Is Soy Healthy?

In her weekly column, licensed nutritionist Nonie De Long tackles the sticky question of soy products…

Dear Readers, 

This week’s column features the first of the top ten nutrition questions I get asked. Tune in over the following 9 weeks for the remainder. If you are confused by conflicting nutrition advice or have lingering questions, this may help clear some of them up. If you don’t see your question answered, send me an email with your query and if I can I’ll feature it in an upcoming article. 

First let’s address the elephant in the room. How can you know if my nutrition information is superior to anyone else’s if there is controversy. (When it comes to soy, I assure you there is.) The best advice I can give if you’re not a nutrition professional and don’t want to read every study I link to and then cross reference it is to take your time reading what I share, think about it, go to other trusted sources to see if they may have an opinion on the issue, then TEST the information I share in your own life. This is how I advise clients to test any nutrition information they get and this is how I come to write what I do. I study then cross reference, then think about and look for answers to questions that come up, then test the conclusions I come to with my own diet. After that, I test my conclusions in my clinical practice and read notes from other practitioners to stay abreast of what they observe. This is how we can know if something benefits or hinders our health.

Usually with dietary changes there is a fairly immediate impact from frequently consuming any food product. If you aren’t able to discern that impact you may need professional help. Being able to listen to how your body responds to foods and learning how to understand those responses is a great skill to develop and a professional nutritionist will be able to help you on that journey.

One of the most common questions I get is around the health of soy products, often from those wishing to cut down on meat and find an alternate source of protein. I also get the question from women in menopause who are looking for ways to mitigate the hot flashes and sleep related symptoms. It can be difficult to figure out the data around menopause and soy products. Additionally, with the soaring cost of groceries and concerns with the sustainability of meat consumption, soy as an alternative may be something on many people’s minds. So let’s do a deep dive to better understand the facts about soy.

Nutritional Profile

First, let’s do an overview. Soy is a legume containing all the essential amino acids and is readily available in a number of products so it stands to reason that people have interest in it. In addition to protein, soy is rich in B vitamins, fibre, and potassium and magnesium (if the soil contains it). If you aren’t aware, soy can be found as a milk alternative, tofu, tempeh, edamame beans, miso paste, meat alternative products (weiners, tofurkey, burgers), vegetarian texturized proteins, soy sauce, many flavourings, and infant formulas. These are marketed heavily toward the vegetarian and health conscious community and it’s an ever growing market. 

Soy for Menopause

Soy is particularly interesting as a food for menopausal women, since we know Japanese women consuming traditional diets rich in soy don’t experience the same menopausal symtpoms that North American women do. It’s long been theorized that this is because of the isoflavones in soy. These phytoestrogens (plant estrogens) are weaker than human estrogen but can bind to estrogen sites in the body. This means they have the power to mimic and alter estrogen levels and responses in the body.

What is less known is that they are toxins the plant contains to act as a natural pesticide against insects, producing sterility. Keep this in mind as we discuss soy further.

In some studies, soy has been found to be effective in reducing menopausal hot flashes, without the risks associated with hormone replacement therapy. However, studies vary widely on this issue, depending on dosage and other variables.

Some studies suggest it may be the protein in soy instead of the isoflavones that actually make the difference in outcomes. But it’s hard to draw conclusions because nobody seems able to agree.

When considering studies like this it can be difficult to extract clear data. Is it an animal or human study? What type of soy is used - whole food or food extracts, organically grown or GMO? What dose of these is given? Is it enough to be therapeutic? What are the hormone levels of study participants to begin with? What are the other lifestyle factors of study participants? 

Even the theories we start with may be flawed. For example, do Japanese women experience fewer hot flashes due to their soy intake or due to other specific dietary and lifestyle habits, like their consumption of fermented foods and their lack of processed foods, for example? We know processed foods increase inflammation, which impacts menopausal symptoms, and we know fermented foods decrease inflammation and help modulate hormone responses in the body. How might all of these factors interact? These questions remain difficult to answer. 

In traditional Asian culture, soy was consumed in fermented condiments and fermented bean products. It was not consumed at all like it is promoted or prepared today.

From Harvard’s School of Public Health: “There are many factors that make it difficult to construct blanket statements about the health effects of soy.” Super helpful, right?

