Is Soy Really Bad for Us?

Monday Mar 6 | BY |
| Comments (45)

fresh tofu on table

Let’s have a debate about soy!


“You mean, you’re doubting the fact that soy is a horrible so-called “health” food that causes vegetarians to get sick and men to become effeminate from all the hormones it contains?” I already hear some of you say.

I don’t think there’s as much debate about any natural food as there is about soy.

Maybe it’s because tofu is associated with vegetarian diets and hippies; anyone wanting to criticize those diets chooses soy as their main enemy. Maybe it’s because some soy products have flooded the natural food market in such quantities that they’ve snuck into too many food products.

The real question is: is soy good for us or bad for us?

If you read any Paleo blog, soy is definitely one of the enemies. It gall goes back to an article that was published in Mother Jones that blamed soy for causing a number of health problems.

Soybeans are very particular compared to other beans because they contain phytoestrogens, which is a plant clone, so to speak, of our body’s natural estrogen hormones. These so-called phytoestrogen had been linked to some health problems such as low testosterone in men, low sperm count, increased risks of cancer, and infertility. These phytoestrogens are often classified as endocrine destructors. These are chemicals that interfere with the normal function of the hormones in the body.

In an article by Wellness Mama, “These phytoestrogens are so strong that a baby consuming only soy formula is consuming the equivalent hormones of four birth control pills a day.” Of course, there is no reference for that quote, but we’ll see some scientific evidence to show what these phytoestrogens can do.

One common attack on soy and beans in general, is the phytic acid that it contains. Another common complaint is thyroid health. Soy contains goitrogens, which are classified as antithyroid compounds, which can lead to thyroid problems.

When you look at the literature about soy, it’s very confusing because we have many contradicting studies:

  • In 1986, a two-year diet of soy for rats caused enlarged pancreas.
  • A 1989 study showed that soy products have no adverse effects on the human pancreas.
  • In 1991, a study was published showing that soy foods have a potential role in cancer prevention.
  • In 1994, another study was published dictating that soy diets may offer protection against breast, colon and prostate cancer. Also in 1994, Japanese and Chinese women were found to have low incidence of breast cancer because of high consumption of soy.
  • In 1995, another study showed that soy cannot be considered a factor in the low incidence of breast cancer among Japanese and Chinese women. A 1995 study also showed that soy inhibits growth of various tumors in rats.
  • A 1996 study showed that soy-based diets do, indeed, offer protection against breast cancer among Asians.
  • In 1997, a study showed that soy foods might reduce the risk of premenopausal breast cancer. That same year, the consumption of soy food was found to possibly decreased risk of prostate cancer.
  • In 2000, a study showed that soybean foods may prevent urinary track cancer.
  • In 2003, the consumption of soy foods was found to reduce the risk of prostate cancer. The same year, soy supplements were found to have minimal effect on prostate-specific antigen levels of prostate patients.
  • In 2004, consuming soy in green tea was thought to limit the progression of breast cancer.
  • In 2005, soy protein was thought to protect against cancer. That same year, soybean paste and kimchi were considered risk factors for gastric cancer.

As we can see, in terms of cancer, while the vast majority of studies show positive affects, we do not come across any studies that conclusively show that soy foods contribute to cancer. In fact, most studies done after 2005 show that soy foods are associated with lower cancer risk.

In 2009, a study showed that among women with breast cancer, soy food consumption was significantly associated with a reduced risk of death and recurrence. Another study showed that early soy food intake, for example, reduced breast cancer risk. In 2010, a study showed that the consumption of soy may reduce risk of colon cancer in women, but not in men. In 2012, a study showed that soy foods may reduce the risk of lung cancers in non-smoking women.

Now, when it comes to cholesterol, all the studies show that soy food consumption lowers bad cholesterol and increases good cholesterol, and reduces the risk of heart disease.

When it comes to these phytoestrogens and their affects, in 1995 a study showed that soy has no estrogenic affects on postmenopausal women. However, in 1998, a study showed that soy protein supplements substantially reduced the frequency of hot flashes in postmenopausal women. This was contradicted by a study in 2001 that showed soy protein does not reduce menopausal symptoms. In the same year, another study showed that soy products do have a protective effect against hot flashes.

