Immigrating To The U.S.? Get Ready For A New Gut Microbiome (And Maybe More Pounds)

A McDonald’s billboard in St. Paul, Minnesota advertises in the Hmong language. A new study of first- and second-generation Hmong and Karen immigrants finds their gut microbiomes changed soon after moving to the U.S. Adopting an American diet plays a role but doesn’t explain everything

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A lot changed for Minnesota-based chef Yia Vang’s family when they fled persecution in Laos and, in 1988, resettled in the American Midwest. For one, “I think my parents realized they don’t have to go out and kill one every time we want to eat chicken,” Vang says. “So Tyson chicken tenders were always in the freezer.”

But it’s not just the way they lived and ate that changed — the bacteria that lived alongside and inside them probably changed as well.

Moving to the U.S. can seriously mess with immigrants’ microbiomes, according to a new study that tracked the digestive health of refugees coming to Minnesota from Southeast Asia. “We found that when people come to the U.S.A., they almost immediately begin losing some of their native microbes,” says Dan Knights, a quantitative biologist at the University of Minnesota and the study’s senior author. Some of the strains they lose are ones that help them break down and glean nutrients from fibers found in Southeast Asian staples like wild greens, coconut and tamarind.