5 Reasons Soy is Not a Health Food

July 28th, 2014

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Soy milk, tofu, soy veggie burgers, and other soy products are touted as healthy alternatives to meat and dairy. Many vegetarians and vegans rely on soy as a main source of protein because of its proclaimed health attributes. However, even if you are a meat eater, you are likely eating a substantial amount of soy every day.

Much like corn and wheat/gluten, soy pervades the American diet and is in practically everything. You will find it in milk substitutes, dressings and sauces, chocolate, body products, cakes, crackers, and infant formula. Soy lecithin is an emulsifier that is added to many processed foods such as chocolate, baked goods, and bottled smoothies. Soybeans are also used as animal feed, therefore soy is present in your meat products if you aren’t buying grass-fed or pasture-raised.

I don’t consider soy a health food, and here are five reasons why:


1. Over 90% of soybeans in the United States are GMO.

“Genetically modified organisms,” or GMOs, are plants and animals that have been created by combining DNA of different species in a way that could not occur in nature or by traditional cross-breeding. Significant evidence is beginning to surface that GMO foods promote disease.

Due to cross-pollination by wind and insects the remaining 10% of non-GMO soy isn’t guaranteed to be non-GMO. Assume that all soy in the United States is GMO, and that buying only organic soy isn’t necessarily going to protect you.


2. Soy contains chemical compounds called “isoflavones” that mimic estrogen.

Estrogen occurs naturally in your body and remains in careful balance with your other hormones. Too much estrogen causes reproductive difficulty in both men and women, and has been implicated in cancer development.

The estrogen-like compounds in soy have been shown to increase tumor growth in animals, leading researchers to speculate that they may have a harmful effect on a developing human as well. Avoid giving an infant soy-based formula, as they are rapidly developing and are especially sensitive to hormones and hormone-like compounds.


3. Soy can cross-react with gluten.

Soy is one of the top allergenic foods in part because it resembles gluten on a molecular level. If you have a gluten sensitivity, your body can’t distinguish between gluten and soy. Your body could react to each food with the same immune response. If you’ve given up gluten but haven’t seen a decrease in inflammation, consider that soy in your diet could be producing your symptoms.


4. Soy is a legume.

Soybeans and other legumes are not easily digested. All the protein they contain is not available to be absorbed by your body.

A bean is a seed, and seeds are designed to withstand digestion in order to be “planted” by the animals who eat them. Soybeans are high in phytic acid, a digestion inhibitor that binds to certain vital minerals (specifically zinc, iron, and calcium) and prevents their absorption. Not only can this lead to mineral deficiencies, but undigested food particles sitting in your gut feed gut infections and irritate your gut lining. A compromised gut lining (or leaky gut) is a determining factor in the development of autoimmune disease.


5. Soy is goitrogenic.

Soybeans contain chemical compounds called “goitrogens” that suppress the thyroid gland by inhibiting the uptake of iodine. Iodine is necessary for the synthesis of thyroid hormone. If you have an underactive thyroid, make sure you’re getting enough iodine, and avoid soy. Too much iodine can be harmful, so it’s important to eat a diet rich in a variety of other thyroid balancing minerals, like selenium and zinc, and take a high quality multivitamin.

Other vegetables, especially cruciferous vegetables, are also goitrogenic. The benefits of eating antioxidant-rich vegetables like cabbage, broccoli, and kale far outweigh the risks posed by the goitrogens. Soy on the other hand isn’t worth it.


Just as people who are gluten-free sometimes rely too heavily on gluten-free products, many vegetarians depend upon soy products as meat alternatives. A soy-based vegetarian diet is likely not a healthy diet, so decrease your soy consumption as much as you can and replace it with nutritious alternatives like dark leafy greens, cruciferous vegetables, and protein-rich nuts and seeds.

Whether or not you are a vegetarian or vegan, avoid relying on soy as your main protein source. Most of us eat too much soy as it is. It’s best to limit your soy intake, but if you are going to eat it, it’s important that you:

  • Buy 100% organic soy.
  • Eat soy in its whole, unprocessed form (edamame).
  • Read package labels carefully.

To determine whether or not you have a sensitivity to soy, try completely removing it from your diet for at least two weeks and then adding it back in, tracking your symptoms along the way. I’ve created an eCourse to help you through this process if you need some extra guidance.


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  • Kate Lauren

    As a Celiac, I am with you about soy. Here’s my question: What about fermented soy products? Are they classified as the same in your book, and cause the same problems in the body? Thanks for your answer.

    • I’d still avoid them honestly, but it’s really about what your body can tolerate. There are other fermented foods, like sauerkraut and kimchi, that I would choose over fermented soy!

  • Antony Daamen

    It sounds pretty good, but where are your quotations to the scientific studies being done, or proof that this is right? (I dont use soy… love my milk!

    • There are several linked studies in this article.

  • deedlelee

    I wonder about the people who were fed a lot of soy infant formula because they were allergic to the regular infant milk formula. Have they grown up to have thyroid problems? I am an RN that used to work in a Newborn Nursery of a hospital. I fed soy formula to lots of newborns! If an infant was a spitter (spit up its formula), we would get the doctor to change the milk to soy instead. It usually helped. I wonder if they are still doing this. I haven’t worked in the newborn nursery in a while.

