GAPS Diet & Nutrition

4 Reasons to Avoid Soy

Soy is touted as a health food, and yet it is found, unfermented and highly processed, in just about every junk food and processed item in the grocery store. And unfortunately, all commercial chickens, turkeys, ducks, dairy cows, pigs and beef cows (unless specified “grass fed”) are fed a soy-based diet, which impacts the health of the humans who eat them. All of them. You cannot find any meat product (besides grass-fed beef or lamb) in the grocery store that has not been contaminated with soy.

I personally avoid soy and will not even feed my animals soy. Here are some of the reasons I avoid soy:

1. Soy Consumption Can Cause Hypothyroidism

Consuming soy creates a three-fold increased risk of hypothyroidism. –The effect of soy phytoestrogen supplementation on thyroid status and cardiovascular risk markers in patients with subclinical hypothyroidism: a randomized, double-blind, crossover study and –Soy phytoestrogens increased risk for overt hypothyroidism

2. Soy Consumption Can Cause Thyroid Cancer

Thyroid cancer is an “estrogen-dependent disease” and soy has extremely high levels of phytoestrogens. A diet that is low in soy (which is impossible if you are eating packaged, processed foods and conventional meat from American grocery stores) is preventative against thyroid cancer. –Phytoestrogens and thyroid cancer risk: the San Francisco Bay Area thyroid cancer study

3. Soy Consumption Can Cause Endometrial Cancer

Long term treatment with soy supplements causes endometrial hyperplasia, which can lead to endometrial cancer. –Endometrial effects of long-term treatment with phytoestrogens: a randomized, double-blind, placebo-controlled study

4. The Relationship Between Phytoestrogens in Soy and Cancer is Confusing, to Say the Least

I am not going to volunteer to consume soy for this reason: it does something to cancer. There are several recent studies (many funded by soy product manufacturers) that say that the phytoestrogens in soy will prevent or diminish various types of cancer. This research is questionable (we should always question studies that were funded by the food manufacturers themselves), because there are also studies that prove that the exact opposite is true–that the phytoestrogens in soy may increase chances of cancer or cause cancer to grow. One study said that phytoestrogens from soy may be beneficial in protection against cancer if fed before puberty. –Phytoestrogens and breast cancer Another study says, basically, they really don’t know. We know that estrogen causes breast cancer, but we don’t really know if phytoestrogens (plant-based estrogens) in soy cause or prevent breast cancer. It says, “the relevant research is complicated, inconsistent, and inconclusive.” –Phytoestrogens and breast cancer And yet another study says that phytoestrogen from soy can “markedly enhance tumor cell proliferation,” thus causing the cancer to grow. –Phytoestrogen Interaction with Estrogen Receptors in Human Breast Cancer Cells 

I’m avoiding it, because the truth is, we really don’t know. It’s not a necessary part of the diet. Unfermented soy was not eaten by any traditional culture, and therefore, we do not even have anecdotal evidence of any health benefits of raw or processed soy.

Do you consume soy? Do you think that it is a healthy food?

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  • Erica

    One summer I switched to soy ice cream and my periods got completely whacked out. It took months after stopping for them to get regulated again. I avoid soy as much as possible because of that and because I had heard they were all GMO’d up. But, I had ZERO idea that all the animals are fed soy-based diets. I am slowly switching to grass fed animals. Am I reading correctly that there is no way to eat chicken or turkey without also eating the soy? I hope not. Thanks for the informative article.

    • TraeChicDesigns

      We raise our own poultry without corn or soy. It’s an easy adventure – even on the smallest of properties. If you have an apartment or condo, consider splitting costs and duties with someone that can house them on their property.

  • Dora Collier

    I ate soy once in a dish someone offered me and it immediately gave me cramps in my stomach and made me constipated. Soy is a GMO food.

  • Karen

    You really need to do your homework. I simply googled soy and cancer studies, and every study that I read about done by a medical establishment (NOT a food company) either said that moderate amounts of soy are fine in your diet, or that there is no evidence linking soy to increased cancer risk and that more studies would be needed to explore the matter further. I see that your quotes come from “a study” but what studies? Where’s your documentation here? I’d love to see what studies you’re looking at, because the American Institute for Cancer Research pretty much disagrees with everything you’ve said here.

  • Anonymous

    I have no protest against avoiding GMO foods, but I don’t think there is anything to fear in the soybean itself. The studies that did seem to prove something used supplementation with high levels of soy protein and phytoestrogen, which is not what you get when you eat a reasonable amount of foods made from a soybean. And even then the study on hypothyroidism began with patients who already had the early stage of the disease. That study only suggested that those who already have hypothyroidism may consider not consuming a high amount of soy products, and nowhere did the results indicate that soy causes it hypothyroidism. And the conclusion was that 10% of the patients on a high level of supplementation developed overt hypothyroidism, which was quite likely to happen anyway considering that they were already at the subclinical status. Yes soy contains “phytoestrogens.” They are not estrogen itself and most studies indicate that they are beneficial. Many studies are also inconclusive. My take? Don’t be afraid of a soybean! If you can find a non-GMO, organic soy product (or make it from your own soybeans if you just don’t trust the label!), I think it can be consumed safely in moderation. Too much of any food, including supplementation of vitamins and other things, can pose a risk. I think it’s most important to eat a diet that includes a variety of healthy, minimally processed foods. So much more could be said. The best thing to do is to look up all the credible studies (agreed, not from the makers of soy products OR from those opposed to soy) and read them critically and without bias. Notice what form was used, how many participants, what other factors could have been involved, and if the results are significantly conclusive or just a possibility, etc. Don’t just take someone else’s word for it, because the entirely wrong conclusion can be drawn from reading a study due to the readers bias!

  • Sandy

    So, let’s say your a woman and your periods are out of whack due to perimenopause and the decrease of estrogen causing insufficient build up of the lining of the uterus to the point of break thru bleeding every month, would eating soy help? I’ve tried the bc try as regulating this and the estrogen in those is still too low.

  • Kat

    but what about the Japanese culture and their relationship with soy? they are very healthy and live quite a long time

  • DeniseofPA

    Seriously, for every food that has health benefits they also find a disease it causes. My family raised its own soybeans and we ate them and none of us had any of those issues.

  • Joan Wyffels

    I feel safe with organic soy but most soy is GMO and I feel this is unsafe for human consumption and needs much more study.

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