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The Truth About Soy

In January, I addressed one of the most frequently asked questions I hear when I tell people that I’m vegan: “Where do you get your protein?” As I mentioned in that post, there are many great plant sources of protein. The one that is most often the victim of flashy headlines that grab people’s attention but don’t tell the full story, is soy. Tofu, tempeh, miso, and edamame are all derived from soybeans.


Soybeans are native to East Asia but are grown across the world. Soy is second only to corn as the biggest crop in the United States, but most of it is not grown for human consumption. According to a blog on Food Revolution’s website “In the US each year, there are approximately 83 million metric tons of soybean grown on 75 million acres of land. For comparison, wheat covers about 50 million acres, while corn tops the charts with 90 million acres...More than 70% of the enormous amount of soy grown in the United States is fed to livestock.”


Soybeans are a great protein to include in your diet because they contain all nine essential amino acids. However, you may have been hesitant to consume soy due to one of the most commonly circulated myths that soy causes or promotes cancer.


seasoning edamame with salt

Let’s dive a bit deeper into this myth. Soy is believed to mimic the effects of the hormone estrogen (the scientific term for this is estrogenic). However, there have been conflicting conclusions, and some researchers have said that soy isoflavones possess both estrogenic and anti-estrogenic effects on breast cancer cells. The isoflavones in soy bind to only one type of estrogen receptor (not both types as estrogen does), which means soy can reduce estrogenic activity. The Oncology Practice Group of the Academy of Nutrition and Dietetics tells us: “Emerging research suggests that soy foods may decrease the likelihood of breast cancer recurrence in women with a history of the disease.”


Also, consider this – people who live in the Blue Zone of Okinawa, Japan eat a lot of soy, yet are among the healthiest people in the world with one of the world’s highest life expectancies as demonstrated by the Okinawa Centenarian Study. This 25-year study sponsored by the Japanese Ministry of Health, Labour, and Welfare showed that “Compared to North Americans, they have a staggering 80% less breast cancer and prostate cancer — and less than half the ovarian cancer and colon cancer.”


Another myth you may have heard is that soy inhibits thyroid function. However, a closer look at the 2002 paper written about this risk factor uncovered that the damage to thyroid function was most likely associated with iodine deficiency rather than soy consumption. As long as your diet includes an adequate amount of iodine, soy consumption does not affect the thyroid hormones.


Soy has several health benefits, including protecting your heart health. “In a study published in 2020 in the American Heart Association journal Circulation, researchers examined data from 200,000 people and found that eating at least one serving of tofu per week was linked to an 18% lower risk of heart disease compared to those who rarely ate tofu.” Soy helps to decrease LDL (‘bad”) cholesterol levels, raise HDL (“good”) cholesterol levels, and lower blood pressure – all good things for your heart.


There are a couple of things to be aware of when choosing to consume soy. Soy is one of the top eight allergens that must be identified on food labels. If you have a soy allergy, then you should avoid it. Unfortunately, in 2018 in the U.S. 94% of soybeans were genetically engineered, so choose organic or non-GMO certified soy to avoid soy that has been sprayed with glyphosate.


As with any food, the best ones are those that are whole or minimally processed. When it comes to soy, those items are soybeans, edamame, and fermented soy foods (tempeh, miso, and tamari). When purchasing tofu, be sure to buy organic or non-GMO. If you are new to using soy products, check out a couple of my favorite recipes from Purple Carrot: Coconut Tofu and Kale Caesar with Tempeh Bacon (skip the step with liquid smoke by buying smoky tempeh strips). Plain tempeh is great tossed with buffalo or BBQ sauce. Enjoy!

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