When it comes to men, there is a meta-analysis published in fertility and sterility, based on fifty treatment groups that showed that neither soy products nor isoflavones supplements from soy affect testosterone levels in men. Some studies show that soy products reduce prostate cancer risk in men.

As for genetically modified soy, some studies show that there is reason to be concerned, and most studies show that there is no problem with the genetic modification of soy.

In terms of health and longevity in general, a 1988 study showed that a soy diet increases longevity. However, in 2005, a study showed that soy products should be limited in young children and consumption can lead to higher risk of cancer, male infertility, and may affect human hormones; this was published in the British Medical Journal.

This is just to show you how confusing the data is!

The Bottom Line & Arguments Against Soy

I would say that from reviewing those studies, soy shows promise and the vast majority of research shows positive affects.

We hear that soy contains anti-nutrients that interfere with the digestion of protein and the absorption of minerals, but this would be a problem if soy products were consumed raw, which is never the case.

For cancer, the vast majority of studies show positive affects on cancer; breast and prostate cancer rates are four to six times lower in Japan and China than in Western countries where little soy is consumed.

When it comes to sex hormones, some studies show problems. However, if we look again at soy-consuming countries, they not only have no problems making babies, but also have fewer hip problems, hot flashes and postmenopausal symptoms in women. In terms of thyroid issues, the problem may actually come more from iodine deficiency than soy consumption. Some studies show that soy isoflavones and soy isolates may suppress the immune system and reduce the size of the thymus gland. Overall, there are also other studies showing that soy actually improves the immune response.

After spending a few days reviewing the medical literature, I came to a pretty simple conclusion.

In reasonable quantities, traditional soy products are healthy. Refined soy products, while often being better than the meat products they replace, are best avoided. 

The way soy is consumed in the West is usually in the form of tofu, soy milk but more importantly soy isolates (textured soy protein that is used in protein bars, fake meats); they’re used by the food industry to replace other types of protein.

In Asian countries, people consume fermented soy products (such as tempeh and miso), as well as whole soy beans, also called edamame. They also consume tofu (which is made from soy milk). What’s important to understand is that soy foods are a part of the Asian diet, but they’re used more as a condiment. Roughly 5% of daily calories in a typical Japanese or Chinese diet may come from soybeans; that’s about 2 ounces of soy food or about 60g a day, which is not a huge amount. Here’s two ounces of tofu:


So, could it be that the vegetarians eating soy in America are a little over-doing it?

The Paleo blogging community has decided to attack soy viciously, and they have some reasons to do so. However, if we look at the evidence, if we look at the health of Asian nations compared to Western nations, and if we look at soy consumption in Asian countries, we can come to our own conclusions.

Personally, I do enjoy some soy products. I don’t consume huge amounts of it, but I do like to put little cubes of tofu in my salad, and consume other soy products, such as tempeh. I’ve never experienced any problems with this type of soy consumption — only benefits.

Please leave your thoughts below.

Frederic Patenaude

Frederic Patenaude has been an important influence in the raw food and natural health movement since he started writing and publishing in 1998, first by being the editor of Just Eat an Apple magazine. He is the author of over 20 books, including The Raw Secrets, the Sunfood Cuisine and Raw Food Controversies. Since 2013 he’s been the Editor-in-Chief of Renegade Health.

Frederic loves to relentlessly debunk nutritional myths. He advocates a low-fat, plant-based diet and has had over 10 years of experience with raw vegan diets. He lives in Montreal, Canada.


Comments are closed for this post.

  1. Amy says:

    I agree with Frederick.

    The fermented whole soy products are the better choice.

    Eating some miso soup or tofu, edamame, tempeh- and in sm quantities- such as a condiment

    seems like the way to go.

    I would not want to over do soy or eat processed soy and I would always make sure to avoid GMOs by getting organic!

  2. I quite agree with your study. I have lived over 50 years in Asia and enjoyed eating soy products. Of course we consume a quantity similar to the picture you publish. We also enjoy eating tempeh ( fermented soy cakes) which I love, and also miso. But we do not eat enormous quantities of fake soya meat, in fact we do not eat any.

