April 8, 2010
by Sam Savage
Researchers have discovered that a marine germ typically found on the seaweed used to wrap sushi interacts with internal bacteria in our bodies and helps with the digestive process.
According to a group of scientists from the National Centre for Scientific Research (CNRS) in Roscoff, France, an enzyme known as porphyranase helps break down carbohydrates in the cell walls of Porphyra, a red algae that is the main ingredient of the nori sheets used to wrap sushi.
The enzyme was also discovered in microbes that were extracted from the intestines of Japanese subjects, but was notably absent from intestinal bacteria of North Americans.
Through a genetic transfer, these substances help us break down starchy fibers, while keeping some of the nutritional content from the digested sushi for themselves.
According to what lead author Mirjam Czjzek told Jessica Hamzelou of NewScientist, the CNRS study provides “the first evidence that food bacteria can transfer genes to our own gut bacteria, and could help us extract more energy from food.”
“This gives us a hint at how the diversity of bacteria we have in our guts arises and evolves,” Czjzek told science correspondent Ian Sample of The Guardian. “What we eat and how we prepare it can have an influence on our microflora.”
The research was published in the online journal Nature.
In an article accompanying the CNRS paper, Stanford University assistant professor of microbiology and immunology Justin Sonnenburg notes, “Without the trillions of microbes that inhabit our gut, we can’t fully benefit from the components of our diet. But cultural differences in diet may, in part, dictate what food our gut microbiota can digest.”
“The next time you take a bite of an unfamiliar food, think about the microbial inhabitants you may also be ingesting, and the possibility that you will be providing one of your 10 trillion closest friends with a new set of utensils,” he adds.
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