The Soy Ploy

soybeans

Today’s article about the dangers of soy products is from Nourishing Our Children, an organization dedicated to supported learning, behavior and health in children through optimal nutrition. I encourage all parents to visit their website and read the “What Parents Need to Know” section. There is also a downloads section with free guides and briefing books available for download.

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.

Long, slow fermentation (as in the traditional production of miso, tempeh and soy sauce) gets rid of the phytic acid and other digestive inhibitors but not the phytoestrogens in soy.

Myths About Isoflavones

One of the most common myths is that soy estrogens (isoflavones) are beneficial for your health. Isoflavones are the estrogen-like compounds occurring naturally in soy foods. They act as the plant’s natural pesticides, causing insects to become sterile. Research has shown that isoflavones can prevent ovulation and stimulate the growth of cancer cells. As little as 38 mg isoflavones per day (less than the amount found in 1 cup of soy milk) can result in hypothyroidism with symptoms of lethargy, constipation, weight gain and fatigue. The isoflavones in soy have been shown to cause reproductive problems, infertility, thyroid disease and liver disease in mice, rats, cheetahs, sturgeon, quail, sheep, pigs and marmoset monkeys.

Traditional Versus Modern Soy Foods

It is important to distinguish between traditional and modern soy foods. In Asia, traditional soy foods were consumed in small amounts, usually as a fermented condiment. Traditional fermented soy foods include miso, soy sauce, tempeh and natto. Tofu was prepared by a precipitation process that gets rid of some of the anti-nutrients, and tofu was often then fermented. Tofu was usually consumed in small amounts in fish broth, which provided lots of compensating minerals and compounds that support thyroid function.

Soymilk underwent a very long preparation process to get rid of anti-nutrients and it was consumed with shrimp or egg yolk, ingredients that helped compensate for the many anti-nutrients that remained. Mostly a food for the elderly, it was sometimes given to nursing mothers but never to growing children.

Problems with Soy Protein Isolate

Modern soy foods are very different. Most are made with soy protein isolate (SPI), which is a protein-rich powder extracted by an industrial process from the waste product of soy oil manufacturing. It is the industry’s way of making a profit on a waste product. The industry spent over 30 years and billions of dollars developing SPI.

Soy Protein Isolate is produced at very high temperatures and pressures. This processing does get rid of some of the anti-nutrients in soybeans, but unfortunately many of the proteins are denatured in the process, including lysine. That is why growing animals fed soy must be given a lysine supplement. In feeding studies, SPI caused many deficiencies in rats. That soy causes deficiencies in B12 and zinc is widely recognized; but the range of deficiencies was surprising.

Although SPI is added to many foods, it was never granted GRAS status, meaning “Generally Recognized as Safe”. The FDA only granted GRAS status to SPI for use as a binder in cardboard boxes. During the processing of soy, many additional toxins are formed, including nitrates (which are carcinogens) and a toxin called lysinoalanine. It was concerns about lysinoalanine in SPI that led the FDA to deny GRAS status for SPI as a food additive.

In spite of all these problems, SPI is the basic ingredient of soy infant formula and the FDA even allows a health claim for foods containing 6.25 grams SPI per serving.

The Dangers of Soy Infant Formula

Infants on soy formula can take in dangerously high levels of soy isoflavones. On a body weight basis, this can mean ten times the level that can cause thyroid suppression in adults after three months, and eight times the level that can cause hormonal changes in adults after just one month.

According to a Swiss report adult women consuming 100 mg isoflavones (about 2 cups of soy milk, or 1 cup of cooked mature soybeans) provide the <ahref=”http://www.westonaprice.org/soy/birthcontrolbabies.html”>estrogenic equivalent of a contraceptive pill.

This means for a baby that weighs 6 kg (or just over 13 pounds), 10 mg provides the estrogenic equivalent of a contraceptive pill. Thus, the average amount of soy-based formula taken in by a child provides the estrogenic equivalent of at least four birth control pills. Because babies are more vulnerable than adults to the effects of dietary estrogens, the effects could actually be much greater than that of four birth control pills.

Hence the statement, “Babies on soy formula receive the estrogenic equivalent of at least five birth control pills per day.”

Homemade Baby Formula

For adopted infants, or as a solution for mothers who aren’t physically able to breastfeed or who aren’t able to produce enough milk, we’d like parents to know that there are nutrient dense, homemade Baby Formula Recipes in the book Nourishing Traditions which have been used with great success by parents all over the world since 1995!

