Ok, we’ve established that good health requires fueling our bodies with the right foods and avoiding those foods that harm our bodies. This is a pretty general statement and probably seems a little obvious. Except for the fact that most of us don’t actually know what is healthy or harmful any more. The so-called “healthy” foods we see advertised actually aren’t. We’re told to eat more grains, and yet wheat is one of the most damaging foods to the body. We’re also told that vegetable oils are a healthier option and yet these lead to inflammation and heart disease, unlike the healthy animal fats we’re told to avoid. And then there’s soy.

Over the last few decades the drastically unfounded fear of meat has brought about a huge move towards meat-substitutes of all kinds, the most popular of which are soy-based. Products like tofu and soy milk are always heavily marketed as “healthy protein alternatives”, and as a result many people (particularly vegetarians and vegans) incorporate these foods into their diets.

But are they so healthy?

“Although widely promoted as a health food, hundreds of studies link modern processed soy to malnutrition, digestive problems, thyroid dysfunction, cognitive decline, reproductive disorders, immune system breakdown, and even heart disease and cancer.
How could soy be linked to all this disease? Because the soybean contains many naturally occurring toxins. All legumes contain toxins but the problem with soy is that the toxins are found in very high levels and are resistant to the traditional ways of getting rid of them.” Chris Kresser

These toxins, also called phytates bind to minerals like zinc, calcium, iron and magnesium and make them unavailable to the body. This alone, makes soy a particularly bad source of calories, but this is only one of the compounds that make it detrimental to health. Soy also contains compounds called phytoestrogens (or isoflavones) which mimic the effects of estrogen in the body.

In traditional societies a long, slow fermentation was used in the production of miso, tempeh and soy sauce, and this process mitigates some of the phytic acid and other digestive inhibitors in modern soy, but it has no effect on the phytoestrogens (isoflavones).

So what are Isoflavones?

Isoflavones (also known as soy estrogens) are estrogen-like compounds found in soy foods. These are part of the plant’s natural defense system (its own personal pesticide, if you will) that work by causing sterility in insects. In human beings, research shows that isoflavones can prevent ovulation and stimulate the growth of cancer cells. Even small amounts of these compounds can also cause hypothyroidism, lethargy, constipation, weight gain and fatigue. In animals, they have been shown to cause thyroid disease, liver disease and infertility, amongst other conditions.
According to a Swiss study, adults consuming 2 cups of soy milk, or 1 cup of cooked soybeans (100mg isoflavones) provide the estrogenic equivalent of the contraceptive pill.

How does this effect us?

Women: abnormally high levels of estrogen is disruptive to the menstrual cycle, can cause infertility and increases the risk of breast cancer.

Men: estrogen throws off the balance of estrogen to testosterone in men, leading to a lower libido, fat accumulation around the abdomen, loss of energy, stamina and virility and the development of man-boobs. A 2008 study at the Harvard Public School of Health also showed that men who consumed the equivalent of one cup of soy milk per day had a 50% lower sperm count than men who didn’t eat soy. Fun.

man-boobs anyone?

Man-boobs anyone?

Babies fed soy-based formula have 13,000 to 22,000 times more estrogen compounds in their blood than babies fed milk-based formula. Infants exclusively fed soy formula receive the estrogenic equivalent (based on body weight) of at least five birth control pills per day.(See article link below).

But haven’t soy products always been eaten in large quantities in Asia?

This is one of the first arguments people use to justify including soy in their diets, but it is unfortunately not true. Contrary to popular belief, traditional soy foods in these countries were eating in small amounts (between 10-60g in China and Japan), and were prepared using techniques of precipitation and fermentation which mitigated a lot of the negative compounds. Tofu was only eaten in small amounts, mostly as a part of a fish broth, which compensated for the anti-nutrient effects by providing plenty of minerals and compounds that support thyroid function. Soy milk was also prepared in a very lengthy process that neutralized a lot of the anti-nutrients and was only consumed with shrimp or egg (again making up for the lost nutrients). It was also never given to growing children.

Modern soy foods are very different, however. They are mostly made using a soy protein isolate (SPI), which is a protein-rich powder extracted industrially as a waste-product of soybean oil production. Kinda off-putting right? It is produced at very high temperatures which actually denatures many of the proteins. Not only that, but during this processing many additional toxins are formed, including one called lysinoalanine, which actually led to the FDA denying SPI a GRAS (Generally Recognized As Safe) status. And yet it is a basic ingredient of soy infant formula. Yikes.

The scary thing is that soy products are found in just about every packaged and processed food in the supermarket today. Even most chocolate contains soy lecithin. For this reason people are unaware how much of it they consume. It’s not just vegetarian tofu-lovers who are at risk here.

So, to summarize, here is a list of just some of the dangers of modern soy products:

  • Soy contains trypsin inhibitors that inhibit protein digestion and affect pancreatic function;
  • Soy contains phytic acid, which reduces absorption of minerals like calcium, magnesium, copper, iron and zinc;
  • Soy increases our requirement for vitamin D, which 50% of American are already deficient in;
  • Soy phytoestrogens disrupt endocrine function and have the potential to cause infertility and to promote breast cancer in adult women.
  • Vitamin B12 analogs in soy are not absorbed and actually increase the body’s requirement for B12;
  • Processing of soy protein results in the formation of toxic lysinoalanine and highly carcinogenic nitrosamines;
  • Free glutamic acid or MSG, a potent neurotoxin, is formed during soy food processing and additional amounts are added to many soy foods to mask soy’s unpleasant taste; and,
  • Soy can stimulate the growth of estrogen-dependent tumors and cause thyroid problems, especially in women.

    (list taken from http://chriskresser.com/9-steps-to-perfect-health-1-dont-eat-toxins)

    So next time you pause in front of the “Tofurkey”, “Soy Chikin” or soy “burgers” in the supermarket, consider reaching for real, unprocessed foods instead.

    For further reading on a more complete list on studies showing the negative effects of soy, click here.