When most people think of miso, they conjure an image of a little bowl of soup served at a Japanese restaurant. Miso soup is probably the most popular way to consume miso, but actually, miso is a paste that is widely used for a variety of dishes. Said to be a better alternative than table salt with more flavor to boot, is miso something that would feel right at home in the Paleo lifestyle? Or are its negative effects too great to outweigh any positives?
Making miso itself is quite a process—a base (usually made of soybeans, though any bean will work) is mashed and then combined with a culture called Aspergillus oryzae. This starts off a fermentation process, but what is interesting is that the Aspergillus mixture (often called “koji”) is not a yeast, despite what most people think. Bacteria encourages the beans to ferment, forming a paste that is otherwise known as miso.
This miso paste, which can be used for cooking or made into soup, is a staple in diets around the world—most notably Japan. However, followers of the Paleo diet note that legumes, and especially soy, contain lectins that interfere with blood sugar levels; in other words, they make your blood sugar harder to regulate, so your insulin has to work harder in response. This can lead to insulin sensitivity and metabolic disorder.
Similarly, soy contains phytoestrogens (note the word “estrogen” there), which are a big culprit behind hormonal imbalances. So it seems that perhaps miso, which is soy-based, is not a wise option for those following a Paleo lifestyle.
However, others argue that because soy is fermented and loses many of its toxins in the process, adding it to the diet in judicious amounts is perfectly acceptable. In fact, numerous studies have shown that the sodium in miso actually helps manage blood pressure, not make it worse. Miso actually has a protective effect against high blood pressure, it seems.
Both sides of the argument certainly have their own important talking points, so what is a confused Paleo dieter to do? Thankfully, some Paleo experts weigh in to make the decision a little easier.
What Do Other Paleo Experts Say?
Irena of EatDrinkPaleo says: “A few soy-based ingredients…pass my nutritional acceptance test. These are naturally fermented soy foods such as tempeh, natto, and miso. The reason these particular soy products are not as harmful as tofu or soy milk is that they are produced through a fermentation process, which makes them more easily digestible and reduces the number of present antinutrients such as phytates and lectins. In fact, they are rather healthy and nutritious—they are a great source of probiotics, have high levels of isoflavones (cancer preventative) and a good amount of protein (especially tempeh), minerals and vitamins (especially vitamin K in miso and B12 vitamin in tempeh).”
UltimatePaleoGuide says: “[Miso] may have a positive hormonal impact and help menopausal symptoms, the prostate, lower blood pressure, cholesterol, and diabetes. Again, these benefits are seen when soy is consumed in small quantities from unprocessed and fermented sources such as tempeh, natto, and miso. If you are consuming soy, it should be primarily from those sources mentioned above, in small quantities, and inorganic and fermented form.”
Is Miso Paleo?
Our Paleolithic ancestors did not engage in the process to create miso, so strictly speaking, miso is not a “Paleo food.”
However, fermented foods are actively endorsed by Paleo enthusiasts, including Paleo Living Magazine, for their extensive health benefits. Miso that comes from properly fermented soy is an acceptable addition to a Paleo diet because most of its toxins have been removed during the fermentation process. However, as with any food, try it and see how your body reacts. If you know that you do not tolerate soy well, consider opting out of miso dishes—or better yet, consider looking for miso that is not made from soybeans. Chickpeas and fava beans are known to produce equally tasty miso paste!