  3. Evan says:

    Last time I looked … 1-2 ounces equates to 28 -56 grams … Your 10 g sounds a better suggestion …

  4. Marian J. says:

    What about soy formula? My daughter-in-law and son, who are eating more raw foods these days, have a 9 month old baby girl who is still nursing. On rare occasion she is given a bottle of formula purchased at Whole Foods. My daughter-in-law just learned she is pregnant with #2…a real surprise! Since she is still nursing #1, what should she now do? Continue nursing #1 at this time, and if not, what should be the substitute? Cow’s milk? Soy milk? No milk? Formula? So much conflicting advise out there today! Thanks.

    • Tanya says:

      I would NEVER feed any child of mine soy formula. Apart from all the debate over whether or not soy is good for you, virtually all soy now is GMO unless it is organic. You simply do NOT want to be feeding this to your precious babies. As for breastfeeding, I breastfed throughout 2 pregnancies, and breastfed my 2nd child at the same time as my 3rd. I didn’t have children thinking that I would do that, but it just evolved that way and I have no regrets whatsoever. My children were very happy and healthy throughout their childhoods only getting the occasional colds. Tell your daughter to get in touch with La Leche League, or other breastfeeding support places can give her support and facts rather than the negativity that many in our society have about breastfeeding. There is nothing better we can do for our children. 🙂 If she does wish to use formula then please get her to research the ingredients that are in them. Many really are not good.

  5. kitty says:

    Great article, thanks! I personally consume soy mostly in the form of fermented soy such as tempeh, tamari, and natto. When cooking with unfermented soy like tofu, I usually cook it with sea vegetables such as wakame (miso soup), arame, kombu, and hiziki. I believe that any beans including soy if cooked with kombu (high in glutamic acid) makes it more digestible. With regards to soy protein, I don’t eat it at all.

  6. john vanna says:

    As you know soy a processed food,It is also one of the most genetically modified.Many health writers have shown
    it is a by product of soy oil production.There is no “life force” in tofu.Can you eat it raw? When it comes to studies,one should always find out who funded the study,and that will tell you how the study will come out…

  7. Ron Grantz says:

    I’ve been eating tofu and eating/drinking other soy products for the last 11 years. I’ve never had any health problems related to eating they food items.

  8. Glenn says:

    You bring up a very hot topic. The trouble is that there is so much information and dis-information on this topic. And while you have correctly quoted many studies, there is no indication of the author and source of those studies, without which there is no clear indication of independence. In addition, for any study to be relevant the process they used needs to be examined, well documented, AND “independently” peer reviewed.

    The best book I read on this subject is called “The Whole Soy Story” by Dr Kaayla Daniel. In brief summary that does not do the book justice due to the detailed chemical and scientific analysis – not all soy is good for you, fermented forms are better, and it depends on the source of soy. A larger percentage of soy is genetically modified, which is another whole story on its own. In addition most soy products off the shelf have been highly processed. How does that fit into the whole food idea either raw or cooked?

    Because everyone has a story to share and something to sell, the bottom line is each of us need to make our own choices and decision based on works for ourselves. No two people are the same and many factors come into play where diet, food, mind, emotional are concerned.

  9. What jumps out at me when I think of soy is that I have read that it is one of Monsanto’s GMO products, and I try
    my best to avoid anything I know has been genetically modified. So it is not even on my radar.

    Thanks for the good work you do, though.


  10. Tracey says:

    I love this article … thank you! I drink organic soy milk and eat tofu occasionally … also, eat frozen soy desert. I feel healthy from it and most of my diet is vegetarian. I’m 60 and I’ve never had any cancer. I think it is good for menopause. The tempeh is good too and I have had edamame.

  11. ric says:

    its absolutely astonishing that he never mentioned that whole GMO Debacle. Any health
    professional who omits discussing GMO technology when arguing the pro’s and cons of soy
    has either been living under a rock for the past 20 years of just delusional. The GMO
    debate is essential when discussing soy, and yet it was completely omitted…makes you
    wonder if this so called health professional is in need of some $$ funds to continue
    traveling the world, since they don’t have a “real job” and just accepted some
    cash from Monsanto to write an article about soy without any Mention of GMO

  12. Neil says:

    perfectly said and well written. Fermented soy, yes appears the clear difference. There is soy and there is soy, there is exercise and there is exercise…………….

