Is Miso Healthy? Here's What a Dietitian Has to Say (2024)

Pictured Recipe: Miso Vegetable Soup

Have you noticed that you are offered a bowl of hot miso soup when you order sushi at your local Japanese restaurant? Miso, a fermented soy product in the form of a paste, is one of the staples in the traditional Japanese diet. It is widely used as a condiment and an ingredient in Japanese sauces and soups.

In recent years, miso has gained traction in Western cuisines, where chefs and food enthusiasts have adopted this Japanese ingredient into their cooking. Its bold umami flavors add richness to a variety of dishes.

What also makes miso a globally popular ingredient in recent years are its potential health benefits. A 2020 study in The BMJ from Japan suggests that eating fermented soy products, such as miso, may be one of the reasons for better overall health and longevity. Here we take a deep dive to explain what exactly miso is, how it's made and its health benefits.

What Is Miso?

Miso is a traditional Japanese soybean paste made by the fermentation of three ingredients: cooked soybeans, molded grain and salt. The mold, Aspergillus oryzae, is used in fermentation. This is the same mold used to make soy sauce and the Japanese alcoholic beverage sake.

To make miso, the mold is added to a steamed grain, usually rice or barley, where the grain is used as food to feed the fungi, allowing them to grow and multiply for several days. Together, they form an ingredient called koji, which means fermentation starter in Japanese. Then, the fermented grain is added to the cooked soybeans and salt before the blend is put away for fermentation for several months. When the fermented mixture is ready, it will be mashed, packaged and sold.

Generally, there are three types of miso: rice miso (kome-miso), barley miso (mugi-miso) and soybean miso (mame-miso). For soybean miso, soybeans are used to feed the fungus strain before being mixed with soybean malt and salt. You can also find a fourth type of miso in Japan called awase miso, which is a blend of the three types of miso. Different regions in Japan produce locally unique miso that varies in color, flavor and texture, based on local ingredients, climate, environment and flavor preferences.

Miso offers blends of complex flavors, from sweet to umami, salty, bitter and sour. Depending on how much salt and fermented grains are used, the miso flavor profile can range from mild (ama miso) to sweet (amakuchi miso) and strong (karakuchi miso). The color of miso can also vary from white to yellow to red, depending on the ingredients used and the fermentation and aging processes. The longer the miso is left for aging, the darker it becomes.

You can find miso in your local Asian or Japanese markets and health food stores. Once the tub of miso is opened, it is best to store it in the fridge. Note that the longer the miso is kept, the darker its color becomes due to aging.

Health Benefits of Miso

Miso is often eaten in small amounts, so its health benefits may not be substantial. Still, including miso as a part of your regular eating pattern might help you reap these health benefits.

Improved Digestion

Having a healthy gut is a priority for many reasons, including a strong immune system, reduced inflammation, quality sleep and mental health. Eating fermented foods such as miso may improve digestion, reduce gas, bloating, constipation and diarrhea.

Healthy Immune System

Consuming fermented foods like miso may also support a healthy immune system by protecting the body against harmful microorganisms, per a 2022 review in Nutrients.

According to a 2023 article in Probiotics and Antimicrobial Proteins, scientists believe that the beneficial bacteria in fermented foods produce byproducts called postbiotics. Postbiotics may have immune-supporting properties, but more research is needed to confirm their health benefits.

Reduced Risk of Stomach Cancer

While eating too much salt over time may increase your risk of stomach cancer, regularly eating miso may not contribute to such risk. When miso was compared to pickled foods and processed meats in one 2021 review published in Frontiers in Nutrition, miso did not appear to increase one's risk of stomach cancer despite its high salt content.

This could be possibly due to soy isoflavones, a group of beneficial compounds present in soybeans that may have anti-inflammatory and antioxidant properties.

Miso Nutrition Facts

According to the USDA, 1 tablespoon (17 grams) of miso contains:

  • Calories: 34
  • Carbohydrate: 4.3g
  • Fiber: 0.9 g
  • Added Sugar: 0g
  • Protein: 2.2 g
  • Total Fat: 1g
  • Saturated Fat: 0g
  • Sodium: 634mg (28% DV)

Potential Drawbacks of Miso

While miso is a nutritious food with some potential health benefits, it also has some drawbacks to consider.

High Sodium Content

Miso is made using a significant amount of salt. One tablespoon of miso provides almost one-third of your recommended daily sodium intake. The amount of sodium present may also vary among brands and types of miso.

The American Heart Association recommends consuming no more than 2,300 mg of sodium, with the aim of no more than 1,500 mg per day for adults. You may want to eat miso in moderation by adding it sparingly in your day-to-day cooking, especially if you are watching your sodium intake or have high blood pressure, which increases your risk of heart disease.

9 Easy Ways to Cut Sodium in Your Diet

Soy Allergy

Because miso is made with soybeans, those who are allergic to soy should avoid miso and other soy-containing products. Miso may also be used as an ingredient in other packaged products, so it is best to read the ingredients list and label to ensure that what you're buying is free of soy.

Gluten Sensitivity

Some types of miso may include barley, which contains a small amount of gluten. If you have a gluten sensitivity or celiac disease, you want to steer away from barley-based miso. It's important to note that just because the miso paste you purchased is free of gluten-containing grains, it could be made in a manufacturing facility that also produces gluten-containing miso. So if you are super sensitive to gluten, make sure to read the ingredients list and choose a product that has specifically stated it is safe for those who follow a gluten-free diet.

How to Use Miso

Miso is a highly versatile ingredient. You can use small amounts to marinade steak and skewers, glaze a broiled salmon, dress your salads and use in stir-fries and noodle soups. Our Orange Miso Sauce is also perfect for sautéing turkey.

Have a sweet tooth? Miso can also be added to desserts, such as our Miso Apple Bars, creating a unique flavor profile where umami meets sweet.

The Bottom Line

A little dose of miso goes a long way to please your taste buds. It also may contain health benefits like improving digestion, supporting healthy immunity and even reducing risk of certain cancers. Reap the benefits yourself by making one of our miso recipes today.

Is Miso Healthy? Here's What a Dietitian Has to Say (2024)
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