Pin It

The Dangers of Soy

by Tiffany in Health & Healing

The Dangers of SoyEvery day there is more research being released about the dangers of soy in the diet, and if you aren’t already concerned about what has been discovered, the newest research will have you looking at soy in a whole new (and not necessarily good) way. I have long stayed away from soy but sadly in March 2011 I started eating some soy and did not even realize it… the results of this little oops have been a complete nightmare, but more on that later…

A Short History of Soy

Soy is a rather mundane plant that has recently seen an eye-popping increase in popularity. While soy farming originated in China back in 1100 BC, it was not grown for humans, but for animal feed and to help build up the fertility of the soil in between other harvests. In fact, soy beans were not considered fit to eat (for humans) until the Chinese discovered a way to ferment them; a process that made them digestible.

Today you’ll see that soy – fermented soy – is part of Asian diets in things like natto, miso, tamari and tempeh. Even so, Asians eat approximately 10-20 grams of soy on any given day. That is the equivalent of two+ teaspoons of soy (and fermented soy at that), and what they do consume is used mostly as a condiment to sprinkle on or add to other dishes, like soup. Interestingly enough, there is good reason to believe that the large amounts of soy recommended to Americans by soy manufactures (about ten times of the amount of soy found in the Japanese diet) can actually be harmful to your body.

Soy – Just What Your Body Doesn’t Need

So just what is the problem with soy? Well, for one thing soy is higher in phytoestrogens than most any other known food. A phytoestrogen is a plant-based estrogen that mimics the estrogen created by the human body (large amounts in women, smaller amounts in men). While there have been studies done to ‘prove’ that the phytoestrogens are good for you, the truth is that most of the studies conducted were financed and ordered by the soy manufactures, and independent researchers have shown that phytoestrogens consumed by humans who are already producing estrogen, can be dangerous to many of the body’s systems.

In fact, there is suspicion that the increasing numbers of breast cancer, endometriosis, uterine fibroids, infertility and low libido may be related to the increase in phytoestrogens. Interestingly enough each of these conditions is known to stem from unopposed estrogen (or estrogen dominance) in the body, and we’re starting our children off early by having them consume soy formula.

A frightening fact is that if a baby consumes the recommended amount of soy formula in a day, they are ingesting the equivalent of four birth control pills worth of estrogen every day. This fact alone may very well account for the increasing number of young girls entering puberty before the age of ten.

Soy is Goitrogenic

A not well-known danger of soy is that it is goitrogenic, or thyroid suppressing. A goitrogen works by preventing your thyroid from getting the amount of iodine it needs, eventually leading to thyroid failure. Once the thyroid starts to fail you gain weight, begin having mood swings, get cold and tired easily and start having problems remembering details. It can turn into a right nightmare, and is not something that you want to play around with.

Soy Contains Phytates

A Phytate is an enzyme inhibitor that blocks mineral absorption at the level of the digestive tract. Phytates can be found (naturally) in all grains, seeds, nuts and legumes, all of which either need to be processed, shelled, soaked or in some other way processed in order to make them digestible, but soy contains such a high amount of phytates that it is nearly impossible to get rid of them. In fact, the only way to make soy digestible for humans is to ferment it. Fermented soy products include miso, tempeh, natto or soy sauce (tamari).

Soy Contains Trypsin Inhibitors

As if the concerns listed above weren’t enough, soy is also high in trypsin inhibitors. Trypsin is a digestive enzyme that enables us to digest protein. Without it eating protein produces all sorts of side effects such as diarrhea, bleeding and stomach cramps.

So What is the Solution? It would be very easy to say that soy should be banned as a food product, but maybe we should take a leaf from the Asian’s book and treat soy not as a staple of our diets, but as a condiment that can be eaten in small amounts, but otherwise avoided so as not to open ourselves up to the multitude of problems that too much soy in a diet can cause.

So what has my experience been? Well I found out first hand about how soy is goitrogenic. In March I did two new things… I joined a gym and started eating eating a pre-workout protein bar. I picked some up initially just to try and loved the way they tasted. I wasn’t looking for performance enhancement just something that would be good fuel for morning workouts because I struggle to have an appetite for breakfast. Eating nothing until after 2:00 PM is not a good idea anyway but eating nothing and then working out for 2 hours seemed like a really bad idea. Since I don’t usually eat much processed food other than some Chobani pineapple yogurt it never even occurred to me to read the ingredients list. I eat whole, fresh foods so I never have to! Even so, it was a total bonehead thing for me to do.

