Soy: the Good, the Bad + the Ayurvedic Perspective

Soy: the Good, the Bad + the Ayurvedic Perspective

In This Article

Is soy good or bad for you? 

By now, we’ve all been sufficiently confused about the merits and dangers of soy. 

natto soy tofu image

Ancient writings from China suggest the soybean was traditionally considered unfit for human consumption until a soy fermentation technique was discovered. The reason may be that the soybean is uniquely endowed with certain toxic antinutrients that are particularly  hard to digest. As a result, soy is being linked to a host of health concerns.1 

On the other side of the aisle, there is evidence that soy can offer protection against many of the same concerns.2 So, who should we believe? 

Join me as I delve into this heated debate in search of answers. I’ve done my best to include as much research as possible from both sides, before presenting an Ayurvedic perspective. 

What is an antinutrient? 

borlotto beans image

Many plants are protected by toxic antinutrients, which ward off insects and animals that might otherwise eat them. Beans, in particular, are famous for these antinutrients, which, as many of us may know from experience, can make them a challenge to digest. 

Unlike most beans, antinutrients in soy don’t wash or cook off and, according to research by soy opponents, present significant health risks. 

Antinutrients come in a variety of forms. Below I’ve listed the main components of soy that, according to many experts, are cause for concern. 

Breaking it Down

Soy’s troubling compounds + soy supporters’ rebuttal 

Natto is extremely high in vitamin K2, which is rich in fibrinolytic enzymes called NattoKinase.
  • The first troubling group of antinutrients is called phytates. Phytates bind to minerals like zinc, calcium, magnesium, iron, and copper, and may strip them from the body, resulting in mineral deficiencies. Along with enzyme inhibitors, phytates may block the absorption of nutrients from soy, so that any possible benefit is effectively negated.4 That said, soy protein has been used successfully in treating mild and moderate protein-energy malnutrition in some of the world’s sickest children, indicating that the nutrients in soy can be readily available and nutritious.5 
  • Goitrogens are substances that inhibit thyroid function. When the thyroid is compromised, it may enlarge in an attempt to absorb necessary missing nutrients, resulting in a mass called a goiter. Soy inhibits the thyroid’s uptake of iodine, thus driving up thyroid stimulating hormone (TSH) in an attempt to boost thyroid function. In 1991, Japanese researchers reported consumption of as little as 30 grams or 2 tablespoons of soybeans per day for only one month resulted in a significant increase in thyroid stimulating hormone 6—a sign of impaired thyroid function. The Japanese diet is also high in iodine which may naturally mitigate the potential negative effects of a high soy (goitrogen) diet.  Soy supporters argue that in individuals with an otherwise healthy thyroid, no significant changes have been recorded.13 
  • Genestein and diadzen, the isoflavone molecules in soy, inhibit an enzyme involved in thyroid hormone synthesis and may suppress thyroid function as well.7 These isoflavones have also been reported to disturb liver function, reproductive hormones, and fertility.8-12 Experts recommending soy acknowledge this, but argue that in otherwise healthy individuals, studies show soy products have no negative effects on thyroid function.13 
  • In vitro studies suggest isoflavones inhibit synthesis of estradiol and other steroid hormones.14-15 Soy supporters say genistein is actually estrogenic in a positive way. According to this theory, it interacts directly with the notorious HER2 cancer-causing gene, inhibiting its activation by cellular machinery and thereby preventing cancer promotion.16 

Today, soy manufacturers are acutely aware of the antinutrient issue and claim they are removed during processing.3 The only risk, according to them, is when one eats raw soy beans, which many say to avoid. 

Fermentation: The Ancient Solution 

In China, the discovery that soy could be cultured or fermented brought with it a shift in soy’s reputation. While unfermented soy was still avoided as a food, the fermentation process appeared to free soy from the toxic antinutrients and, moreover, actually released some amazing health benefits. During the Ming Dynasty, the fermented soy food natto actually found its way into Chinese Medicine’s Materia Medica, as a nutritional remedy for many health conditions. 

fermented jars of veggies

Today, many experts believe that fermentation is the only way to neutralize the dangerous antinutrients in soy. Perhaps soy may be best classified as a medicine (in its fermented state), rather than a food. 

