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Does Soy Really Cause Cancer?


"I avoid soy products because I heard somewhere that they can give you cancer". This is a very common concern we hear from clients, but is it true?

Soy products include foods such as soy milk, tofu, tempeh, and soybeans (otherwise known as edamame). They are an excellent source of protein, fibre, B vitamins, omega-3 fatty-acids, and iron. However, despite their nutritious value, soy products have gotten a bad reputation as being carcinogenic (cancer-causing), unhealthy, and/or unsafe. Let's get to the bottom of the research, and figure out the pros vs. cons of consuming soy products.

Where did the cancer-causing reputation come from?

Soy products naturally contain compounds called phytoestrogens, mainly in the form of isoflavones. These isoflavones closely resemble the hormone estrogen, and we know that excess estrogen is linked to an increased risk of breast cancer. So it does make sense that some people may be concerned about estrogen intake and an increased risk of breast cancer. However, there are a number of other foods that also contain estrogen-like compounds and these isoflavones only look like estrogen. Isoflavones actually have anti-estrogenic properties, which may lower the risk of certain cancers and may improve breast cancer outcomes.

What are the benefits of eating soy?

Reviewing the research, there is no correlation between consuming soy products and risk of breast cancer in women. Actually, women who consume soy products as part of a balanced diet may benefit from a protective effect against ovarian and breast cancers. There is also no evidenced correlation between consuming soy products and male infertility (decreased testosterone levels and/or semen production) in current research. In fact, men who include soy products as part of their diet tend to have a lower risk for prostate cancer.

Some benefits of eating soy include...

  • Lower risk of ovarian, breast, prostate, and other cancers

  • Improved bone health and bone density, and lower risk of bone fractures

  • Lower blood cholesterol and lower risk for cardiovascular disease

  • Some research indicates soy products can help reduce: skin wrinkles, depression, allergy risk, asthma, and COPD, as well as suppress the storage of abdominal fat

Are there any consequences to eating soy?

Like with anything, too much of a good thing can be a bad thing. It’s always important to maintain balance and variety as part of a healthy diet, and to not get carried away consuming a single food or nutrient. Dietitians of Canada recommends 2-3 servings of soy products per day can be enjoyed as part of a balanced, varied diet.

It may be of interest to some of our readers to mention that soybeans are one of the most commonly grown crops in North America and they are often genetically modified (GMO). Many people may be concerned about GMO products, however there is currently no research showing that GMO products are harmful to human health. If you are concerned about consumption of GMOs, you can choose organic soy products.

Other resources to explore

  1. Study from Japan: https://onlinelibrary.wiley.com/doi/pdf/10.1002/ijc.28088

  2. Dr. Greger: https://nutritionfacts.org/topics/soy/

  3. Academy of Nutrition & Dietetics: https://www.oncologynutrition.org/erfc/hot-topics/soy-and-breast-cancer/

  4. American Institute for Cancer Research: http://www.aicr.org/foods-that-fight-cancer/tab-content/soy-research-1.html

Want to learn more about how you can incorporate soy as part of a healthy, balanced diet? Book your appointment with Alex or Stephanie today!

#healthyeating #cancer #soy #cholesterol #hearthealth

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