The Hidden Dangers of Soy




Alternative Medicine CategoryAs the American diet turns towards the perception of more natural and “healthy” foods, a surge in soy products has taken hold in the market. Soy is touted as a superfood full of protein, fiber, and antioxidants, and able to do everything from lower cholesterol to fight cancer. However, not all the physiological properties of soybeans are positive. Compared to the number of outlets proclaiming the benefits of soy, relatively few sources discuss the side effects of a soy-rich diet.

Unfermented soy products like soy milk and tofu form the bulk of American soy consumption. In Asian countries, which consume higher amounts of soy overall, the predominant form is fermented as found in soy sauce and miso. The fermentation process is significant because it removes much of the biologically active phylates and isoflavones from the soy.

SoyPhylates are a form of insoluble fiber, and in low quantities are beneficial because they can absorb low density lipoprotiens and therefore lower bad cholesterol levels. They are also known to reduce risks of gastrointestinal cancers. However, in higher quantities they can also block the absorption of other nutrients, leading to vitamin and mineral deficiencies. In particular, calcium, magnesium, copper, and zinc are prone to blockage by phylates, and this can paradoxically increase the risks of osteoporosis that soy is supposed to prevent.

Soy is purported to prevent osteoporosis because of its isoflavone content. Isoflavones are a collection of complex chemical compounds which are manufactured by plants, but physiologically similar to human proteins. One type of isoflavone found in large quantities in soy is called genistein, and in humans this protein binds with some affinity to estrogen receptors. This effect is what gives soy protein the ability to fight menopausal and premenstrual symptoms, and potentially prevent osteoporosis as mentioned above. On the contrary, overconsumption of genistein can lead to the same problems associated with high estrogen levels, namely increased risks of breast, uterine, and ovarian cancer. In males, the weak estrogen activity has translated into a reported reduction in the risk of prostate cancer. High intake has been suggested to suppress testicular cell lines, although this has not been proven. Perhaps the most widely accepted consequence of a high soy diet is an impact on thyroid function. Hypothyroidism and autoimmune disorders such as Hashimoto’s thyroiditis have been linked to excess soy intake in several animal studies.

Although the benefits of soy protein are well documented, no substance can be considered a panacea. Several problems can arise when soy is ingested in excess. Most dietitians recommend 25 grams of soy protein per day, and even the American Heart Association does not recommend exceeding 50 grams per day. The public would do well to adhere to these guidelines, to avoid any potential complications of soy toxicity.

References

R DIVI, H CHANG, D DOERGE (1997). Anti-Thyroid Isoflavones from Soybean Biochemical Pharmacology, 54 (10), 1087-1096 DOI: 10.1016/S0006-2952(97)00301-8

Kumi-Diaka J, Rodriguez R, Goudaze G. Influence of genistein (4′,5,7-trihydroxyisoflavone) on the growth and proliferation of testicular cell lines. Biol Cell. 1998 Jul;90(4):349-54.

M. Lakshman, L. Xu, V. Ananthanarayanan, J. Cooper, C. H. Takimoto, I. Helenowski, J. C. Pelling, R. C. Bergan (2008). Dietary Genistein Inhibits Metastasis of Human Prostate Cancer in Mice Cancer Research, 68 (6), 2024-2032 DOI: 10.1158/0008-5472.CAN-07-1246

Vucenik I, Shamsuddin AM. Cancer inhibition by inositol hexaphosphate (IP6) and inositol: from laboratory to clinic. J Nutr. 2003 Nov;133(11 Suppl 1):3778S-3784S.

W.-F. Chen (2004). Genistein Enhances Insulin-Like Growth Factor Signaling Pathway in Human Breast Cancer (MCF-7) Cells Journal of Clinical Endocrinology & Metabolism, 89 (5), 2351-2359 DOI: 10.1210/jc.2003-032065

  • Dianne Gregg

    Thank you for this article. I’m glad to see that you agree with me.

    I developed a severe allergy to soy (anaphylactic shock type) that
    I discovered on my own after doctors tied my 8 years of nausea,
    bloating and unusual weight gain to menopause.

    After spending 4 days in the ICU,after eating a soy-veggie burger, doctors said it was food
    poisoning – but I didn’t agree.

