Home cooking Soy: Scary or Not? 3 Fears Discussed

Soy: Scary or Not? 3 Fears Discussed

January 27, 2016

There was a time, many years ago, that I feared a bean.  A little ol’ soybean.

I turned up my nose when I walked by the tofu section of the market and scoffed at the notion of drinking it as soy milk. I  was convinced that it could cause, among other things, the likes of: hormonal problems, cancer, weight gain, and might give my then boyfriend (now husband)  moobs (man boobs for the uninitiated).

But, I’m not the only one who had soy-based fears.

Never has there ever been a food that has stirred up quite so much controversy. In fact, the benefits and harmful affects of soy have been so hotly debated that it has earned the distinction of being one of the most researched foods ever with over 10,000 peer-reviewed journals on soy published between 1990-2010 (Soy: What’s the Harm?, Vegan Health.Org). The results concluded in these studies vary widely and are often contradictory.

Unfortunately, so many published papers with incongruous results means that one could inevitably find data to support their particular stance or agenda. For example, feeling threatened by the growing soy industry, many believe the meat and dairy industries are behind perpetuating some of the misinformation about soy. I would check the sponsor  the next time you come across a “study” proving that soy is dangerous.

It’s also important to note that most of the concern surrounding soy is attributed to results gleaned in medical studies using rodents in which high doses of  isoflavone, a phytoestrogen, was shown to promote tumor growth. This would be concerning  if animal studies were reliable predictors of human experience ; however, we know that the biological processes of rodents and humans are wildly different, so how can one extrapolate that soy isoflavone could promote tumor growth in humans by that measure?

But,  by the same token, one should approach animal studies showing a correlation between soy and a decreased risk in diseases like cancer in the same way.

So what should we think?

As I’ll explain while I address 3 of the most prevalent fears of soy, mounting research (human and animal) has dispelled many widely circulating myths about soy and its popular fermented iteration, tofu. Furthermore,many of the  purported issues have less to do with the bean and more to do with how it’s grown or processed.

At the very least, learning about soy has really illustrated to me the disconnect that so many people have with what goes into their bodies and that many of the concerns they have about soy should actually be redirected to the animal based products they might be consuming.

Without further ado, here are three common fears about soy and why they’re mostly unfounded.

*Keep in mind that I’m talking about whole and fermented soy foods labeled organic or Non-GMO: whole soy beans (think : edamame) , tofu , miso, tempeh, soy milk, etc. I am not addressing soy foods, like soy isolate, found in myriad processed foods.*


 Fear #1 : Soy contains estrogen and can have dangerous effects on the body and reproductive health

Soy contains a number of phytochemicals, one of which is called isoflavone.

Isoflavone is commonly referred to as phytoestrogen because it is a compound in soy with a similar chemical structure to estrogen and is capable of exerting estrogen-like effects in the body.

Soy fear mongering focuses most heavily on the supposed havoc isoflavone can have on our bodies due to it’s potential to have estrogenic effects; the development of  hormone related cancers (uterine, prostate, and breast, for example) highest on the list of possible concerns.

While it’s true that isoflavones can mimic estrogen by binding to estrogen receptors, one should keep in mind that estrogen receptors are found throughout the body and research has shown isoflavones to actually block the effects of estrogen in certain tissues.

Scientists are interested in the tissue-selective activities of phytoestrogens because anti-estrogenic effects in reproductive tissue could help reduce the risk of hormone-associated cancers (breast, uterine, and prostate), while estrogenic effects in other tissues could help maintain bone density and improve blood lipid profiles (cholesterol levels). The extent to which soy isoflavones exert estrogenic and anti-estrogenic effects in humans is currently the focus of considerable scientific research. (Oregon State Micronutrient Information Center)

There’s plenty of evidence showing that soy isn’t the cancer causing monster it’s made out to be. This is what the American Institute of Cancer Research says about soy in their database of  foods that fight cancer.

“Because soy contains estrogen-like compounds, there was fear that soy may raise risk of hormone-related cancers. Evidence shows this is not true. Soy’s possible effects on health is an active area of research.”