  13. Since my mind recollects I have been eating tofu and soy products that probably at my age of eight months to octogenarian my bones withstand many falls. Articles about soy depend upon the whims of a writer who wants something different from the views of others. For me, this is the truth about soy giving me good health, in spite of years and several falls of my body to the ground.

  14. Gavin says:

    The only soy that is good is fermented soy . As you say a very small amount of tofu e.t.c. may be o.k. but for sure consuming in large amounts is a health problem . Soy baby formulas should be banned as they have destroyed many lives of children ,especially males who`s penises did not develop .All parents all over the world should be made aware of this as they unknowingly give this to their children without having known the consequences , it is criminal to allow this to happen .On top of that Monsato have genetically modified soy ,and they are the biggest supplier , but profits mean more to them than the health of citizens . I know one body builder who was having soy proteins and shakes on a daily basis and grew breasts before he woke up where the problems were , obviously soy is no longer on the menu .Also as you say Asians only eat limited soy and almost always fermented ,most Europeans think they are healthy because of soy but are misguided on the type and amounts .we need to be educated of the dangers ,i can assure you many lives are being destroyed..Gavin……………

  15. Also Natto which is fermented Soy Beans is one of the Best sources of Probiotics on the Planet In my Opinion. But Always use Organic and Raw Natto.

  16. Nina says:

    The TOFU and other soy products are fermented in Asian countries much longer and in wooden boxes … in the West the fermentation process is much shorter and it is done in plastic containers. This makes soya not very good digestible. And the other important reason to avoid soya … because lots of soya beans are genetic engineered and there is little security that it is not mixed with not genetic engineered soya.

  17. Shan says:

    Great article on soy, which has become so controversial.Do you have any data on Soy Lecithin? I use Soy Lecithin in powder form with my protein shake daily morning. I appreciate your feedback as I always cherish your research/data backed articles and facts.

  18. Ema Lu says:

    There are two important variables about soy studies:

    1) in many country in the world the soy is GMO; what kind of soy is used for the tests?
    2) sometime (in Italy for example) it refers to soy beans products or green soy beans but it is mung beans, and they aren’t same kind of beans. What beans is used for the tests?

    Anyway, good article Frederic!
    Ema Lu

  19. Zilda Mattos says:

    Dear Mr. Patenaude

    I think one very important element that is missing in your discussion is WHO financed each research. If was the industry of the soy complex, starting from big corporations which produce the seeds, there is clearly a conflict of interest. Therefore, I would not take into consideration those studies. In fact, I would only be interested on independent research which are very scarce nowadays, unfortunately.

    Do you remember what happened to tobacco? For about forty years, half of the studies concluded that tobacco did not cause lung cancer (these were financed by the tobacco industry) and the other half concluded that tobacco caused cancer (these were independent studies). I would say that the same thing might happen to soybeans research.

    I do not want this “food” in my house, anyway.

    Zilda Mattos

  20. I am not a fan of anything GMO. Do we really know enough about the effects of GMO Soy? I am sure that even though the Japanese and Chinese consume Soy it is not GMO Soy. But I like the point that you made that they consume Fermented Soy like Tempeh and Miso and use it as a Condiment (or in small portions) not as a Main Course.

    Thank you for the information.

  21. Ruth says:

    I, for one, have found I am allergic to soy products. I have an immediate reaction, whether hidden or blatant. I have Hashimoto Hypothyroidism. I have tested a number of foods which have shown not to be good for me in a variety of ways. There is no doubt with soy. When I was on a Vegan Diet, eating a lot of wheat products and soy (tofu), my Hashimoto reading jumped up to 208. The range is 34 or below. I therefore disagree with your analysis.

  22. Neil says:

    Most of my life has been trying to sort out the reasons why we get sick, what causes it, how to avoid the causes, track down why symptoms persist when there is seemingly nothing wrong and so on.

    Some very positive findings have been:

    If something good for you is grown in artificial fertilizer and sprayed with chemicals it will have been rendered bad for you, even to producing allergic reaction.

    Glyphosate (Roundup and all the copies) is the leading cause of reactions in our bodies. A lady told me she was allergic to soy. I told her was not . Some time later she got in touch to say that it had been discovered she was not allergic to soy but was allergic to the sprays used on the crop.

