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Soy 101: The Dangers and Side Effects

Are you confused about soy? Wondering what effects all those soy products could be having on your health? Not sure if the soy protein in your cupboard is safe to use in your smoothies? Do you want to avoid soy, but aren’t sure where to start?

Your concerns are valid! 

Soy and soy products are prevalent in every grocery store aisle, and many packaged foods today contain soy. For so long, soy has been touted as a safe alternative to dairy products, especially for those who can’t tolerate lactose or are allergic to dairy. 

However, researchers aren’t convinced that soy is all it’s cracked up to be, so we’re taking a look at the potential side effects soy can have on your hormones, gut health, thyroid, and more. 

What is Soy?

Soy and soy products are derived from soybeans, a member of the legume family. Soy is used to produce a number of food products, including:

  • Infant formula
  • Soy milk
  • Soy flour
  • Tofu
  • Tempeh
  • Soy sauce
  • Most processed foods

Because soy can be used to emulsify fat and bind with water, keeping food products moist without adding unnecessary ingredients, it is widely prevalent in many processed foods and even used in cosmetics, soaps, and craft materials. 

The Effects of Soy on the Body

Soy has been a hot topic of debate amongst medical professionals for a few years, with extensive research being done about the effects of soy on our bodies. Previously, soy products were seen as a safe, healthy protein alternative to meat and dairy products for vegans, vegetarians, or those allergic to meat or dairy.[1] 

But as research has shown, soy has numerous adverse effects on the body. Because it is commonly used in many household goods and preserved foods, our exposure to soy-containing products has led to an increase in serious health concerns including:

  • Hormonal imbalance
  • Thyroid issues
  • Digestive problems
  • Reduction of nutrient absorption in the body

Soy and Hormonal Imbalance

One of the biggest health crises facing women (and sometimes men) today is a hormonal imbalance. Soybeans are high in phytoestrogens, a plant compound with an estrogen-like chemical structure. While phytoestrogens are sometimes used in natural hormone replacement therapy, a diet high in phytoestrogens can lead to hormonal imbalance.[2] 

Because phytoestrogens have a similar chemical structure to estrogen, they are able to mimic the function of estrogen in the body because the hormonal receptors in your body mistake the phytoestrogen for the estrogen produced by the body. Estrogen is needed in a woman’s body for many functions, including ovulation, healthy pregnancy, healthy energy levels, maintaining restful sleep, and preventing skin aging.[3] 

However, if the body perceives too much estrogen in the system (due to the high amount of phytoestrogens in the body), this imbalance can lead to estrogen dominance or other forms of hormonal disruption.[4] 

This hormonal imbalance, including disrupted endocrine function, can lead to infertility and can promote breast cancer in adult women. Especially for women of child-bearing age, it’s important to reduce soy in both the diet and lifestyle factors. 

Soy and Hypothyroidism

The phytoestrogens found in soy also act as potent antithyroid agents, inhibiting the function of the thyroid and leading to increased risk of hypothyroidism.[5] 

In one study, infants who consumed soy formula had a significantly higher likelihood of developing autoimmune thyroid disease than infants who consumed only breast milk.[6],[7] Researchers agree that children being fed soy formula should be monitored for thyroid issues.[8]

Additionally, soy has goitrogenic properties, which means it contains components that cause the swelling of the thyroid.[9],[10] Soy slows down the thyroid’s ability to absorb iodine, the chemical element the thyroid needs to produce hormones.  

When the thyroid can’t keep up with the demand for hormone production, it tries to work harder, leading to more swelling and increasing the risk of hypothyroidism.[11] This negative cycle continues indefinitely until the antithyroid agents are removed from the body.

If you are suffering from hypothyroidism, it may be best to avoid soy, especially if you are on thyroid medication, as it is believed to inhibit the body’s ability to absorb the medication.[12],[13]

Soy and Digestion

In a study funded by the National Center for Complementary and Alternative Medicine (NCCAM), participants were monitored for adverse effects of soy on the kidney, heart, and digestive functions. The study found that the participants with the highest amount of soy in their diets were most likely to have digestive complaints, with the most common symptoms being diarrhea, nausea, and flatulence.[14],[15] 

Soy, Phytic Acid, and the Absorption of Vitamins in the Body

Phytic acid, often referred to as an “anti-nutrient” due to its negative effect on nutrient absorption, is a plant compound found in many seeds, nuts, and legumes, including soybeans. But how does this potent anti-nutrient impact you?

High levels of phytic acid in soy reduce the assimilation of vital nutrients such as calcium, magnesium, copper, iron, and zinc.[16],[17] Functionally, this means that your body can’t absorb the necessary vitamins and nutrients you are feeding it.