And this is  what the Physicians Committee For Responsible Medicine has to say  :

Epidemiological studies have found that soy protein may reduce the risk for cancers including breast, colon, and prostate.1

To further consider the health effects of soy in humans, instead of animal based studies one might consult the various observational studies conducted, particularly those  in Asia, where soy is a dietary staple. Asians have been consuming soy since time immemorial and they are among the healthiest populations on the planet.

Population studies link soy consumption with lower breast cancer risk in Asia, where women consume moderate amounts of soy throughout their life. A moderate amount is approximately one to two servings a day. Research now suggests that hormone-related protective effect of soy against breast cancer relates to soy consumption in childhood, adolescence, and throughout puberty (The American Institute of Cancer Research)

Apart from isoflavone, other phytochemicals in soy have been shown to have health benefits, too.

Saponins: studies suggest these compounds may lower blood cholesterol, protect against cancer and affect blood glucose levels

Phenolic Acids: this group of phytochemicals is being studied for their potential to stop cancer cells from spreading

Phytic Acid: commonly found in cereals and legumes, it can act as an antioxidant

Enzyme-regulating proteins: these include protease inhibitors and protein kinase inhibitors

Sphingolipids: they seem to play a role in regulating cell growth, self-destruction of abnormal cells and progression of tumors (American Institute of Cancer Research says about soy in their database of  foods that fight cancer)


Legitimate hormonal concerns in your diet

I also want to state what you may not have considered, but becomes painfully obvious when it’s made clear: if you consume animal products you are ALREADY consuming hormones and growth factors that can interact and interfere with your own hormones.

While you may be careful to consume milk or meat labeled “hormone free”, please know that this is misleading because there are already naturally occurring hormones present – it came from a living being, after all.

One cannot be justified in fearing the supposed hormonal effects of a plant when one is consuming actual hormones from an animal. Julieanna Hever, also known as the Plant Based Dietitian, says:

IGF-1, found in animals, boosts our own body’s production of the hormone and adds to it by coming in exogenously. Excess IGF-1 promotes cancer growth.

Let’s further illustrate this fact by using  dairy as an example. The milk you drink and the cheese you eat came from the breast of a cow who has recently given birth to a baby cow.  The milk contains nutrients and hormones intended to nurture a cow – not a human.

In the following clip, from Cowspiracy, Dr. Michael Klaper, of True North Health Center, explains :



Also consider that milk from pregnant cows contains even higher levels of naturally occurring hormones. The milk our ancestors drank is much different from the milk humans drink today and this is due to how dairy cows are raised.  Due to demand and industrialized milk production, cows in the dairy industry are artificially inseminated and live out their lives in constant cycles of pregnancy, birth, and milking. An individual cow could spend 10 months of the year being milked and spends part of that time pregnant. Increased hormones in her body are in her milk and consumed by humans.


Fear #2: MOOBS (MAN BOOBS)or more technically, Gynecomastia

I suppose this would fall under fears of hormonal disruptions, but I felt it deserved it’s own stand alone category because it’s something that I hear often.

Just the other day I was chatting with a friend over lunch when I asked if he wanted to try my tofu burrito and, sure enough, he cited his concern of man boobs as a reason he doesn’t eat soy.

I will kindly direct him to this information, courtesy of the Physicians Committee for Responsible Medicine:

Soy products have no adverse effects on men and may help prevent cancer in men. A meta-analysis published in Fertility and Sterility, based on more than 50 treatment groups, showed that neither soy products nor isoflavone supplements from soy affect testosterone levels in men.13 An analysis of 14 studies published in the American Journal of Clinical Nutrition showed that increased intake of soy resulted in a 26 percent reduction in prostate cancer risk.14 Researchers found a 30 percent risk reduction with nonfermented soy products such as soymilk and tofu.

And if you skipped over the video I posted, please watch and note the point when Dr. Klaper says dairy milk is a cause of man boobs. So again, one can’t really be justified in their fear of soy if they’re consuming dairy products.

Fear #3: Soy is all GMO

Genetically Modified Organisms are organisms that have been genetically manipulated to exhibit a particular trait that would not otherwise occur in nature. Soybeans have been genetically modified to resist herbicides. The obvious benefit to farmers being the ability to kill weeds using herbicides without killing their crop.

There has been growing concern among consumers over genetically modified foods and the potential health effects, including allergies. While the GMO controversy is on my radar, I’m honestly not terribly educated about it, so I don’t have an informed opinion either way. But, if you are among the many trying to keep genetically modified foods out of your diet, then you’re right to feel weary about soy.