    My findings have shown that rarely is the food itself the problem but how the food has been grown in the first place.

    There is great emphasis placed on eating only organic foods as this avoids a host of problems. I agree absolutely.

    Growing your own food is best providing you and your neighbours do not use artificial manures and chemical sprays. All must be done naturally. (The bees will be thankful too)

    Here in Australia we need to have a stronger and much larger Organic movement. At the same time we need to eliminate the wholesale poisoning of the environment.

    When in Miami and Los Angeles last year I was pleased to find that all the organic foods were indeed truly organic and properly labelled so. However I was equally disgusted to see the proliferation of damaging HF corn sugar.

  23. Jason says:

    how is 2 oz = 10 g??
    I like edamame, but from that natural state to tofu or soy milk makes them essentially proceeded foods and is where the problems comes up. As you said when consumed in such large quantities it can’t be good for you…

  24. Lynne says:

    Thanks for this article. I still have a lot of confusion about soy products. Could you please comment and provide more details about which products fall into the category of traditional soy products that you say are ok in reasonable and moderate quantities, and how to discern the refined soy products that ought to be avoided?
    I am also interested in hearing your thoughts about sprouted tofu, a product I purchase from Trader Joes in the U.S. Thanking you in advance. L

    • My thoughts on this are that “traditional” soy products are okay to eat as a regular part of your diet (even daily): no-sugar added soy-milk, edamame, tofu, tempeh, miso. Products made with refined soy protein are, in my opinion, are best included occasionally only. These would be all the “fake meats.” The ingredient list will usually include terms such as “soy protein” or “texturized soy protein.”

  25. Ellen says:

    Just noticed all the comments so far are dated from 2015, so obviously you have not revised it before re-printing it now. (You wrote “2 ounces of soy food or 7g-8g a day”. As used in the US, 1 oz. is 28 grams. In the Netherlands, 1 oz is 100 grams. In any case, the math doesn’t check out. Which is the amount you really mean: the 2 ounces or the 7-8 grams? This point was noted by other commenters in 2015.)

    I find it hard to reconcile the following two statements you made, when trying to determine how much soy I can tolerate, since my LDL is much too high, and I have low thyroid.

    — “all the studies show that soy food consumption lowers bad cholesterol and increases good cholesterol, and reduces the risk of heart disease”

    — “Another common complaint is thyroid health. Soy contains goitrogens, which are classified as antithyroid compounds, which can lead to thyroid problems.”

    Any further comments on how to balance those two? I used to eat only fermented soy such as tempeh and miso, but since Fukushima I don’t eat any products made in Japan, which greatly limits the source of miso. So I have been eating more tofu [organic, non-gmo], but with some concern.

    Thanks for your article!

  26. Michele Kaye says:

    Brilliant! This is a much needed review. Will use it in my nutrition talks and nutrition coaching.

  27. Nancy says:

    Thank you for another well written unbiased article presenting facts from different sources Well done ???

  28. Excellent commentary Frederic! I agree with your conclusion that small condiment like amounts of less processed soy like steamed edamame, and fermented products like miso, tempeh and tofu can be safely included in a healthy diet. I also think that people who are of the consciousness to eat meat alternatives such as soy may also practice many other healthy diet and lifestyle related habits, which could account for the positive outcomes in human studies. We, also in Western societies and especially in the US love to single out isolated foods like soy to be the culprit of our ill health issues and causes of our dis-ease; and fail to look deeply within ourselves where the real issues of our poor health often lie in waiting for our attention! We all know there is not one magic bullet of inclusion or deletion of foods in our diets that will cure the myriad of degenerative conditions related to inflammation and over acidity in the tissues that truly cause dis-ease in the mind and body. I applaud the information you shared in your well-rounded article! Because of it, I will be more mindful to use soy as a condiment (for flavor and in smaller amounts) just as I do with fresh meats and other concentrated foods. Kudos!

  29. Speckledy says:

    But isn’t most of the soy produced genetically modified and exposed to glyphosate!

