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

A lot changed for Minnesota-based chef Yia Vang's family when they fled persecution in Laos and resettled in the American Midwest in 1988. For one, "I think my parents realized they do not want 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've changed and they've changed.

Moving to the U.S. can seriously mess with immigrants' microbiomes, according to a new study that is tracking the digestive health of Minnesota from Southeast Asia. "We found that when they came to the U.S.A.," they said, "has a quantitative biologist at the University of Minnesota and the study's senior author. Asian staples like wild greens, coconut, and tamarind.

The study, published in the journal Cell On American microbiome, "says Knights – one that tends to be less diverse, featuring fewer strains of bacteria. "And while we do not know whether this is obesity, we know it is at least associated with more obesity," he says.

Knights and his colleagues arrived at these hypotheses by analyzing the intestinal bacteria in the United States, including first and second-generation immigrants. (The researchers focused on women in the United States.) The scientists then compared the immigrants' microbiomes to those of Caucasian Americans. The researchers also followed a group of 19 Karen refugees as they relocated from Thailand to America, tracking their changing microbiology during the transition.

Among the group of 19 refugees, researchers noticed that Bacteroides began to displace the non-Western strain Prevotella Within their first six months in the United States they have lost their microbes that they have gained – "so the diversity in their microbial communities decreased," Knights says. "And some of the Prevotella they have been helped by digest fiber from plants and greens. "

Among the immigrants, it became clear that they spent more in the US, the more their microbiomes diverged from those of ethnically similar living people in Thailand. Second-generation Hmong- and Karen-Americans-born in the United States to parents who have moved from abroad -had more microbiomes than they were.

By tracking everyone 's food logs, the researchers found that an Americanized diet – featuring less fiber, and more processed sugars – played a role in disrupting immigrants' microbiomes. Some of the bacteria in our guts feed, and survive, and we do not get enough.

But changes in diet did not explain all – or even more – of the change in immigrants' microbiomes. "It could be that other factors, like exposure to different medications, especially antibiotics or changes in the quality of water they're drinking, are also affecting their microbiomes," says Pajau Vangay, a researcher at the University of Minnesota who co-authored the study. In any case, Vangay notes, researchers are still untangling the influence of diet and microbiome on obesity. Doing so could help explain why immigrants are particularly vulnerable to rapid, unhealthy weight gain.

"In speaking with community members, we also realized that for them, the biggest concern was obesity," says Vangay. "Because they have watched in their relatives and friends when they moved to the U.S., they did not really change their diet."

This new study is a good first step in solving that mystery, says Dr. Gloria Dominguez-Bello, a microbiologist at Rutgers University who was not involved in the research. "I strongly believe in this issue, more in the world of immigrant groups and people all over the world," she says. "Because one thing is clear: Human populations are migrating, and they are prevalent in Westernizing."

Further research could also reveal what immigrants – and all Americans – who are struggling with obesity can do to improve their health. In the future, researchers may be able to develop probiotics that they could not compensate for microbes they've lost, Dominguez-Bello suggests.

"For now, our study can not provide any obvious solutions for obesity," Vangay says. But rather than leaving the community members hanging, she's working with community leaders and local health care providers to educate the people about the value of traditional cooking.

Last year, she worked with chef Vang – who in his adulthood has gotten off the frozen chicken tenders and embraced traditional Hmong cuisine at his pop-up restaurant Union Kitchen – to teach a series of nutrition and Hmong cooking classes.

"Growing up, like when I was in high school, and we would like to 'Mom, we really want spaghetti, we really want that that American food,'" Vang says. "Now it's Hmong food like steamed fish or braised vegetables – that's the stuff that revives my soul; it's my comfort food."

But unlike a lot of American comfort foods, he says, "I know it's good for me, I do not feel heavy when I'm done."