The Ayurvedic Perspective 

According to Ayurveda, soy is a very hard protein to digest and is not a traditional part of the Ayurvedic diet. In fact, some Ayurvedic doctors are strongly against soy and do not consider it a digestible food. Perhaps the knowledge of its antinutrient content spawned caution in India as well. 

Lemon-Miso Potato and Green Bean Salad

Energetically, it is considered heavy and dulling for the mind. It is generally believed that soy acts more like a nut than a bean, and is therefore pacifying for vata. Still, because of its difficulty to digest and somewhat rajasic or stimulating nature, soy was rarely used medicinally. 

Interestingly, fermented foods are also not favored in Ayurveda, and fermented soy products were never part of the Ayurvedic diet. According to Ayurveda, fermented foods may aggravate vata and are considered tamasic, or dulling for the mind. As a result, fermented foods were not used in Ayurveda and the medicinal nature of fermented soy foods such as natto was unknown. 

In summary, soy is generally avoided in Ayurveda, while some Ayurvedic experts allow it in moderation. Soy should not be your main source of protein. 

Soy in the West 


In the West, soy products have become an industry. From soy milk to soy pills and soybean oil in just about every processed food, Americans are getting way too much soy. Even the promoters of soy encourage moderation and advise that soy not be the major source of protein in one’s diet. 

It can also be very difficult to get non-GMO soy in the west, which may in itself be enough of a reason to avoid it. 

Natto: Ancient Chinese Medicine, Applied 

As I’ve mentioned, traditionally fermented soy foods like miso, traditionally brewed soy sauce, tempeh, and natto are proven safe on both sides of the aisle, and have documented beneficial health properties. Natto, in particular, has been documented and safely used for cardiovascular and circulatory support in the West for the past 20 years. 

k2 supplement lifespa store

Natto is extremely high in vitamin K2 and fibrinolytic enzymes called nattokinase  that has been found to address plaque formation in the heart. 

A fibrinolytic enzyme is an enzyme which prevents the body’s natural process of clot formation. Blood clots, or thrombi, can block blood flow in the arteries of the heart and brain and cause angina, heart attack, or stroke. Protective fibrinolytic enzymes are produced by the body but, as we age, production of these enzymes declines. 

It has been determined that nattokinase actually has four times greater fibrinolytic activity than plasmin, the body’s own endogenous fibrinolytic enzyme.17 

We recommend "97% of Americans are Low in Vitamin K2":

Conclusion: Is Soy Friend or Foe? 

Now that we’ve taken a look at the research from both sides, glanced at soy’s history, and taken into consideration the perspectives of two ancient systems of medicine, what’s the verdict? Here’s my take: 

tofu soy meal
  • Soy should not be your main source of protein. Avoid soy pills. Avoid or reduce soy milk, soy cheese, and other processed soy foods. 
  • A note on tofu: in Japan, tofu is significantly more cultured with a much stronger taste than it is here in the States. American tofu should be eaten in moderation. 
  • Enjoy traditionally fermented soy products such as miso, tempeh, natto, and traditionally brewed soy sauce. Still, make sure even these products are organic and non-GMO: this very important! 
  • Consider including natto either as a food in your diet, or the enzyme nattokinase as a supplement, to maintain optimal health of your arteries. 

What do you think about soy? 

Thank you for visiting, where we publish cutting-edge health information combining Ayurvedic wisdom and modern science. If you are enjoying our free content, please visit our Ayurvedic Shop on your way out and share your favorite articles and videos with your friends and family.

Dr. John


  1. Daniel, KaaylaThe Whole Soy Story. 

24 thoughts on “Soy: the Good, the Bad + the Ayurvedic Perspective”

  1. I am happy to find this information on soy from an ayurvedic perspective. I’ve known for years that I can’t eat soy. I have heard of people having soy allergies but my reaction to soy is extreme and goes beyond the typical allergy symptoms that western doctors list; just 1/8 of a teaspoon of soy oil is enough to make my ears start ringing very loudly, cause insomnia and make me feel like I’ve got a tremor throughout my body. A high dose of soy that I ate unwittingly, it was hidden in something)once caused such a reaction that my husband had to call emergency services. I was just talking to a friend about soy and told her that for me, personally, it feels *very* anti-prana like. It’s incredible how soy has been pushed on the western world under the false premise that Asians eat loads of soy. That’s simply not true. Thanks for this info and I would love to read some more Ayurvedic sources about soy if you have any.