I won’t name the bar specifically since it really doesn’t matter. I have since found out that 95% of those workout/health bars are loaded with soy, as was the one I was eating. I started out eating 1 bar 3 days a week and then I started eating them daily. By the end of month two I noticed my hair was falling out. Not little strands here and there but alarming chunks. I also noticed that I had 3 consecutive and supremely awful menstrual cycles. My periods are usually very uneventful. I don’t even get cramps so I had no idea what was going on but then toward the end of the third month was looking over my SparkPeople menus from previous months and found that my symptoms coincided with my joining the gym and eating those bars. It was a light bulb moment.. thank you SparkPeople! They deserve a separate post.

Anyway, I immediately went to the ingredients listing on the bars  and saw the soy. Case solved… I had been eating daily doses of unfermented soy and the plant estrogens were wreaking havoc on my body. But what exactly did they do? Well, I went to the doctor and had some blood drawn. The results were not good. I had become hypothyroid and they wanted me to take medication pronto. The goitrogenic soy combined with 3 weekly chlorine baths in the gym pool (chlorine blocks iodine receptors in the thyroid gland) had led my thyroid to malfunction.

Now I must disclose that hypothyroidism is rampant in my family… my father and older brother have it but I think a healthy diet kept it at bay for me until I royally screwed up. I have since read dozens and dozens of articles that link soy consumption to thyroid problems so I feel confident that is was the major culprit. Plus I felt great before the soy experience. Now I am kind of unsure of my next move. What I want to do is ride this out for awhile and see if a healthy diet can reverse the issue but frankly the thought of losing any more hair scares me. I tried the medication they gave me with much anxiety but stopped taking it after it made me all flushed and gave me a rash. And it made me tired which I never felt beforehand and that is what supposed to be what hypothyroidism does. Confusing much? Pharma meds and I don’t get along well and never have.

Read my follow-up to this post here with Natural Ways to Improve Thyroid Function. I also tell you about another soy caused health problem.

Recommended Reading:

The Whole Soy Story: The Dark Side of America’s Favorite Health Food

Tuesday, June 14th, 2011

53 Comments on The Dangers of Soy

  • Ashlee

    I find it hard to believe a few weeks of a bar including soy caused you hypothyroidism. To me it sounds pretty severe to have your hair falling out and far more likely you had undiagnosed hypothyroidism that was aggravated by the use of soy. I’ve seen lots of cases where soy aggregates hypothyroidism but none in which it causes it. I personally am a vegetarian with a family history of hypothyroidism. I drink the occasional soy milk, with a bowl of cereal a week ands be another glass a week. I have the occasional soy burger or tofu. And I get checked for hypothyroidism every 6 months. My thyroid levels are always awesome and experience no change with or without soy.

    I’m sorry for your hypothyroidism Dx but I’m not going to start avoiding it completely or eating animals because of it.

    My mom, who has a bad case of hypothyroidism, ran a test on eliminating soy completely and felt no better and her numbers did not improve at all. She did this test for two years. Hope you have better results but I can’t imagine they would be.

    • 8-12 weeks Ashlee. That is more than a few and I was not hypothyroid before the soy, sorry to burst your bubble. I am not sure where you saw that I or anyone is going to start eating animals now.. that is really a stretch. It is totally possible to be veg and not eat soy.

      • Ashlee

        So you were tested fr hypothyroidism immediately before starting your soy bar routine of 8-12 weeks? Undiagnosed hypothyroidism and not having hypothyroidism are different. I’m not sure what bubble you think your bursting I’ll take my medical knowledge over your propaganda.

        • Propaganda is communication aimed at influencing the attitude of a community toward some cause or position so as to benefit oneself. How do I benefit from sharing my personal experience? Or from anyone avoiding soy? I don’t.

