Apparently, only the guts of Japanese people have bacteria that digest the seaweed wrapped so tightly around the oh-so-delicious sushi. And North Americans don't.
Universite Pierre et Marie Curie researchers announced in Nature that they've discovered an enzyme that can breakdown seaweed. And it just so happens that the bacteria that makes this enzyme is also predominantly found the guts of Japanese people.
When the seaweed chomping bacteria called Bacterioides plebeius breaks down the starch, the person benefits by getting more energy. Unfortunately, people who don't have the gut bacteria won't reap the same nutritional benefits from the seaweed.
Evolutionarily speaking, the Japanese did have a head start. They began eating sushi in the 8th century. Today sushi is still a large part of their diet: The average Japanese person eats 14.2g of seaweed a day.
The scientists detected the bacteria when they were testing the genetic makeup of the bugs found on Porophyra seaweed. Surprisingly, the same eleven genes found in the bugs on the seaweed were also detected in the bacteria isolated from the guts of Japanese people. And none were found in the guts of Americans.
The scientists reckon it is possible that the marine genes swapped genetic information with gut bacteria to make it easier for the Japanese to digest the food. That way, the carbohydrate active enzymes, or CAZymes, could breakdown the polysaccharides found in plants. The researchers wrote in Nature:
This indicates that seaweeds with associated marine bacteria may have been the route by which these novel CAZymes were acquired in human gut bacteria, and that contact with non-sterile food may be a general factor in CAZyme diversity in human gut microbes.
Gut bacteria provide essential enzymes to our bodies, to make up for the genetic material the human genome might lack. Good thing our stomachs are stocked with incredibly diverse bacteria. In fact, we have trillions of microbes in our gut that help us digest food — making it clear why we might have a love/hate relationship with exotic dishes.
Image: flickr/ lighto
Updated: I wasn't careful with my use of language, so I made some clarifications. I apologize for the confusion.