In many cases, it is possible to soak or sprout seeds to reduce phytic acid content. However, the specific phytic acid in soy is not neutralized by these preparation methods. Instead, it’s best to avoid soy altogether.

Fermented Soy and Vitamin B12

Fermented soy products like tempeh were once thought to be relatively high in Vitamin B12, a vitamin necessary for the formation of blood cells, and was once considered a safe dietary source of this vitamin.[18] 

Unfortunately, recent research has shown that the specific B12 analogs in soy are not absorbed in the body and actually increase the body’s requirement for B12.[19] In fact, the Vitamin B12 contents of soybeans are low or undetectable, and the fermentation process used to create tempeh does little to increase the amount of this necessary vitamin.[20]

Avoiding Soy: Next steps

With all the hype surrounding soy, and given that soy is prevalent in almost all processed foods (especially the ‘health’ food products you see lining the shelves), it can be hard to completely avoid soy in your diet especially if you don't have time to read labels.

There are a few things you can do to make avoiding soy easier on you and your family.

  1. Cut out any obvious soy-containing foods from your diet. Avoid soymilk, tofu, edamame, soy sauce, tempeh, or soy flours. 
  2. Avoid all processed foods. Once you cut obvious soy foods from your diet, you could still be consuming large amounts from the processed foods you eat. Even so-called ‘healthy’ processed options often contain soy. Instead, opt for a clean, whole-foods based diet and avoid processed foods altogether. 
  3. Empty your cabinets of any products containing soy. Take the time to read the labels, and mentally note or jot down brands that don’t contain soy. If the products aren’t in your pantry, you won’t be tempted to reach for them, and you’ll also get used to cooking without them more quickly. 
  4. Avoid soy protein powders. Soy Isoflavones are prevalent in many protein supplements. Instead, try a soy-free collagen-based protein powder in your smoothies or shakes. 
  5. Reset your system. If you’ve been ingesting soy or other toxic foods for a while now, it might be time to try a reset. The NativeBody Reset is a 30-day blueprint designed to help cleanse your body of the toxic foods and lifestyle factors like soy products we encounter in our modern world. It’s not a diet, but a reset of your whole body, diet, and lifestyle, designed to help you move forward and create long-lasting change.

What do you think? Are you ready to ditch soy and commit to changing your diet and lifestyle for the better? Here at NativePath, we don’t want to just tell you what to do – we want to help you implement the habits, foods, and mindset to help you become the healthiest version of yourself. 

That’s why we created the NativeBody Reset – to kickstart your health journey in a way that’s sustainable. Resetting the body is the best way to undo the negative effects of soy and other harmful toxins that are prevalent in our modern world. In this flexible, customizable program, you’ll learn how to:

  • Detoxify your lifestyle and diet
  • Balance your hormones
  • Regain your energy
  • Incorporate more movement into your daily routine
  • Join a community of like-minded individuals also committed to true, whole body wellness
  • And so much more!

If you’re ready to commit to a total lifestyle and body transformation, this reset is for you. Join us today and find out what sustainable, healthy changes look like in your body!


  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5793271/ 
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270274/
  3. https://www.ncbi.nlm.nih.gov/pubmed/11705091 
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139237/
  5. https://www.ncbi.nlm.nih.gov/pubmed/9464451
  6. https://www.ncbi.nlm.nih.gov/pubmed/2338464
  7. https://www.ncbi.nlm.nih.gov/pubmed/7596704
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2661347/
  9. https://www.westonaprice.org/health-topics/soy-alert/studies-showing-adverse-effects-of-dietary-soy-1939-2008/
  10. https://www.ncbi.nlm.nih.gov/pubmed/18558591
  11. https://www.westonaprice.org/health-topics/soy-alert/studies-showing-adverse-effects-of-isoflavones-1950-2010/
  12. https://www.thyroid.org/documents/ctfp/volume4/issue6/ct_patients_v46_12_13.pdf
  13. http://www.btf-thyroid.org/information/108-thyroid-and-diet-factsheet
  14. https://www.ncbi.nlm.nih.gov/books/NBK11870/
  15. https://www.ncbi.nlm.nih.gov/pubmed/10499479 
  16. https://www.ncbi.nlm.nih.gov/pubmed/1503071
  17. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4325021/
  18. https://www.ncbi.nlm.nih.gov/pubmed/2893065
  19. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257642/
  20. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4042564/

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Medical Disclaimer
This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Dr. Chad Walding nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement, or lifestyle program.

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