An enzyme in Japanese food natto beans could help to prevent Covid-19 infection, according to research conducted by Tokyo University of Agriculture and Technology (TUAT).

The fermented soya beans, which have been a popular foodstuff in Japan for over 1,000 years, contain extracts which researchers believe break down spike proteins on the surface of coronavirus, in turn preventing it from infecting other cells. 

This is a fairly significant discovery because people become infected with Covid when the spike proteins on the virus' surface become attached to receptors on the human cell. 

If natto beans break down the spike proteins, it could prevent the virus from attaching to the human cell and therefore prevent infection. 

It is not yet certain as to what the exact molecular mechanism responsible for destroying the spike protein is, but it is thought more than one enzyme may be involved. 

Scientists combined the extract with the Covid virus in test tubes and discovered it prevented infection of cultured cells. 

However, since the experiment used extract, it is currently unclear as to whether simply eating the natto beans would produce the same results. 

What are natto beans?

Natto is a traditional Japanese dish made of fermented soya beans, known for its slimy, sticky and stringy texture. 

The flavour is often described as nutty, with the beans typically served with rice and soy sauce. 

A recognised health food, natto is lauded for its highly nutritious qualities, with the fermentation developing high levels of probiotics which can improve digestion. 

Other suggested health benefits include strengthening the immune system and promoting a healthier heart. 

Indeed, Japan has the longest life expectancy in the world, with low occurrence of strokes and heart disease. 

What have scientists said about the experiment?

Although early experiments suggest natto beans could play a role in treating Covid, further research is required to understand how this could work in humans. 

Speaking to Japanes newspaper Mainichi Shimbun, author of the study Tetsuya Mizutani said: "Further verification is needed to determine whether it could be a method to prevent an increase in the number of infected people if there are antiviral properties in the food product."