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Comments Join the Conversation

  1. Hudson says

    I don’t personally consume much soy but I find some facts in this article to be misleading, whereas I usually find Chris Kresser to be well informed and reasonable. In particular, I question the claim by the WAPF that soy is equivalent to birth control pills. Isoflavones can more properly be called estrogen modulators, with both pro- and anti-estrogenic effects depending on the tissue. Besides this, they have a totally different structure than human estrogen and synthetic BCPs, so to claim that “soy equals X number of birth control pills” is a bit silly as there is no way to know a) What their overall estrogen activity is, and b) What that would equate to in milligrams of synthetic estrogen. Many other plants do contain isoflavones, so “estrogen” is everywhere in our environment. Dairy is one food source that actually has been shown to increase blood levels of estrogen.

    Secondly, I have traveled throughout Asia and note that people eat a lot of soy. Now it could be that in the past they ate less, but everyone I talked to, from chefs to foodies to professors of cultural studies all agreed that historically they ate a lot of soy. Perhaps this was their cultural bias, but I think not. And anyway, with how toxic the WAPF makes soy out to be, you’d think the population of Asia would be closer to zero instead of 4 billion or whatever it currently is.

  2. dage says

    I have a PhD. in Biochemistry and currently a tenured associate professor at Ohio State University. I’d like to point out that this article is misleading and contains incorrect information. For example, Chris wrote: “This processing does get rid of some of the anti-nutrients in soybeans, but unfortunately many of the proteins are denatured in the process, including lysine. That is why growing animals fed soy must be given a lysine supplement.”

    The fact is, lysine is an amino acid, not a protein. Soy is naturally low in lysine (compare to milk and egg), an essential amino acid. This is the reason why additional lysine is added to animal feed. Also, proteins are denatured in all cooked foods. so there is nothing to be concerned about denaturation. In fact, proteins need to be denatured before they can be efficiently digested in your body.

    Chris also claimed that Asians eat soy products in small quantities and never gave soy milk to growing children. This is an absurd claim! Soy milk is widely consumed as part of the breakfast by the whole family throughout China. I know this because I am an immigrant from China.

    • Rafael says

      Besides the fact of lysine being an aminoacid and information about the nutrition in China, where I don´t live, do you have any other information regarding soy being a good or bad food choice?

    • Wout Mertens says

      Hi Dage,

      You are correct about the lysine, but that is only a minor point in the article. I’m more worried about the isoflavones etc. Do you find fault with the reasoning there?

      I found the wikipedia article on soy milk very interesting, http://en.wikipedia.org/wiki/Soy_milk , it seems that soy milk has been made for quite a while in China, although it apparently wasn’t fed to children according to http://en.wikipedia.org/wiki/Soy_milk#cite_note-5 .

      Another question, isn’t the degree of denaturation important in how digestible a protein is? E.g. lightly denatured proteins can be cut by proteases, whereas heavily denatured proteins are less digestible? So industrial soy milk might be less nutritious than traditional soy milk? (ignoring the additives)

      • dage says

        Hi Wout,

        I think there is sufficient evidence to show that isoflavone from food is safe for adults. Its supposed damage to infants is exaggerated by critics. Soy-based baby formula exist for a reason, i.e, to feed infants with lactose intolerance. It is irresponsible to advocate banning soy-based formula.

        I am not aware of any restrictions on soy milk usage in China. Not only soy milk, but also all kinds of tofu products (not just fermented ones!) are widely consumed in China and Japan. Immature soybean is also consumed as a delicacy in the form of edamame.

        To also answer Rafael’s comments, whether you live in China or not is irrelevant. Obviously if soy is that bad, how come the bad things haven’t happened to people living in the regions with widespread consumption of soy? This is a dilemma that Chris unfortunately chose to resolve with incorrect information.

        Finally, when you heat your food to the boiling point, proteins are all denatured. It is not true that half-denatured proteins are easier to digest. As long as you don’t burn your food, you don’t over-denature the proteins. In fact, slowly cooking meat causes proteins in connective tissues (such as collagen) to break down, aiding digestion. I don’t think that industrial soy proteins are heated at higher temperature than conventional cooking. In terms of digestibility, it is better than eating whole soybeans.

        Btw, I found that my earlier post actually contained an error. Soy proteins are not low in lysine. In fact soy is a complete protein with nutrition value equivalent to milk and egg. I was misled by Chris’ article. The main ingredient in animal feed is corn, which is deficient in lysine. This is the reason why lysine is added to animal feed. It has nothing whatsoever to do with the nutrition value of soybean meal.