          And for the record… I was not hypothyroid beforehand.. even if it makes you feel warm and fuzzy in your “medical knowledge” to pretend I was…

          • KWOrdonez

            No need to be mean in such a nice ways;) lol! I have to eat soy (I love it too much), but we need information that is counter to the corporations. Everyone knows what is best for their body, how their body responds to food. Everyone is different. Moderation is the best to go, and information is good for everyone! Thank you for the post, we all need to be aware how one responds to certain foods, and it might help other people or might not. Still a great post, we need more information like this for all foods! :)

          • I rarely eat soy and when I do I make sure it is fermented. I am vegan and do not feel the need to eat soy to get protein or any vitamins or minerals. If you knew Tiffany, Ashlee you would not be saying those things about her. This is her experience with soy, and you have no right to tell her how to feel and what conclusions she came to. Perhaps some people can eat soy in moderation and feel just fine, such as you. But that is your experience and I am not going to tell you, you are wrong for feeling or thinking that way, But that was not the case with Tiffany and all she is doing is sharing her experience. She is not spreading propaganda….seriously? That is silly to think this natural mama is. :)

  • Yikes. I’ve heard that the soy protein isolates (the kind in protein powders and bars) is the worst kind to eat, the body has no idea what to do with it. Sorry you are dealing with this, I’ve had thyroid issues in the past and it’s no fun. I would recommend coconut oil, lots of it (like 3-4 T a day, straight up) to help. :-)

  • Animatedstardust

    Powdered soy is bad for you, but edamame (soy beans & tofu are a fabulous food. Stay away from Weston Price info. – most of it’s horrible misinformation. Fermented soy products and tofu are VERY good for you. Asia knows this and has been consuming unprocessed soy in huge quantities for years with great benefits.

    • Sorry but this is simply wrong. Asians do not eat huge quantities of soy. This is a falsehood spread by soy companies.

      • Alicia Bayer

        I am reluctant to speak for what Asians eat since I’m not one, but I think it’s hard to generalize about what so many people in such a large area eat.  New Asian Cuisine has an interesting chart where they list the foods that are common in Asian cooking to correspond with our new food pyramid.  You can see that some Asian populations don’t eat a lot of soy (like Indian, Filipino and Burmese), while some typically only eat fermented soy (like the Chinese).  Others list soy traditionally eaten in many forms (like Korean, Japanese, Thai and Singaporean).

        I don’t eat a lot of soy and only buy organic (non-GMO) soy products.  Both dairy and soy milk are hard on my body, and I avoid both for my children.  I do think it’s important to follow the money with Weston Price though.  Their funders are mainly small scale beef and dairy farmers and related agribusinesses and while I know you don’t have an agenda in sharing this, they definitely do have a strong financial motive for promoting organic beef and dairy products and denouncing soy and vegetarianism.  Price himself actually never spoke out against soy and spoke highly of many vegetarian diets.

        I’m glad you’re feeling better and that you found what works for your body.  :)

        • Good points, Alicia re Weston Price. I know I base a lot of my opinion on Asian eating /cooking on my relatives. Yeah, I am a white gal but I have eight Japanese aunts and uncles, one aunt from Singapore, 1 Chinese nephew, and 4 family members that live in Indonesia. They don’t eat soy very much and especially not like Americans do.. drinking it and eating it in protein bars. And Americans never ate soy until these modern times. Weston Price is in my mind mostly about getting back to our roots and eating what our grandparents did. Old fashioned wisdom seems to be the most logical side to take in this.. at least for me.

          I actually didn’t even mention one of the most alarming soy side effects. For the 3 months I was consuming it I also got a painful lump under my breast.. so far this month.. nothing and I have been off the soy for about 40 days now. It just can’t be coincidence or related to anything but the soy.

          • Lady

            Well, yes, actually, it *could* be a coincidence. That’s the funny thing about coincidences…

  • Rosanna Stephens

    I agree with you here.  I became a vegetarian for a while and was regularly eating tofu, drinking soy milk, and eating other “meat” products based on soy.   I started experiencing major digestive issues and couldn’t figure out what it was until we ran out of soy milk one day.  Suddenly, my symptoms lessened.  I wonder if it was the trypsin inhibitor aspect of the soy because my symptoms involved EXTREME stomach cramps, diarrhea, etc.  I haven’t been able to eat soy in very large quantities since then, except for occasional soy sauce and miso.

    • Soy sauce and miso are fermented and the optimal way to consume it. ;) I use both in soups.

  • Harriet

    If you’ve read so many articles on it, would you mind seeing if you could dig out a few of them? Preferably information where i don’t have to pay for it like that book, if possible. In my personal statement for my nutritional biochemistry application, I mentioned about the possible problems with phytoestrogens from soy in the diet, but have since read this article and  decided I should probably find proper evidence than just people reporting on it. I hope you feel better and your hair grows back soon!

    • I like this article on The Billion Dollar Myth… it shows us quite clearly that we have to follow the money!

