What is Natto and is it Good for You?

Natto is a traditional food in Japan made of fermented soybeans which texture is sticky, stringy, and slimy. It’s somewhat pungent smell make it easy to recognize, while, it has a pronounced nutty taste.


Natto is a traditional fermented food famous in Japan. Made with fermented soybeans, natto has an odd consistency that is sticky, stringy, and slimy. Natto also has a surprising, somewhat pungent smell that makes it easy to recognize. It has a pronounced nutty flavor, which, according to consumers, is an acquired taste.

The Japanese people serve natto with cooked rice and season it with soy sauce, chives, mustard, etc. While natto has health benefits, some people say it can have negative effects on the body, too.

So, how does natto really affect our health? Is it really good for us?

Brief History

The traditional way of making natto includes boiling soybeans and wrapping it in rice straw. Rice straw naturally contains the bacteria Bacillus subtilis.

Doing the process produces natto by allowing the bacteria to seep and ferment the sugar in the soybeans.

But at the 20th century, as the scientist identified B. subtilis, they isolated it, forcing the maker of natto to modernize its preparation. The fermentation process is begun by adding B. subtilis directly to the beans which containers is now made styrofoam boxes instead of the rice straw.

Health Benefits

he real benefits of natto are hidden under its odd smell and texture. Aside from the small servings of pantothenic acid, folate, and vitamin B6, plus antioxidants and many valuable plant substances, it is full of other vital nutrients. In fact, a hundred-gram portion is crammed with different nutrients:

  1. Fat: 11 grams
  2. Protein: 18 grams
  3. Carbs: 14 grams
  4. Calories: 212 grams
  5. Fiber: 5 grams
  6. Manganese: 76% of recommended dietary intake (RDI)
  7. Calcium: 22% of the RDI
  8. Selenium: 13% of the RDI
  9. Potassium: 21% of the RDI
  10. Vitamin K: 29% of the RDI
  11. Zinc: 20% of the RDI
  12. Magnesium: 29% of the RDI
  13. Vitamin C: 22% of the RDI
  14. Iron: 48% of the RDI
  15. Copper: 33% of the RDI

Because natto undergoes a fermentation process, it produces a condition where probiotic growth is encouraged. Meaning to say, the fermentation process is more healthful than simply boiling the soybeans.

One of the health assistance that probiotics provide is its ability to improve gut health. The consequence of having a healthy gut includes easier food digestion resulting in easier nutrients absorption.

Natto’s Job in the Digestive System

Trillions of microorganisms live in your gut. This is 10 times greater than the cells of your body. So it is necessary to have the right bacteria that can work well with your digestive system.

Natto’s produced probiotics work as a defensive mechanism against harmful bacteria and toxins. In fact, science considers it as your gut first line of defense.

According to researchers, probiotics aids in the reduction of constipation, gas, and diarrhea associated with an antibiotic. It also works against the symptoms of ulcerative colitis, Crohn’s disease, and inflammatory bowel disease (IBD).

Five to 10 billion CFU (colony-forming units) is found per serving of protein-rich supplements and food. On the other hand, a gram of natto consists of one million to one billion CFU. Meaning to say, the same number of probiotics can be served in a gram of natto compared to the whole serving of other food containing probiotics.

Additionally, the fermentation process of soybeans decreases its antinutrients.

All soybeans contain antinutrients which are a substance that makes the beans harder to digest. It can cause nausea and bloating in rare cases because it hinders the body’s capability to absorb many nutrients from food.

Natto’s Contribution to the Bones

Calcium and vitamin K2 are the main mineral and vitamins inside our bones. Both nutrients have important roles in strengthening bones. Vitamin K2, for instance, plays it part by activating bone-building proteins, which assist calcium to get and stay into the bones.

Surprisingly, these nutrients are also present in natto’s nutrient’s package, which make it food to slow down bone fractures. Nevertheless, strong evidence is still needed to know if eating natto alone would produce the same benefits as taking high dosages of vitamin K2 supplements.

How’s the Heart with Natto?

The heart seems happy with natto. It is because natto has the ability to reduce cholesterol through the help of probiotics and fiber. It also possesses an enzyme responsible for dissolving blood clots called nattokinase.

Nattokinase is produced by the fermentation process. In addition in dissolving blood clots, many studies elaborate on its properties in lowering blood pressure by caging angiotensin-converting enzyme (ACE). According to these studies, blood pressure in the participants with 130/90 mmHg and higher is reduced by 3 to 5.5 mmHg.

Vitamin K2 has another calcium-related used. But aside from its assistance to get the calcium inside the bones and stay in it, vitamin K2 also helps the calcium by preventing it to accumulate in the arteries. In other words, it also assists in having a healthy heart.

Natto Can Cause a Stronger Immune System

As natto produce probiotics to stops harmful bacteria from entering, it also improves the production of natural antibodies, which strengthens your immune system.

This results in a reduction of risk infection as well as a fast recovery whenever you get sick.

Furthermore, natto contains the vitamin and minerals C, zinc, copper, iron, and selenium which are responsible for improving immune function and response.

The evidence of the beneficial effects of natto is rather small. Because of this, more research is still needed to conclude its benefits.

How Safe is Natto?

Generally, natto is safe to consume. However, its vitamin K1 content causes blood-thinning. Patients who are under blood-thinning medication should first ask their doctors before including natto in their meal.

Additionally, soybeans are considered goitrogen, and natto’s main ingredient is soybeans. Meaning, it can affect the normal function of the thyroid gland, especially if a patient is already suffering from a thyroid misfunction.

Healthy people might not have problems with goitrogen but individuals with damaged thyroid function should have limited natto consumption.

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