        • Rafael says

          Hi Dage.

          I think there is sufficient evidence to show anything you want about soy and for me, that´s the problem.

          I´m not a PhD, nutritionist, doctor, not even linked to science, so I have to make my evaluation in a simpler way (maybe superficial to you): Why is soy consumption so controversial? Why so many scientists decide to attack the soy consumption on their studies? What do they gain doing that? Why soy?

          On the other hand, there´s a lot of money involved on defending soy. A whole industry. One of the biggest… I´ve read that many of the studies, that adverts the soy benefits, were sponsored or the authors are somehow linked to the soy industry and maybe that´s why some of the bad things caused by soy consumption are not widely reported. For each study showing harm, there is another one showing the benefits, and that causes… controversies. In a world where money is more important than public health, I prefer to be cautious.

          • dage says

            My original post was only meant to correct obvious mistakes in Chris’ article. Mistakes are very common in this kind of food advocacy articles. This is why I occasionally found myself having the urge to write some rebuttals, for what it’s worth. However, I know people can be passionate about their believes, so I have no expectation to persuade anybody. You of course are free to choose what to believe and what food to avoid. It’s none of my business. There is no tradition of soy consumption in this country anyways. Plus, avoiding soy is only inconvenient for vegetarians, particularly vegans, by losing out on such an excellent substitute of animal proteins.

            Soybean products had been widely consumed in East Asia long before the soy industry came to existence, I noticed that Chris studied Chinese medicine. A usual argument for Chinese medicine is that it has been used for hundreds of years so it must at least be safe. The same logic applies to soy. I wonder why there is a double standard.

  3. Caroline says

    This blog post is one of the most misleading and misinformed I’ve seen to date on the purported “soy controversy.” The overwhelming majority of research on soy intake and health strongly links soybean consumption to protection from heart disease, cancer, and cognitive decline in a predictable, dose-responsive manner. Any possible goitrogenic (read: thyroid-suppressing) effects of soy are easily curtailed through adequate iodine intake. The balance of existing evidence weighs heavily in favor of soybean consumption, including several well-established Cochrane Collaboration systematic reviews with pooled sample sizes in the millions, and a rigorous ranking of scientific research methods. Read the literature carefully, and you’ll find that those isolated studies that Kresser “cites” here, linking soy to possible negative health outcomes, were primarily performed in Asia, namely Indonesia, where the majority of soy consumed is as tofu which, in those respective countries, is preserved with formaldehyde. No wonder it was so heavily associated with health decline. I suggest Mr. Kresser pore through the literature with a fine-toothed comb before publishing ill-informed articles. To the readers of this post, I suggest you consult with Dr. Michael Greger, MD at http://www.nutritionfacts.org for more credible nutrition information.

  4. Russell says

    Comments such as:
    “The isoflavones in soy have been shown to cause reproductive problems, infertility, thyroid disease and liver disease in mice, rats, cheetahs, sturgeon, quail, sheep, pigs and marmoset monkeys.”

    MUST be cited. Shown by whom? I’m sick of reading advice on any side of the dietary debate that do not back themselves up. Without citations how am I to know where this information came from?

  5. Britt says

    Is the soy in multivitamins (e.g. Pure Encapsulations Nutrient 950 w/ vit K2) a concern?
    I do my best to stay away since it is a gluten cross reactive food that I am sensitive to.
    Just curious if it is not a problem when extracted from soy to make vit E in vitamins? I have not found any valid data for either side.

    The only good quality multivitamin that I can find that is soy free, etc. with Vit K2 and Folate. Is Dr. Ron’s Ultra Pure: Doc’s Best the next generation. It is a bit expensive.

  6. Wout Mertens says

    I just found this blog post explaining that moderate soy consumption is probably safe for post-cancer patients : http://www.naturalmedicinejournal.com/article_content.asp?article=377

    What strikes me is that the isoflavone dose they regard as safe and possibly beneficial is 10mg/day but that would mean 1/3rd cup? Odd. I also see that the only outcome studied is cancer, no mention of other health issues. It does note that soy consumption could be a proxy for a generally healthy diet.

    Another interesting bit is that rodents seem to process dietary isoflavones differently, it has worse effects for them vs humans. Possibly we’re adapted to higher isoflavone intake?

    Would love to read your thoughts on this.