The bottom line on soy in menopause: some women feel it makes a great difference to their menopausal symptoms, while others do not. I’m sorry the data isn’t more clear than that. Given the concerns about how soy is grown and manufactured, and inconsistencies in studies, I caution women wanting to add it to their diets for menopausal relief. There are herbal and homeopathic remedies that work very effectively for this purpose and do not carry any risk.

To try soy for menopause, I recommend reading the entire article first, ensuring iodine intake is sufficient first. The best products to try are organic and non-GMO, fermented soy, which has additional benefits. I will get into the reasons for these recommendations below. 

Soy and Cancers

Soy products have been much maligned as causing cancers. Additional research has yielded only a few studies to support this.

Eating soy may turn on the genes related to cancer growth

More often, though, soy products have been shown in studies to reduce the incidence of breast cancers. “Several large, human studies—in which thousands of women have been followed for many years—consistently show that compared with women who do not eat soy, women who regularly eat soy have lower breast cancer risk. Some of these studies also suggest that breast cancer survivors who consume soy foods have a lower risk of breast cancer recurrence compared with survivors who avoid soy.” Soy has also been shown to be protective of bone health in cancer survivors in studies.

Now this could be because of the consumption of soy, or it could be because those who regularly consumed soy were also taking other lifestyle and dietary measures which reduced their risks of developing breast cancer. Nutrition studies are tricky. It would seem, in the least, that soy intake is associated with lower risks for breast cancers. How much lower? I can’t be certain given the range in the studies.

Read on to understand why I still can’t recommend soy as a staple.

Soy and Hormones

On the flip side, soy intake may lower sperm count and testosterone in males, including inhibiting testicular development in neonates, with later implications for testicular function. It’s been shown that soy can have an estrogenic effect on males, hindering growth and in rare cases, contributing to gynecomastia (breast development). These are interesting considerations given the trends we’re seeing in gender dysphoria. I don’t recommend it as a staple food for males or pregnant females for these reasons. 

Rodent studies suggest that eating large amounts of the estrogenic compounds (isoflavones) in soy reduces fertility in females and could trigger premature puberty. It’s been speculated that this could have to do with the spike humans have seen in these areas of pathology. There is no denying that our female children are reaching puberty earlier and fertility is a growing problem for many in developed countries. The data is not in yet on these related to soy.

Soy for Babies and Children

“Children receiving soy formula as their only food take in over 10 time the levels of isoflavones on a body weight basis than the amount shown to cause thryoid suppression in adults after three months and about eight times the levels of isoflavones on a bodyweight basis as the amount shown to cause hormonal changes in adults after just one month.” (source)

“It is clear that the isoflavones in soy infant formula are well absorbed by the infant. Babies on soy formula were found to have levels of serum estrogens at 13,000 -22,000 times greater than those in infants who had been breast fed or given milk-based formula.” (source)

In babies soy often creates allergies and nutritional problems, including sometimes very serious digestive issues.

Additionally, soy consumption in children has been linked to an increase in Kawasaki disease, an autoimmune condition that causes inflammation in arteries and can result in irreversible and devastating damage to the heart. The hormonal impacts of soy on developing babies is known to impact testicular development and later function. Given all of this, I can’t recommend it as an optimal alternative to breast milk.

For healthy homemade infant formula recipes, go to the Weston Price Foundation, here.

Soy and Thyroid Health

It’s widely debated that soy can impact thyroid health with studies aplenty to debunk this. However, do remember that the industries who fund studies are very interested in promoting the products they sell - and soy is a big one. If you read closer you will note that the studies promoting soy as healthy for thyroid function repeatedly conclude that where iodine is sufficient, soy doesn’t interfere with thyroid function.

There are studies that dispute this and feel much more investigation is needed:

https://pubmed.ncbi.nlm.nih.gov/12060828/

Clinically I have regularly seen regular soy intake correlated to the development of thyroid issues. Given that experts feel almost everyone in North America is deficient in iodine and that in Japanese culture a diet high in iodine diet was paired with soy intake, it might not be wise for everyone to increase their intake of soy without first looking at their iodine levels. Thyroid disease is rampant in North America today and often undiagnosed until it’s extremely far gone. It has an incredible impact on overall health and wellness.

Fermentation

Some nutrition experts advocate limiting soy products to those that are fermented to reduce the anti-nutrients present in the bean. I would agree with this recommendation. In Japanese culture this is typically how soy products were prepared and consumed. Miso, natto, tempeh, and traditional soy sauces are all fermented products. 