    • I’ve wondered that myself. It’s one thing I actually ask my patients, “were you breast fed, fed cows milk, soy formula” etc

      • mbrmlg

        I was an infant who probably was not breast fed, could not tolerate milk, could not tolerate soy, and was fed goat milk. I was still a colicky baby, apparently. As a toddler, child and adult, had milk all my life and did not realize that the abdominal pain that I lived with WASN’T normal. Negative for celiac and GI workups, the years of IBS eventually compounded to chest pain (microvascular dysfunction, diagnosed by challenge cath). Chest pain started in my late 30s to 40ish. Cath at age 52 after too many MDs thought it was psychosomatic. A few years after being nitro dependent and suffering MI like pain, all day, every day led me to a feeling like life wasn’t worth it. I was having some PT and the practitioner told me it wasn’t normal to have skin turn red from bodywork (inflammation), and referred me to a progressive nutritionist. Food sensitivity testing revealed low grade sensitivities to dairy, eggs, GOAT, black pepper, legumes and yeasts. I also had a friend who became a GAPS certified practitioner. At age 58, I started GAPS. My QOL was terrible and to do GAPS felt like more loss, but It was the first time I’d ever experienced a belly without pain. Suddenly, I could bend my chest to my knees in a sitting position and lie there flat. It didn’t bother me to wear a bra. My skin changed and people told me how good I looked. Most importantly, MY CHEST PAIN REGRESSED and over time, I dropped the 12 hour nitroglycerin. The PVCs stopped. The SOB stopped. Obviously, my micros in my heart were happier (and I have LP(a), a genetic glitch that can lead to higher rate of MI/stroke), now, I could see that my heart symptoms WERE NOT HEART, but gut that had gone systemic. The micros in my heart was signaling that they were under attack. I no longer felt like a walking and evolving MI, unable to tell the difference. Granted, I also did other modalities to help resolve how compromised my body had become. I did EMDR for early trauma and i had UPLEDGER/BARAL bodywork to do myofascial release from the years of rigidity and pain in my gut and in my chest cavity from the chronic ischemia (oh how that helped!) Now 60 and educated about this, I still struggle with the human desire to eat things I know are wrong for me. Regardless of this, I follow GAPS (without the legumes and dairy and eggs – I don’t like goat) but I do get occasional brushes with wrong ingredients. What a journey! Thank you for the information; every bit helps. To feel like you can regain health you never had at this age is amazing! I only wish we’d known all of this so many years ago.

    • Jade Ah Ho

      wow this is a concern for me. My grandson could only drink soy and now with all the gmo. my heart is hurt cause I don’t want anything happening to my grandson as a result of drinking soy milk

    • Jade Ah Ho

      maybe change to hemp milk?

    • Meagan

      Hello! I am an example of a baby who was unable to breastfeed, and was fed soy formula. I also grew up in a mostly vegetarian household so we ate a lot of processed soy ‘veggie meats’ when I was growing up. I am 36 and a year ago discovered I have Hashimotos. My cousin who is my age grew up eating a lot of processed soy ‘veggie meats’ as well, and had thyroid cancer a year ago. He had to have his entire thyroid removed. Only two examples, but I wonder how many more of us there are?

  • Sophia

    Dr. Myers, I’ve recently poured myself into doing so much research on food and holistic alternatives to treating MS. So I learned early on about eating non-GMO foods, etc. My question: If 94% of soy crops in the US are genetically modified, where can we actually find the other natural 6%? And be sure of it?

    • Sophia

      I ask this because a friend of mine recently gave me some vitamin packs from ‘USANA’ to try. She has a degree in biology and used to work in a lab, so she says she trusts this product since it treats cells on a molecular level. This product also sponsors a few Olympic athletes. The first thing I noticed (I immediately read the ingredients when about to eat something)- was that these vitamins contain soy lecithin. So all my excitement to try the product went away, since I am trying to follow your advice in avoiding soy.

      • You really cannot be 100% sure that soy is non-GMO. I say that because due to cross-pollination by wind, insects, etc, non-GMO soy can be crossed with GMO soy to create a hybrid without anyone even intending it. Now soy lecithin may or may not affect you. You can always try eliminating it for a few weeks, and then adding it back in for a few days to see how you feel.

  • Angeles Rios

    What are your thoughts on natto?

  • Thank you for writing this. Some of this I already knew, and some I did not. Up until a few years ago I thought soy was a health food and ate it regularly. I much regret doing so, even if in ignorance. More people need to realize this and talk to their doctors about it. Perhaps not everyone has the same hormonal sensitivity to soy, but this article gives a few more reasons to boot.

  • Laurie

    What about the soy derived phosphatidylcholine in phospholipid exchange therapy for detoxification ( ie. Lipostabil)? Does the soy make it a bad treatment?

    • Sometimes the benefits outweigh the risk. I wouldn’t recommend soy as a healthy food, but if the treatment is overall beneficial, I wouldn’t throw it out completely because of soy.