of certain nutrients.

Truth: The plant properties in soy called phytates and oxalates should not reduce absorption of minerals like calcium and iron. Research strongly supports that calcium in soymilk is absorbed as well as cow’s milk. Some soy foods, such as firm tofu, contain high concentrations of iron that are also found to be well-absorbed by the body.


The moral of the story is the health benefits of soy trump the various concerns that surround it. As a general rule, try to choose whole soy foods such as soymilk, tempeh and tofu instead of the more processed soy in meatless dinner entrees and energy bars.  Enjoy soy!

For more information on nutrition consultations visit the Cooper Clinic Nutrition Services website or call 972.560.2655.

Article provided by Elana Paddock, RDN, LD, CDE at Cooper Clinic.