In case you’re not aware, beans all possess anti-nutrients. The anti-nutrients in soy act to block mineral absorption - especially zinc. And even if you don’t eat soy it’s hidden in many processed foods so the likelihood is that you’re being unintentionally exposed. However, fermentation releases the anti-nutrients and makes soy a super healthy food that not only has nutritive value but also improves the gut biome.

Cultivation

Could some of the problems with soy also have to do with how the crop is cultivated today? 

Soy is the number one genetically modfified crop in the world. In 2018, GMO soybeans made up 94% of soybeans planted in the U.S. “GM crops are grown around the world by approximately 17 million farmers, most of them in developing countries. In total, more than 70 countries import or grow GMOs....  As of 2019, the top five countries growing GMOs in terms of crop area are the United States, Brazil, Argentina, Canada and India.”

The rational is that genetic modification of organisms improves the yield and nutrient content of the products. It’s also promoted to reduce costs and reduce the need for pesticides. However, according to one Berkely biotech specialist, “numerous studies have shown no nutritional differences between commercially available GMO and non-GMO foods. She continues…”genetic modification can improve the nutritional content of some foods, for example, low linoleic acid canola oil that can reduce trans-fat content.” As an aside, if you follow my work regularly you already know that using natural fats reduces trans-fat content to zero without the use of genetic modification.

Forbes reported in 2013 that adoption of GM technology did not result in less herbicide use, but more. In a paper prepared for presentation for the 2015 Agricultural & Applied Economics Association and Western Agricultural Economics Association Annual Meeting, in San Francisco, CA, July 26-28, Purdue University researchers shared that “if all American farmers switch to growing non-GMO crops, food will cost more, crop yields will be lower and more land will be needed to grow our food.” The paper was summarily disregarded and fact checked into oblivion.

We humans like to think our technology can improve all systems, but things like soil biome health and the health of the surrounding ecology in light of massive clear cutting and mono-cropping such as is employed in GM agriculture are not factored into our equations. Time will teach us if this is a good system or not.

Social/ Economic Impact

In India, where GM crops were sold en-masse to small farmers as a way to drastically increase yield and salary, more than 296,400 have committed suicide. By 2008 the number had soared to over 1,000 farmers per month. PR reps for the related stakeholders have done much to shift the blame to the small farmers whose lives have been destroyed, but independent and unbiased journalists and humanitarian organizations who have travelled to the region have confirmed the relationship to GM crop failures and debt.

In fact, Prince Charles spoke out about it, branding it 'GM Genocide' and saying “it had become a 'global moral question' - and the time had come to end its unstoppable march.” Vandana Shiva, physicist, ecologist, and world renowned environmental leader, who has seen the devastation in her native India with her own eyes, has been speaking out about this publicly and through her books and non-profit work for some time. You can hear one such interview here. Her documentary also touches on it. 

You may ask, what does the health of soy products have to do with the cultivation of soy products? But everything is connected. We cannot dump pesticides on our land without it ending up in our tap water. We cannot expect these pesticides don’t alter the microbiome of the soil in a profound way and that an altered soil biome won’t impact us. We cannot expect it to not impact our pollinators and that such an impact won’t then impact our food supply. 

Sure, for a time, soil treated thus may produce bountiful crops, but over time it remains to be seen what can be grown when soil is too far gone to be bolstered with liquid fertilizer. Is it sustainable to repeatedly till and spray soil with ever stronger liquid fertilizers and pesticides? Can this produce foods as delicious and nutritionally dense as the natural systems it replaces?

In answer, I invite you to try a GM tomato alongside a home grown one using organic soil and growing methods and weigh in. What do your taste buds tell you? Blindfold the kids, line them up, and try it - a simple and fun home experiment my father liked to with home grown food when I was a kid. I also invite you to place a sample from both home grown and GM tomato crops on your counter and watch what happens. In my home the GM tomato will deteriorate much more quickly than the garden grown one. I invite you to determine if there is a difference for yourself. 

Summary

The takeaway on soy is that small amounts may be healthy if it’s organic, non-GMO, and fermented and there is sufficient iodine intake. It may not be healthy or adviseable for men and I certainly can’t recommend it without further study as an optimal staple food for infants, pregnant females, and children. 

I hope this is helpful. Tune in next week for the lowdown on whether organic food is healthier. As always, if you have a question for the column, you can write to me at nonienutritionista@gmail.com. If you want clinical care or to know more about what I do, you can find me online at hopenotdope.ca.

Namaste!

Nonie Nutritionista