      The article you cited above bashes the Weston A. Price Foundation but they are just about the only ones seeking the information from independent researchers NOT bought and paid for by soy.. which is a billion dollar industry. So of course they are going to be the ones targeted by the soy proponents. And they have done tons of research:

  • Vera Falcão

    Hi, Tiffany, I wrote a post yesterday in my blog, like this one:

    I don’t like to eat soy, only shoyu and missô, sometimes tofu.


    Vera Falcão

    • Awesome Vera, great suggestions!

  • Deb

    Thanks so much for this excellent rundown on soy!  Since January, I have been replacing meat with nuts and legumes, and I am having digestive problems.  Your tip about the phytates in nuts may help me…thank you!

    • You are most welcome. Make sure to soak nuts before you eat them and if you want them dry and crispy you can dehydrate at low temps after soaking.

  • Artrun53

    I agree the only ways soy should really be consumed are if they are fermented. For a couple weeks in the beginning of the year a nutritionist had me do an elimination diet  to see if it would help with some issues (constant bloating,terrible gas/ect.); I also did blood work which actually came back all normal. I am vegan, and the elimination was very difficult. It excluded all gluten, soy products, all caffeine and added sugar. Honestly, the bloating went away as did the gas (sorry if TMI) . I could eat tons of beans and would still not have gas. I was supposed to do this with easing back into everything but I didn’t. I know soymilk is terrible for you, and my son drink’s almond milk. I am a heavy coffee/tea drinker and I have used soy for so long. I am back to where I started and have been for a while. I am thinking the main thing affecting me is the soy, since my coffee/tea is caffeine free now so the caffeine is minimal…but I put usual 1 cup soy milk with 1 cup of the coffee/tea 2-3 times a day. I have tried rice,coconut,almond milk and cannot find a substitute. Any suggestions or should I just have to deal with learning to like something new. I already had about 2-3 cups soymilk and it is only around 2pm. I probably would have another 2 cups by the end of the day….perhaps I should stop. I’m sorry this was so long… Any suggestions would be welcomed :)

    • Amanda

      You may just need to try a different type of “milk”. My husband and I drink Pacific foods organic Unsweetened Almond milk, which is becoming increasingly popular, probably because it doesnt contain soy lethicin, unlike Almond breeze until recently I noticed…it has virtually no taste so it should be easier to transition to. Good luck and good health to you.

  • Michelle

    98% of Soy in the U.S., unless organic, is also genetically modified.  I wish I had known about the GMO’s and the list you provided above when I was feeding soy to my daughter :(  Thanks for your post!  Lots of good info there that I had no idea about.  I had trouble with my thyroid while pregnant and was drinking soy the entire time.  I had no clue.

  • Melodieaubinelliott

    Everybody has a body and all bodies are different, i feel some have reactions to certain things and some dont its the way of the world.. i remeber reading similar info in the skinny bitch books… everything in moderation…. sorry for your bad experience, hope you are feeling better… ;)

  • Syndaly

    My son had a huge problem with soy based formula as an infant, so much so that we went to a homemade formula that helped soooo much.

    I thought he was meerly soy intolerant… but this is definately something to think about. 

    My dogs even react badly to soy, which is in a lot of dog foods. 

  • Gratefulmama4

    Last week, my daughter asked me what canola oil is, we googled it–yuck, and I thought it was the healthy one–and then we wondered what is in “vegetable oil,” and 95% is soy oil. GMO soy. We are down to coconut and olive. The things you never even think about–thank goodness I have a curiou child, and Google!

    Btw, cows milk based formula is also allergenic, and full of what we feed cows, and isn’t any better. Goxd gave us the perfect food for our babies, we need to educate ourselves and other moms to be–WE don’t live off canned dodos, why is that normal for a baby? But that is another topic…

    • Gratefulmama4

      Omg my spell corrector put in some weird words. Sorry!

  • Never knew that there were dangers associated with Soy. 

  • Shannon

    I suggest you find a doctor that will prescribe armour thyroid med.  It is a natural hormone supplement, not synthetic.  You may have to go to a holistic MD.  It doesn’t have any side effects and my doctor said that after a while we can try to take me off and see what happens. My thyroid have been normal after a short time being on it.  Wish you luck.

  • Great explanation of the dangers of soy, very well said!

  • Danniella

    I for one have been putting soy into my diet and have seen improvement, so the point is, is that i have been eating/drinking soy for three months and its had a positive effect. it’s also a great source of vitimen D, B2 and B12 not to mention iron and zinc.