    When I started to research soy, I learned it’s not the health food it’s cracked up to be.

    That’s when I decided to write “The Hidden Dangers of Soy” to get the word out that if
    people are not feeling like themselves, try eliminating soy products and derivatives.

    Once I removed all soy from my diet I lost 35 pounds, and never gained it back!
    I have never felt better!

    Dianne Gregg
    http://hiddensoy.com/

  • http://summertomato.blogspot.com darya

    Excellent points. However I think it is also important to realize that in Western cultures, red meat is doing far more damage to our health than soy ever could. Also, though there are reasons to suspect soy might be involved in causing breast cancer, most of the data supports soy consumption in the prevention of breast cancer.

    This is a very complicated topic and I think the verdict on soy is still out. At this point, moderation is probably the best recommendation. However, the verdict is definitely in on red meat, and it’s not good.

    (No, I’m not a vegetarian and yes, I sometimes eat red meat).

  • Anonymous

    Soy is a healthy food, there’s no doubt about it – but don’t overdo it. People like Weston Price are paid heavy amounts of money to push the the negative garbage about soy. Make your own decisions and consume an amount you feel is safe.
    (I’m sure cow’s milk is way worse)

  • elma krom

    thanks

  • http://hiddensoy.com/ Dianne

    I don’t have a problem with fermented soy. I’m referring to all the processed foods we eat with unhealthy ingredients. The FDA says 25 grams of protein a day is safe – with all the processed foods out there, you are getting much more than that.

    You are correct—everything in moderatin (except for soy for me).

  • http://www.molivasac.com moliva

    i agree you dianne regards

  • http://www.biberhapibh.com biber hapi

    Excellent points. However I think it is also important to realize that in Western cultures, red meat is doing far more damage to our health than soy ever could. Also, though there are reasons to suspect soy might be involved in causing breast cancer, most of the data supports soy consumption in the prevention of breast cancer.

    i agree you …

  • http://hiddensoy.com/ Dianne

    I agree with your view on red meat – unless it’s grass-fed. I saw the movie Food, Inc. and it blew me away. I can’t buy meat in the grocery store (lucky for me… these days with all the recalls), because they are treated with antibiotics, hormones, and are fed soybeans.

    However, my research through the Gerson Institute forbids soy diets for cancer survivors because that can enhance the growth of tumors.

    Have a wonderful holiday!

  • capsiplex

    i agree you dianne

  • termal jel

    Excellent points. However I think it is also important to realize that in Western cultures, red meat is doing far more damage to our health than soy ever could. Also, though there are reasons to suspect soy might be involved in causing breast cancer, most of the data supports soy consumption in the prevention of breast cancer.

    This is a very complicated topic and I think the verdict on soy is still out. At this point, moderation is probably the best recommendation. However, the verdict is definitely in on red meat, and it’s not good.

    (No, I’m not a vegetarian)

  • altin çilek

    Excellent points. However I think it is also important to realize that in Western cultures, red meat is doing far more damage to our health than soy ever could. Also, though there are reasons to suspect soy might be involved in causing breast cancer, most of the data supports soy consumption in the prevention of breast cancer.

    i agree you …

    regards
    altin çilek

  • http://hiddensoy.com/ Dianne

    I have spoken to several cancer survivors and their doctors have put soy on the forbidden list. They know it’s difficult to do these days, but say try to stay away from soy as much as possible.

    • ozoderm

      I have spoken to several cancer survivors and their doctors have put soy on the forbidden list. They know it’s difficult to do these days, but say try to stay away from soy as much as possible.

      i agree you

      • Dianne

        Food has changed in so many ways these days. It is hard to avoid if you eat a lot of processed foods. I make my own bread because soybean oil is in all the breads on the shelf, or they were processed on equipment that used soy.

        And now with GMO to be concerend about – it makes it even harder – so, I just avoid products that I am not sure of.

  • Adrien

    Um, did you mean phytates? I’ve never heard of phylates with an “L.”

    This repeated spelling error is prompting me to lose faith in the validity of this article. This is REALLY bad.

Sajid Surve, DO

Sajid Surve, DO, is a physiatrist, acupuncturist, and osteopath who specializes in musculoskeletal medicine and integrative medicine.
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