  7. says

    Do you happen to know of any studies of, or know of a link between, soy’s role in coeliac (celiac) disease. I sometimes wonder if soy caused me to become intolerant to gluten. After all, gluten issues were uncommon before soy became so widely used in the food industry…

    • Bryan Mayo says

      I don’t know if soy would induce gluten intolerance, but I do know that wheat has changed quite a bit over the last 50 years. The wheat we eat today (at least in the US) has much more gluten than the ancient wheat varieties some humans have eaten for thousands of years. I’d bet that this new high-gluten wheat has more to do with the rise in celiac disease than soy.

      Bryan

    • Erik says

      I know someone who has celiac disease. He can’t eat most wheat products in the US but can eat most wheat products over in Europe, at least the places he went to in Europe, because the wheat there was from “heirloom” varieties which are low in gluten. The varieties that were bred and are mostly grown in the US are much higher in gluten content.

  8. Andrea says

    All processed foods are poison; no surprise there.

    Aren’t the diseases from soy linked to GMO soy?

  9. Melissa says

    Hello,
    I’ve been a vegetatian for almost 20 years (more than half my life) and started drinking soy milk 24 years ago, when it was 1st (commercially) available. I have stuck to the same brand my entire life. I have gone for annual bouts of 4 weeks & sometimes evena little longer, when I travel to the USA. I didn’t gain any weight from drdinking soy milk, neither did I lose any weight because I ‘rested’ from drinking soy milk. The brand I drink is high in calcium, iron & B12. Just like milk from a cow, not everyone may be able to handle soy, but for me, I definitely feel it’s the healthy fit for me.

    • admin says

      Hi Melissa,

      I’m not sure why you mentioned weight gain or weight loss in regards to consumption of soy milk. Soy is low in calories so it stands to reason that it wouldn’t cause weight gain. However, that doesn’t mean it’s a benign food at all.

      For more on the dangers of soy, see this article. You can also read The Whole Soy Story, by Kayla Daniel, Ph.D. The introduction is available online here.

      Chris

      • Rafael says

        Hi Chris,
        I think he linked the gain weight to thyroid dysfunction caused by soy intake. My mother and sister are vegetarian but unfortunately they are overweight/obese respectively.

  10. Mary says

    I’m trying to find out information for my daughter who recently is suffering from depression that is more than teenage angst. She’s been vegan for a year and a half and has lived on a diet very heavy in soy-based products. I’m suspecting that the soy is causing some of her depression. Is there anything out there that supports this?

    • says

      Not only the soy, but the deficiency in amino acids from animal protein. Low tryptophan = low serotonin. There’s no such thing as a healthy vegan. Try to convince her to at least try some eggs and cheese to begin with and see if she feels better… Good luck!

  11. says

    quite alarming all the weight gain and such. do you have any sources on that? i must be superman (or woman with all the estrogen in my body) considering i lost about 10 pounds of body weight with a slowed down thyroid gland.

  12. says

    Hi Mary,

    Welcome to the blog and thanks for your question.

    I plan to write a full post on this in the future, but in the meantime I can answer your question briefly.

    A vegan diet could absolutely be causing and/or exacerbating your daughter’s depression. There are several possible mechanisms depending on your daughter’s particular diet and circumstances:

    Overconsumption of soy inhibits endorphin production, is known to cause hormonal changes that affect mood and can trigger thyroid condition or worsen and existing thyroid condition, causing depression.

    B12 deficiency, which affects up to 80% of vegans.

    Iron deficiency, which is also very common amongst strict vegans.

    A deficiency of fat-soluble vitamins A, D & K2, which are found primarily in animal products.

    Not getting enough high-quality, easily assimilable protein.

    Eating too much sugar/carbohydrate. Vegans often have a sweet tooth, because they aren’t getting certain necessary nutrients from what they eat. I’m not just talking about white sugar, which most vegans avoid, but all concentrated sweeteners, fruit and simple carbohydrates.

    Too much polyunsaturated fat (vegetable oil). This is found in so-called “healthy” packaged snacks many vegans tend to eat, like vegan cookies.

    Lack of saturated fat and cholesterol in the diet. Both of these nutrients are essential to human health and play a significant role in regulating mood. Low-cholesterol, in particular, has repeatedly been linked to depression and suicidal behavior.

    You might want to check out my page on depression. It contains several links to articles I’ve written and other off-site resources. In particular, this post examines proper nutrition for preventing and healing depression.

    If your daughter is open to it, you might want to suggest that she visit this link, which dispels common myths about vegetarianism and points out some of the dangers of following a vegan diet.

    Hope this helps!

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