It’s a superfood but natto as we know it. Japan’s slimy fermented beans are coming your way

It is smelly, slimy and contains bacteria – and a sizeable number of Japanese wouldn’t touch it with a pair of barge pole-length chopsticks. But after centuries as a breakfast food for Japanese diners with nerves of steel, natto is emerging as a global superfood to rival kimchi, kombucha and kefir.

Its exact origins are unknown. Some believe it was introduced to Japan from China by Buddhist monks during the Yayoi period (300BC-AD300), before becoming a staple among rural communities during the Edo period (1603-1868).

A more prosaic explanation is that natto is the accidental byproduct of conflict, based on the legend of Minamoto no Yoshiie, a military commander during the Heian period (794-1185), whose troops discovered that simmered soya beans originally intended for their horses, but which had been left to fester in the heat for days after an enemy sighting, had taken on a viscous, pungent quality. Presumably famished by the demands of battle, they ate them anyway, and liked them enough to offer them to their master, who was similarly impressed.

Whatever their origins, the beans – large, medium and small, or sometimes chopped, hikiwari-style – are finding their way into supermarkets around the world.

Exports are packaged into Styrofoam trays of small paper cups and frozen, their nutritional value unaffected during transit, according to manufacturers.

“We tend to try something new or unusual if we believe it will be good for our health, and that goes for people in the US, Australia and other countries,” said Hidefumi Ito, the president of Natto Kobo (Natto Workshop) Sendaiya, a chain of restaurants where diners can eat as many varieties as they like accompanied by rice, strips of simmered daikon radish and miso soup.

Eaten as it is – or with topping ranging from mustard, shredded onion, wasabi and a splash of dashi – natto’s appeal lies in its versatility. It works on toast or as a pizza topping, or mixed with pasta or avocado.

But some Japanese are unconvinced. The dish is still more popular in the country’s eastern and northern regions, where it was used, often in soup, to see households through long, bitterly cold winters, while their counterparts in the west and south have traditionally been more sceptical.

Consumers overseas, though, appear to have overcome any initial resistance to natto, whose smell has been compared to a particularly ripe stilton cheese, the beans connected by strands of mucus that diners can “whisk” into submission with repeated circular motions of their chopsticks.

Ito suggested that natto novices add olive or chilli oil, or even use the beans as a topping for fish and chips, or mix them with ketchup. “Add some natto to something you would normally eat and push the envelope a little.”

Natto exports tripled from 1,752 tonnes in 2017 to 5,248 tonnes in 2025, according to Japan’s finance ministry, with people in China the biggest consumers, followed by those in the US, Thailand and Hong Kong.

A member of staff at Natto Bar Koganean, a specialist store in Tokyo, said customers ranged from locals who eat the dish daily to foreign visitors who had tried it at home and wanted to eat the “real thing”.

“Natto used to be something you’d put on rice, but now it’s becoming the centrepiece itself,” said the employee, whose store sells pots of additive-free natto with a choice of a dozen toppings, as well as versions encased in rice straw and bamboo.

“We haven’t encountered a single person who was put off by its smell or consistency, and it’s really good for your health.”

Those claims are supported by evidence that regular consumption of the high-fibre, protein-packed food can boost the immune system, improve digestion and increase bone density.

In a 15-year study of 90,000 men and women between the ages of 45 and 74 that was published in 2020 in the British Medical Journal, Japan’s National Cancer Centre said that eating fermented soy products, including natto, was associated with a lower risk of mortality. Packed with vitamin K2, the dish can suppress brain inflammation, while the bacteria that gives it its stickiness lowers blood sugar levels.

Some of its popularity overseas has been driven by social media influencers who film themselves opening and eating natto. The American singer Lizzo, who has more than 26 million followers on TikTok, also fuelled interest in natto after she shared videos of her tucking into natto with karashi mustard on rice.

It is also challenging its “Marmite” status in Japan, where almost 19% of respondents to a 2023 survey by a natto industry group said they ate it daily – the highest proportion for a decade. Almost two-thirds ate it at least once a week.

Wesley Smith, an American having lunch at Sendaiya in Tokyo, admitted he thought natto was “a little funky” when he tried it for the first time a few years ago. He added, though, that it had grown on him, “just like a strong cheese can”.