Is Miso Healthy? Here's What a Dietitian Has to Say
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 and umami flavors add richness to a variety of dishes.
Pictured Recipe: Miso Vegetable Soup
What also makes miso a globally popular ingredient in recent years are its potential health benefits. A recent study from Japan suggested 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 is miso, how it is 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. Specifically, 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 stands for 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 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, specifically, soybeans are used to feed the fungus strain before 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. Moreover, different regions in Japan produce locally unique miso that varies in color, flavor and texture, based on its 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.
Miso Nutrition Facts
For every tablespoon (17 grams) of miso, there are:
- Calories: 34
- Fat: 1g
- Sodium: 634mg (28% DV)
- Carbohydrate: 4.3g
- Fiber: 0.9 g
- Protein: 2.2 g
Health Benefits of Miso
Miso is often eaten in small amounts, so the health benefits they offer may not be substantial. Still, including miso as a part of your regular eating pattern might help you reap these health benefits.
1. Improve digestion
When 70 percent of the immune system is located in the digestive tract, it is not surprising that keeping a healthy gut is a priority. Eating fermented foods such as miso may improve digestion, reduce gas, bloating, constipation and diarrhea. Research suggests that the fungal strain found in miso may reduce the risk of inflammatory bowel disease as well. Like other plant-based foods, soybeans have antinutrients present, which could potentially reduce the body's ability to absorb nutrients. However, fermentation may reduce the amount of antinutrients present in soybeans, making them easier to digest.
2. Support a healthy immune system
Consuming fermented foods like miso may also support a healthy immune system by protecting the body against harmful microorganisms. 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.
3. Reduce the risk of stomach cancer
A high salt diet is possibly linked to the increased risk of stomach cancer, but eating miso regularly may not contribute to such risk. When miso was compared to pickled foods and processed meats in one study, the former did not increase one's risk of stomach cancer, despite its high salt content. The finding was echoed by a different research study, which suggested that frequent consumption of soybeans, including miso, may be associated with the reduced risk of stomach cancer. This could be possibly due to soy isoflavones, a group of beneficial compounds present in soybeans that may have anti-inflammatory and antioxidant properties.
Potential Drawbacks of Miso
While miso is a nutritious food with some potential health benefits, it also has some drawbacks to consider.
1. High Sodium Content
Miso is made using a significant amount of salt. According to the USDA Food Database, one tablespoon of miso already 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 are at risk for heart disease, such as high blood pressure.
2. 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. Under food labeling requirements, manufacturers must state clearly in the food package that soy or a soy-based ingredient is present.
3. Gluten Sensitivity
Some miso may include barley, which contains a small amount of gluten. If you have been clinically diagnosed with gluten sensitivity or celiac disease, you want to steer away from barley-based miso. Remember 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. 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, where 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.
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.