    • karma

      Soy itself does not have Vitamin D3 or B12. It may be that the product you are eating has been fortified?

  • Rozzypozzy

    I have Hyperthyroidism, which was triggered by taking kelp tablets … perhaps you should try kelp?

  • momof2withbovineallergies

    I wonder if Honey made from bees who are only pollinating soybean crops would have the same negatives as just eating processed soy?

  • Angela

    Very well stated!  I knew about the phytoestrogens, but I was unaware of the other harmful effects of soy.  Do you know if the phytoestrogens in flax seeds are as harmful?  Does the body see them differently?  Just wondering why soy would get a bad rap and not flax.  Thanks for the info.

    • IMO flax should also be limited too.

  • Lisa

    I LOVE you for this Tiffany! I also avoid soy and feel it’s not worth the risks. 

  • Read my follow-up to this post here with Natural Ways to Improve Thyroid Function. I also tell you about another soy caused health problem.

  • Christine

    I have been in the know about the dangers of soy for a while now yet I’m still finding it so hard to believe. I have troubles with dairy so when I got pregnant, before I knew anything about soy, I started drinking a large amount of soy milk  to get an adequate amount of calcium and other vitamins. I had never been healthier, and I am now a proud mom of a extremely healthy little girl. When I learned about soy dangers I started cutting back on the consumption, yet even though I still eat a healthy diet, I never feel quite as healthy as I did when I was pregnant. I’m not sure why this is.

  • Atippey

    check out great info on natural thyroid supplementation.

  • Salmonslayer1991

    BAD SOY BAD BAD BAD thanks for the update!

  • Kimberly

    My 4- and 5-year old children have been taking swimming lessons for over a year now and we are all in the pool several times a week, year round.  Can the chlorine from pool exposure alone cause thyroid problems?  We filter chlorine from our drinking and tap water and have eliminated it completely from our life otherwise due to its detrimental affect on environmental and ecosystem factors.  However, where swimming is concerned, for the average family it is next-to-impossible to avoid chlorine.  Should we now also discourage recreation in the pool?  Or does chlorine merely contribute to further adverse effects in an already stressed, malfunctioning or malnurished thyroid? 

    • Kimberly,

      I don’t think the chlorine alone would have done it. I was eating soy bars 1-2 times per day and that alone would have/did cause problems but the chlorine helped advance an already emerging issue. I am still swimming 3 days a week, I am just making sure to rinse in the showers thoroughly afterwards and things are improving even though I haven’t given up my swims.

  • soyisbad

    I had a bad experience with soy too. For a year I was unable to conceive, and my cycles went all over the place. I had tests done and nothing came up. I stopped my soy intake—my cycles regulated straight away and I conceived.

  • Pingback: SparkPeople Love | Nature Moms Blog()

  • Pingback: Pumpkin Shake Recipe | Nature Moms Blog()

  • Pingback: The Conscious Box – Ethical Goodies Abound | Nature Moms Blog()

  • Pingback: A Diet for the New Year – Or Why I am Going Primal | Nature Moms Blog()

  • Smlynch79

    Wow, awesome post! I have hypothyroidism on both sides of my family and was wondering if my sudden weight gain (which seems weird, I honestly don’t eat that much!) and low mood might be to do with a thyroid issue (now I’m getting into my 30s). Then I made the connection between when this all started and switching from milk to soy milk… I guess I’ll have to wait and see what happens now, but many thanks for this post!

  • Pingback: School Snacks! Healthy, Chewy, Granola Bars. | My Healthy Green Family()

  • Karen Larson Kendall

    I have a question – I’ve been using about 1 cup of soy milk per day to regulate my menopause symptoms – after reading this – my usage scares me.   I know it is helping because I stopped drinking it for a while and boy did my hot flashes/emotions were impacted.  What else can I be using?

    • Karen it is possible that due to your menopause you are benefiting from the hormones in soy ala hormone replacement. I just know that for younger woman who do not need the hormones it can do very bad thing and mess up their homronal systems already in place, like it did mine. As long as you remain vigilant and you are actually seeing benefits (and none of the warning signs) I would not worry so much. If it does worry you though perhaps you can read up on bio identical hormone replacement and ask your doc. Also, fennel and alfalfa are other foods that have phytoestrogens in them you may want to try. Because they are not found in numerous other foods it would be much harder to overdo them.

      • Karen Larson Kendall

        Thank you for your input Tiffany!  I am being vigilant.