Bacteria in the guts of some Japanese people may have acquired the ability to digest seaweed because of the sushi their human hosts consume, researchers have reported. The evolved trait enables their human hosts to digest carbohydrates found in edible seaweed such as nori, whose tough cell walls the human body cannot process on its own.
The finding, published Thursday in the journal Nature, was stumbled upon by biochemists at the National Center for Scientific Research and Pierre and Marie Curie University in France while seeking enzymes that could digest carbohydrates in the walls of certain red algae, The Los Angeles Times reported.
According to NPR, the bacterium, Bacteroides plebeius, lives in the human gut, along with trillions of other microbes. And like many gut bacteria it has acquired genetic sequences that allow it to produce lots of different digestive enzymes.
But B. plebeius apparently did not have an enzyme capable of digesting seaweed 40,000 years ago, when people first began to arrive in the Japanese archipelago, says Jan-Hendrik Hehemann, the paper's lead author and a researcher at the University of Victoria in British Columbia, Canada.
There was no need, because it appears "their continental ancestors ate only higher plants," Hehemann says.