Soy is one of the most abundant genetically modified crops in the world: the first GM soybean crop was planted in the United States in 1996, and since then 85% of the soybean crop in the United States is GM.

If you’re consuming whole or fermented certified organic soy products you shouldn’t be worried, as certified organic foods cannot contain genetically modified crops. Look for the USDA Certified Organic seal on your product.  Another certified seal to look for is from the NON-GMO Project.  All products with this seal are free of GMO.


As always, be aware of greenwashing. Claims like “natural” and “non-GMO” are essentially meaningless because there is no standard definition for these terms and companies do not need to go through a verification process to use them.

So where does GM soy lurk in your diet?

For starters, most GM soybean is fed to livestock throughout the world. In the EU , for example,

Imported soy is predominately used to feed livestock. Without the protein offered by soy, Europe would not be able to maintain its current level of livestock productivity. (GMO Compass)

Many processed foods also contain GM soy.  For example, soy lecithin is an emulsifier  used in many foods to keep them from separating. You’ll find soy lecithin in a range of products including chocolate bars, cereals, cough drops, and even tea.

In other words, avoiding soy products like tofu isn’t going to ensure that you’re keeping GM foods out of your diet.  The best course of action is to check the labels of processed foods you consume, reconsider your consumption of livestock like pigs and poultry, and purchase soy products labeled with the aforementioned certified seals.


After years of intentionally excluding it from my diet I weighed the evidence and ultimately decided I really had nothing to fear. The studies that indicated that soy consumption could negatively effect my health used high doses of isoflavone, so moderate consumption of soy (1-2 servings) per day wouldn’t ever put me at risk. I suppose too much of anything isn’t ever really healthy.  For the last couple of years I’ve been enjoying soy as a healthful source of protein and feel fine!

Illustration created by Elizabeth Stilwell


But, at the end of the day, it’s really up to you to decide what you eat.  It can feel daunting when there is so much information out there, but it’s important to realize that not everything you read is without agenda. So, the next time someone tells you that you’ll get man boobs from eating soy, give them side eye and tell them not to worry!



*Featured illustration also by Elizabeth Stilwell










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Larice January 27, 2016 at 9:04 pm

Excellent post! I’ve been wanting to tackle this issue and all of the misinformation and myths surrounding soy, but I don’t think I could do any better than this! You brought up all the big points, such as eating animal products exposes you to hormones that were in that animals body, which is much more harmful than phytoestrogens. This is something that makes me want to bang my head against the wall when I hear people go on and on about the “dangers” of soy. Thanks for giving such a complete overview (with excellent sources to back it up) and making it fun to read too.

My Kind Closet January 27, 2016 at 9:28 pm

Thanks for reading!! It’s a topic I’ve been wanting to tackle for a while – but it’s so daunting to sift through contradictory information. I think there’s so much more to discuss that I didn’t even touch on. I felt like a lot of the articles I read debunking common fears about soy never really addressed the fact that the fears people have should really be directed to animal based products. I think the dairy and meat industry have done a nice job shielding themselves from those concerns by helping to perpetuate myths about soy. And I’m right there with you banging my head against the wall!! 😉

Larice January 27, 2016 at 9:51 pm

You’re right there is so much information, mostly false, and it’s such a hot topic. I’ve been going over it in my head, mentally sorting it out and making myself dizzy! So it was nice to see you put it all together so succinctly. And you’re right, there isn’t much out there redirecting those fears back on animal products, where they really should be. So glad you brought that up here. Always enjoy your posts, keep up the great work. I’ll be directing others to this one for sure!

My Kind Closet January 27, 2016 at 10:18 pm

Thanks 🙂

Rosy February 2, 2016 at 11:44 am

There’s so much information about it – and I don’t know what’s true or false, so, I don’t eat soy –, and I know that soy is one of most important foods for Asian people, and, personally, I think they don’t have none problems on eating it 😉 but as soy is one of most GMO foods, there’re so much concerns and a hot debate on eating it. There are, including, several studies that prove that GMO fruits & vegetables can lead to an increase on high rates of cancer & infertility. Personally, I think that the problem isn’t with soy, but yes with all GMO foods.


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