  30. Joy says:

    Dear Frederic, Many years ago when I attended a “Way To Health” seminar at the Kushi Institute, one of the things they taught was that consumption of tofu should be no more that twice a week and in small quantity. Fermented soy, in the form of miso soup, was every day, but only one cup ( 1 tsp. miso per cup ) and the best miso to use for your daily soup was barley miso ( made with barley and soy beans ). I enjoyed reading your article on soy. It makes a balanced statement. By the way, is that a Russel Wright Spice tablecloth in the illustration? Thank you for your insightful and informative emails.

  31. Deb says:

    The part that upset me the most was–“most studies show there is no problem with the genetic modification of soy”—-are you kidding???!!! The genetic modification of ANYTHING is harmful!!! I see sentences like these from the idiots responsible for this crap all the time. They have put millions into our foods–that are now called GMO foods. The last thing they want are people proving how harmful it is. Nobody will buy it!! If it is so NON harmful–why would they not allow it to be labeled??? WHY?? Because the majority would not buy it!!!! All you have to do is note the UPC codes on the products: It starts with 9 and is 5 digits for ORGANIC///// It starts with 3 or 4 and has 4 digits for conventionally grown w/ pesticides/////// starts w/ 8 for genetically modified organisms
    Not much of a choice–but at least we have a choice.There is no reason not to buy ORGANIC all the time!!
    I want to live for a long time. Hopefully this will help!!!


  32. I totally agree with your conclusions about soy.

  33. Always follow the money when looking at things.

    Soy is a cheap developing world product commonly exported to the developed world for use in food especially ‘convenience’ food. Read cash crop not normally consumed locally and usually with big money involved.

    Soy flour has five properties that make it ideal for this role. Its relatively cheap, plentiful, multi-use, binds with fat and can absorb and hold up to five times it own weight in water. Exclude fermented soy products and then see how much soy is used in the food manufacturing industry.

    How much imagination do you need to see how this makes Soy an ideal product for the manufactured food industry??

    Then remember that we have a food industry in the developed world especially that does not care a bit about human health alongside a mainstream medical industry that knows little to nothing about nutrition.

    Follow the money because most Soy used is not there because humans need Soy nutritionally, its there for cost reasons, i.e. profit.

    • Sounds ominous said like that, but actually 85% of the soy grown worldwide is fed to animals. Soy to make tofu and vegetarian products is not a “huge industry” — at least not comparable in size to animal agriculture. Traditional soy products have been consumed by humans for thousands of years! They’re not a product of the food industry.

  34. Todd W says:

    Most of this article appears to show the benefits of soy consumption for women, which should not be surprising when considering the estrogen factor. Most of the “paleo” articles which I’ve read also mention that the Asians consume, for the large part, fermented soy products. The presented reasoning is that soy is problematic when it has not been fermented.
    No matter what, I would avoid GMO soy at all costs. I realize that that is almost impossible for most people today in the global food market.
    I drank organic soy milk for about 20 years. I had no loss of libido during that time. However, considering the time taken for many toxins to overcome our bodies’ natural immunity, that is also not surprising. (I’ve studied world-wide human medicine for over 30 years.)
    Today, I eliminate all non-fermented soy from my diet; and, as a male, have noticed an increase in libido in my 50’s.
    The old adage: Moderation in all things. Make of it what you will.

  35. Ivania says:

    Thank You so much for clarifying about the health benefits of Soya.

  36. nanci says:

    Hi Frederick,

    Thank you for your research.

    I understand that the majority of Soy Beans in the USA are GMO.

    This alone would cause hesitation in including Soy in the diet….yes?

  37. Jeronymo Sa says:

    I live in Brazil where most of the grains are GMO. Isn’t it a major concern when it comes to analize the pros and cons of consuming soy?

  38. Goranka says:

    Thank you for this overview Frederic. I find it very useful. I know that it took quite some time to collect and evaluate all the facts presented here. I appreciate very much the effort and your sharing the summary and conclusions.

  39. Anthea says:

    Nice article, Frederic – as always. I’m enjoying 3oz per day of tofu in my evening salad, so sounds like I’m pretty much in line with your recommendations.

  40. Thanks for all the research! I used to eat more soy products but then steered away from them for the past 5 years based on some of my in-the-know friends telling me that it is not good to consume. I can now embrace it again when I eat cooked foods.

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