There is a lot of controversy surrounding soy and soy products like natto. With all the conflicting claims from researchers and health experts, it’s no wonder many people wonder if soy is good or bad for your health.

The answer is: it depends. Marketing geniuses touted soy as the miracle health alternative to just about everything. In most supermarkets you will find soy milk, soy protein, soy oil, soy lecithin and even soy soap. Unfortunately, many forms of soy aren’t necessarily as healthy as food manufacturers would have you believe.

The problem is that the soy you see in all of these foods is not the traditional culture of Japan. In fact, the majority of soy you find in grocery stores is actually genetically modified (GMO), produced in a different way, and doesn’t have the same nutritional benefits.

However, when you ferment soybeans, you get a completely different product that has an entirely separate set of nutrients. This is why, when it comes to soy, the safest and best way to consume it is to consume fermented foods like miso, tempeh, or natto. But what is natto and what impact can it have on your health? Let’s go.

What is natto?

Natto is a traditional food that is usually eaten for breakfast by Japanese people, along with miso soup, fish and rice. Tofu, tempeh, miso, and natto are all whole, soy foods. However, unlike many other soy foods, natto is fermented, which explains many of its health-promoting properties. It is made by soaking whole soybeans, then steaming or boiling them, and then adding Bacillus subtilis bacteria to the mixture. It is then left to ferment for some time.

Natto is known to be a rather acquired taste, probably due to its unique smell and texture. So what does natto taste like? It has a distinct, bitter flavor, and for many people the smell of ammonia can evoke a mixture of old socks and cheese. As for its texture, it resembles a slimy, stringy and sticky little bean, which further adds to its unappealing character.

People generally have very strong feelings about natto: they tend to love it, hate it, or eat it until it’s right for them. The taste of natto is actually not that bad. It’s the unpleasant smell and stringy texture that may be startling and unfamiliar to most Western taste buds and palates. However, if you can tolerate it, it’s packed with powerful nutrients that can have a big impact on your overall health.

Health Benefits

1. Rich in Vitamin K

One of the main reasons natto is so healthy is that it’s high in vitamin K. In fact, the Department of Public Health reports that it contains 100 times more vitamin K2 than cheese!

Vitamin K2 is important because it is considered a key component in maintaining bone mineral density in postmenopausal women with osteoporosis. This is good news for vegetarians and vegans, as natto is one of the few plant sources of vitamin K2.

A higher intake of vitamin K2 is associated with a lower risk of heart disease, calcification of the arteries and death. Vitamin K2 also supports bone health by increasing bone mass and slowing the bone loss that occurs over time.

2. Contains Nattokinase

During the fermentation process, soy is easier to digest and absorb, which is good news for those who usually suffer from intestinal issues when eating legumes. One of the reasons natto doesn’t trigger gastrointestinal discomfort like other forms of soy is the enzyme nattokinase. Created during the fermentation process, nattokinase is used for a variety of medicinal purposes, including to treat:

heart disease
high blood pressure
chest pain
Deep vein thrombosis
Varicose veins
Bad circulation
Peripheral arterial disease
Chronic fatigue syndrome
Muscle spasms
Uterine fibroids

3. Rich in probiotics

Another key to the health benefits of natto is its richness in probiotics. Bacillus subtilis (also called Bacillus uniflagellatus, Bacillus globigii and Bacillus natto) is the bacteria added to soybeans which are then allowed to ferment to create natto. It helps synthesize enzymes, which serve to reduce blood clotting, and produces vitamin K and B vitamins. At one point in its history, it was even used as a broad-spectrum antibiotic. Research shows that supplementing with Bacillus subtilis improves symptoms of irritable bowel syndrome, promotes a healthy microbiome, and helps protect against inflammation. In general, however, the main benefit of fermented foods like natto is that they support overall health and immunity to reduce your risk of disease and keep your body in top shape.

4. Promotes Bone Health

Natto is loaded with several important micronutrients that play a major role in bone health. Calcium, for example, is one of the main structural components of bone tissue and is absolutely essential for preventing bone loss throughout life. Vitamin K is also crucial for bone health, with studies showing that a deficiency in this key vitamin can increase the risk of bone abnormalities like osteoporosis and fractures. Manganese, zinc, and copper are just a few other minerals that are abundant in natto and important for maintaining bone density.

5. Improves Digestive Health

Eating probiotic foods like natto can help balance the bacteria in your gut and optimize the health of your digestive system. Research shows that disruptions to this delicate gut microbiome can have serious consequences, ranging from digestive issues to increased allergy severity, and more. Abundant consumption of probiotics from diet or supplements has been shown to be beneficial in the treatment of diarrhea, ulcerative colitis, and irritable bowel syndrome, among others.

6. Keep your heart healthy

Topping the list of the most nutrient-dense foods on the planet, it’s no surprise that including a serving or two of natto in your diet can have a big impact on your heart health. With over nine grams of fiber per cup, natto can help lower cholesterol levels and prevent plaque buildup in the arteries. It is also rich in vitamin K2, which has been linked to a reduced risk of arterial calcification and coronary heart disease. Plus, studies even show that consuming nattokinase, the main enzyme found in natto, has been linked to lower blood pressure and decreased blood clotting. By controlling your blood pressure, you can ease your arteries and keep your heart muscle healthy and strong.

Nutrition Facts

While natto’s appearance doesn’t leave a very good first impression, its nutritional profile is worth giving it a shot. It is an excellent source of protein, fiber, vitamins and minerals. Additionally, the Bacillus subtilis in natto creates an enzyme called nattokinase, which promotes vitamin K2 production and helps maintain heart health.

Rich in macronutrients and micronutrients, natto is fantastically nutritious, which is why people who eat it regularly experience a wide range of health benefits. It’s the very definition of a “superfood” and each serving contains huge amounts of beneficial nutrients.

One cup (about 175 grams) of natto contains approximately:

371 calories
25.1 grams of carbohydrates
31 grams of protein
19.3 grams of fat
9.4 grams of dietary fiber
2.7 milligrams manganese (134% DV)
15.1 milligrams of iron (84% of the daily value)
1.2 milligrams of copper (58% of the Daily Value)
40.4 micrograms of vitamin K (51% of the daily value)
201 milligrams of magnesium (50% DV)
380 milligrams of calcium (38% DV)
22.8 milligrams of vitamin C (38 percent DV)
1,276 milligrams of potassium (36% of daily intake)
5.3 milligrams of zinc (35 percent DV)
15.4 micrograms of selenium (22% DV)
0.3 milligrams of riboflavin (20% of daily intake)
0.3 milligrams of thiamin (19 percent DV)
0.2 milligrams of vitamin B6 (11% of the daily value).
In addition to the nutrients listed above, natto also contains a small amount of folate, pantothenic acid, and sodium.

Soy products

Although natto can be made with black beans, adzuki beans, kidney beans, and even sunflower seeds, the bacteria used to make it grow best on soybeans, which help produce nattokinase more efficiently. It is important to note that nattokinase is not found in other unfermented soy foods, which makes the distinction between natto and unfermented, genetically modified soy very clear.

* criptom strives to transmit health knowledge in a language accessible to all. In NO CASE, the information given can not replace the opinion of a health professional.