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Is Soy Safe?

Great source of nutrition

Soy has long been recognized as a nutrient-dense food and as an excellent source of protein by respected dietitians and clinical nutritionists. The soybean contains all the essential amino acids, as well as an impressive list of micronutrients such as calcium, iron, magnesium, manganese, phosphorus, potassium, B vitamins and zinc. Soy is also a source of fibre and omega-3 and 6 fatty acids. The nutrient content varies among products, but is in the highest in whole soy foods such as edamame (whole soy beans), soy milk, tofu and tempeh.

False information abounds

Yet despite the powerful health benefits of whole soy foods, myths and misinformation regarding the “dangers” of soy consumption are widely circulated and presented as fact by self-proclaimed “health experts”. Here’s a closer look at the sources of confusion and controversy - from a professional, licensed nutritionist).

All soy is GMO!

Let’s remember that the biggest consumers of commercially grown GMO soybeans in the world are farmed animals. GMOs are genetically modified organisms, and their safety for human consumption is a hot topic of debate. Many European countries have banned them. While conclusive data on the long-term health effects of GMOs is lacking, GMOs are everywhere in our food supply and soybeans are one of the major reasons. Currently, 81% of the global soybean crop is genetically modified, and approximately 85% of all GMO soybeans end up in farmed animal feed. The GMO soy consumed by farmed animals does not just magically evaporate in the slaughterhouse or the milk processing plant. It ends up on your plate.

But while an alarming percentage of soybeans are genetically modified, not all soy is GMO. Of the soy directly consumed by humans, non-GMO soy foods such as tofu, tempeh and soy milk are widely available in stores which offer soy products, and they are clearly labeled non-GMO.

But soy causes cancer!

Misinformation regarding soy’s relationship to cancer largely stems from confusion around the phytoestrogens in soy. Phytoestrogen is not the same thing as estrogen. Estrogen and testosterone are steroid hormones, and occur naturally in both sexes of humans, as well as in animals used for food. They help regulate sexual function and secondary sexual characteristics, in addition to nonsexual cellular functions. While estrogen plays many important beneficial roles in humans, it also naturally promotes proliferation of cells, and, at high levels, can increase risk of some cancers by encouraging cells to multiply more than they usually would. Hormone replacement therapy in postmenopausal women has also been implicated in cancer growth.

Soy does not contain estrogen, but animal foods do!

Many consumers are aware that animals used for meat and dairy are commonly supplemented with synthetic growth hormones, but what they don’t consider is that animal flesh and cow milk also contain their own naturally occurring estrogen— and this is true even of “grass-fed” and “organic” animals. Furthermore, meat, dairy and eggs all contain phytoestrogens; they are pervasive in our food, both plant and animal-derived. You can’t avoid them completely by avoiding soy.

Phytoestrogen is just a general term for numerous naturally occurring plant compounds which are similar in structure to mammalian estrogen. They can weakly mimic estrogen or block its effects. The concern over soy and cancer stems from the fact that soy-based foods contain phytoestrogens (specifically, isoflavones) and these react with the estrogen receptor. However, isoflavones do not have the estrogenic effect of inducing tumour growth.  

Soy protects against hormone-dependent cancers

The inverse relationship between soy consumption and risk of developing premenopausal breast cancer has been clearly established. In other words, higher rates of soy intake are associated with lower rates of breast cancer. Conducting large clinical trials on the effects of phytoestrogen consumption in cancer patients have not yet been conducted, but research has shown that soy protein shrinks tumours in animals. Obviously, we are not mice and it is dangerous to draw comparisons between humans and lab animals. It makes more sense to focus our attention on the already available mass of epidemiological studies which compare Asian cultures to those consuming a Western diet.

Lessons from Asia

Soy has been a major staple in Asian cultures for centuries, and their incidence of heart disease, cancers, osteoporosis, diabetes, and obesity are all much lower than what is seen here in the West. However, when these people begin to consume foods based more on the Western diet, not surprisingly, their patterns of disease begin to mimic ours as well, proving that how we live and what we eat has a huge and direct impact on our health, independent of the mass of genetic information all humans share.

The world’s highest known concentration of centenarians live in Okinawa. Regular physical activity, lean BMIs (body mass index), and high consumption of fruits, vegetables and soy are all a part of traditional Okinawan lifestyle. Their aging population enjoy healthier lives and much lower rates of cancer, dementia, osteoporosis, and coronary artery disease.

The myth of ‘moobs’ (man boobs)

“Moobs” is another heavily circulated myth with no actual basis in scientific fact. The “soy causes man boobs” urban myth is thus likely rooted in the confusion between estrogen and phytoestrogen, but, as previously explained, phytoestrogen is NOT estrogen. If indeed this were the case, there would be a lot of men in need of bras.

In reality, clinical studies in men show that isoflavones do not affect testosterone levels or circulating estrogen levels. Even at levels of isoflavone exposure significantly higher than those of a typical Asian male consuming a soy rich diet, isoflavones have not been found to have feminizing effects.

Soy hysteria and WAPF

Soy hysteria and the Weston A. Price Foundation (WAPF) are inseparable. Much of the fear-mongering around soy is a direct result of misinformation disseminated by the WAPF’s relentless anti-soy campaigns. The WAPF, registered as a nonprofit organization, is a multimillion dollar operation that lobbies for raw milk and grass-fed beef. Its members (often farmers) make financial contributions and in turn benefit from WAPF promotion. One of the WAPF’s ongoing strategies for promoting animal farming interests is a concerted effort to discredit veganism in general, and soy in particular. The soy industry is expanding exponentially, thus posing a potential threat to the products the WAPF are trying to peddle. In response, the Weston Price Foundation actively publishes articles which spread the supposed dangers of soy consumption, often citing bogus studies to appear credible.

What types of soy foods are healthiest?

In discussions of soyfoods, the assertion is sometimes made that only fermented soy foods are safe and healthful to consume, with the eating habits of traditional Asian cultures cited as support for this claim. In fact, contrary to this common misconception, the soy products regularly consumed in Asian countries are not all, or even primarily, fermented. In Japan, about half of soy consumption comes from the fermented foods miso and natto, and half comes from tofu and dried soybeans. In Shanghai, most of the soy foods consumed are unfermented, with tofu and soymilk making the biggest contributions. In fact, even in Indonesia, where tempeh is a revered national food, unfermented soy products like tofu account for around half of soy intake.

The bottom line

Personally, I enjoy a wide variety of healthy foods. I buy locally grown, seasonal produce from local market stalls. When possible, organic. When it comes to soy foods, I am always careful to buy non-GMO products, which are easy to find and are clearly labeled. Thai-style stir fry and tofu scramble are among my favorite tofu dishes; they are easy to prepare and can be made in one pan. I also season and bake firm tofu, then place it in a wrap for a quick lunch. In the winter months, I make creamy vegetable soups with a soy milk base, and grilled tempeh is great on sandwiches and crumbled over salads. If you’re looking for inspiration there are numerous websites and cookbooks which offer delicious soy recipes, ranging from super-easy to gourmet.

Whole soy foods are safe and nutritious. Include them in your diet along with a variety of fresh fruits and vegetables, grains and legumes.

For more advice on how soy foods can help with your immune health check out the Foodwise Immune Boost Plan at:


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