  2. According to the soy industry’s own stats, for consumption in China, Japan, Indonesia, Korea and Taiwan, the daily consumption of soy ranges between 9.3 to 36 grams of soy products (not just soy protein but total soy food!). Comparing that with a cup of tofu, which is around 250 grams that an American will eat in tofu dishes or tofu burgers, etc. Asians eat a fraction of what Americans are eating in terms of soy.

  3. What if you have breast cancer that is 90 percent estrogen and progesterone positive? It scares the fool out of me, and I’ve been avoiding all soy.

  4. I was suprised to hear you say fermented foods are not “favored” in Ayurvedic tradition. There are hundreds of traditional recipes for fermented pickles, everything from chillies to jackfruit! Not to mention the fermented rice and lentil batter that is used to make dosas, idlies and uttapams! Also lassis and paneer are fermented. In such a hot and humid environment, before refrigerators, fermentation would have been essential to prevent food spoilage.
    Of course Ayurveda always cautions against overconsumption of anything but to claim it teaches avoidance of fermented foods is simply wrong.

    • Yes, I was surprised to hear that, too. I don’t know if there is a culture anywhere in the world that doesn’t consume one type of fermented food or another.

  5. Isn’t it true ro say that most plant foods have anti nutrients especially plants like spinnach, beet greens, beans, seeds, nuts, lentils etc? Why is the research between the ‘eat’ and the ‘eat not’ so disparate with each group proving by the latest research that their point is correct? Who do you trust? What I would like best of all is for some of the excellent questions in the lifespa blogs to be adressed so everyone can read the answers? I have read and commented in three today and none have had answers.

    • You are absolutely right that there is conflicting research everywhere you look on almost every food. The big thing is to begin an awareness yourself on how these different foods make YOU feel. When certain, harder to digest, foods make you feel worse–take that as an indication that you may want to work on strengthening your digestive fire. Thank you for the comment!

  6. Thanks , I have recently been looking for info about this subject for a long time
    and yours is the best I have found out till now.
    However, what about the bottom line? Are you sure in regards to the supply?

    • In short, the main point here is to understand that soy is a very difficult protein to digest. Consuming organic and non-GMO sources of soy is important. Elderly and young children would be advised not to consume soy in an effort to support a healthy digestion. Be well.

  7. Thank you very much Dr. John Douillard. Your work is great. I really appreciate it.
    I wish you and your family the best. Greetings from Germany

  8. Thanks for the information .it is first time that I read..I am from India..we are promoting homemade soyamilk as nutrition for masses.Mahatma Gandhi called soyabeen as golde, bean,
    However much research is needed to make it digestible .perhaps addinu spices like cummins.ginger.turmeric can give simpler solutions.
    Many people in this world cannot afford proteins . so some further research is needed.
    We manufacture and market online some soya products and some sprouted see vivafoods on Amezon or flipkart .
    Padmakar deshpande .
    Pune india

  9. Is Soy Lecithin in supplements acceptable? I am looking for a Vitamin E supplement without soy. Thanks for the excellent information.

    • Hi Gloria,

      I tend to avoid anything with soy in the ingredients unless I am eating some type of fermented organic soy product.

      Be Well,
      Dr. John

  10. I have cardiovascular disease with calcified arteries. I have been taking vitamin K2 (Mq7) for a few years hoping to stop. Or reduce calcification. I have recently purchased some Nattokinase, but found that K2 has been removed. Is there any advantage to taking a supplement like this without the K2 included? I am vegetarian, I don’t eat much soy at all, and I live a healthy lifestyle with exercise.

    I appreciate your articles and continue to read them regularly.

    • Hi Richard,

      I like the combination of natto and K2 either in one supplement or separately. Hope that helps.

      Be Well,
      Dr. John

  11. Hi John,
    What are your thoughts on menopausal women consuming a moderate amount of soy products in order to increase estrogen. I have also noticed companies promoting soy isoflavones for menopause – would that be a no-no?
    Thank you!

    • Hi Holly,

      The science is mixed. I would suggest moderate amount of sprouted tofu or fermented tofu but not on a daily basis.

      Be Well,
      Dr. John


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