Let’s boost up our immune system with Japanese traditional plant-based superfood, Natto

Since last year, Japanese traditional fermented food, Natto, has been in the spotlight all over the world. This food has a unique consistency and a strong fermentation odor that has been dodged by non-Japanese people over the years.

Meanwhile, the era of Covid19 has arrived and Natto started attracting people’s attention. But why?

This article will show what makes Natto nutritious and why you should consider trying it.

Why is Natto attracting people now?

Last June, Dutch scientists published a finding that Vitamin K was one of the keys to preventing aggravation of Covid 19 symptoms. There are two types of Vitamin K, K1, and K2 which has a higher absorption efficiency into our body when taken orally. The scientists also mentioned that “Natto is quite rich in Vitamin K2.” (240μg of Vitamin K2 per pack of Natto. Recommended daily intake = 65-80μg) When this scientific result was revealed in February, Natto attracted people's attention, especially in Europe.

Secondly, it was found that one type of amino acid 5-ALA, which can suppress the growth of viruses, is abundant in Natto, red wine, and other fermented foods.

With the growing popularity, Natto is now available to buy at almost every grocery store in Malaysia.

In addition to those benefits above, Natto still has many other distinguished potencies. Let’s talk about the true power of Natto!

What is Natto?

Natto has been loved and eaten by the Japanese from ancient times, as far back as the Jomon period (14,000 – 300 BCE). There are various opinions on how the present style of Natto was formed. The famous one is as follows. “One day in the Heian period, a thousand year ago, when soybeans were boiled as military food by soldiers, they were attacked by the enemy. They wrapped the boiled beans in straw and tied them to the saddle of the horse. After the battle, soldiers found a unique smell from the straw and opened it. Hereupon the beans were threaded, but they realised that they could still eat and the taste was even great”.

In fact, Natto is a traditional Japanese dish consisting of fermented soybeans and characterized by low calories, less fat, a stringy texture, and distinctive flavor. Traditionally as one theory above, Natto is made by wrapping boiled soybeans in rice straw, which naturally contains the bacteria Bacillus subtilis on its surface. Bacteria ferment the sugar present in the soybeans producing Natto.

Currently, Bacillus subtilis bacteria is directly put on the boiled soybeans for the fermentation process, then styrene foam is used instead of straw.

Are soybeans hard to digest?

Soybeans naturally contain antinutrients, which can make it difficult for our body to digest them. Antinutrients are also said to reduce the nutrients our bodies absorb from foods and cause some people troubles.

Interestingly, the fermentation process to make Natto helps reduce the levels of antinutrients and facilitate digestion.

Why is Natto considered a Superfood in Japan, well-known for longevity?

It was just 70 years ago that the culture of eating meat began among Japanese people. Before that, we took protein from several kinds of beans or plant-based products like Natto for health reasons.

Natto contains fantastic levels of many nutrients that are important for optimal health, such as Probiotics, Protein, Iron, Fiber, Magnesium, Vitamin C, Vitamin K1 and K2, Selenium, Mineral, Zinc, and small amounts of Vitamin B6. The level of nutrients is enough to contribute to stronger bones, facilitate digestion, help reduce cholesterol levels, and help strengthen your immune system.

Furthermore, the secret weapon hidden in Natto is called Nattokinase, a type of enzyme produced during the fermentation process. This helps dissolve blood clots and lower blood pressure, contributing to a healthier heart. This super nutrient seems to be especially concentrated in the “stringy portion” of Natto.

Eating Natto regularly may provide you several other benefits (may help you lose weight, improve brain health, etc.), however, they are still required to prove under further research.

Types of Natto

You may see a variety of packages of Natto in the freezer at a grocery store, as there are many brands. However, taste and texture have no obvious difference. Natto is broadly separated into two types. Chopped type or a non-ground one. The chopped type is called “Hikiwari or Kizami”, and the non-ground type is called “Tsubu-natto”. Which one is better? It just depends on your taste. From the point of view of digestion, Hikiwari and Kizami are easy to digest, so it would be good for children and elderly people.

Hikiwari or Kizami Natto (crashed or chopped type)
Tsubu Natto (non ground type)

How to eat Natto?

In Japan, Natto is typically topped with soy sauce, diced spring onions, and other seasonings then served with cooked rice. The mustard, generally packed together in a container, works well to reduce the smell if you are worried about it. But please note that Nattokinase is easily spoiled by heat, therefore, you can just enjoy simply without cooking.

- Simple step to eat –

1. If Natto is frozen, thaw first at room temperature (around 20-30 minutes).

2. Open a container, and remove a plastic sheet.

Stir up well until threads appear, before adding sauce
Natto containing miracle nutrient, Nattokinase

3. Stir well with chopsticks or fork, until being stringy (Nattokinase is in this stringy portion).

4. Add (sauce called “tare”) soy sauce (including dashi; fish stock) and mustard contained in the box, and stir well again.

5. Done and let’s serve!

- Arrangement example –

- Ex.1 Mix boiled and chopped lady’s fingers with Natto

- Ex.2 Serve on the Soba noodle or Udon

- Ex.3 Mix with Kimuchi

- Ex.4 Mix with Tuna

● If you have a Yogurt Maker, homemade Natto is also available easily. Please follow the instructions of each machine.

Natto with Ooba and green onion
This is Ooba (green shiso, Japanese basil)

Natto is a super nutritious food that is worth taking. If you are planning to have it for the first time, just start with a small portion topped with condiments (mustard, spring onion, or chives, boiled lady’s fingers etc.)


Natto is generally safe for most people. Even so, the persons who are already taking blood-thinning medication should ask the doctor before taking Natto, because Natto contains Vitamin K1 which has a blood-thinning component.

Besides, soybeans are considered a Goitrogen which may interfere with the normal functioning of the thyroid gland for individuals with thyroid problems (This is unlikely to cause a problem for people with no thyroid problem). For those with impaired thyroid function, please consult your doctor before you eat).