top of page

Immigrant Microbiome Project

Results from a research study on the human gut microbiome and obesity in Hmong and Karen women in the U.S.

The human microbiome

The microbiome is defined as the community of all microbes (bacteria, viruses, parasites, fungi) that live in and on the human body. Our study focuses on the gut microbiome, which are the microbes resident in the human gastrointestinal tract. 


The gut microbiome is essential for: 

  • immune system development

  • metabolism (e.g. break down of dietary fibers)

  • protection against pathogens

  • and many other functions


We know that people who move to the U.S. are more likely to gain weight than if they were to stay in their native country. We wondered if perhaps the gut microbiome had a role.

Your immune system and microbiome form a special relationship immediately after birth, and develop together.

External factors (diet, antibiotics, the environment, etc.) are important in shaping your gut microbiome.

Every person has a unique gut microbiome, but people from different parts of the world have very different gut microbiomes.

obese person.png
lean person.png

A diverse gut microbiome is a healthy gut microbiome. Obese people have lower gut diversity than lean people.

Our Research Study

The Immigrant Microbiome Project was an academic-community partnership

built upon equity, inclusiveness, and shared values.

This research project collaboration included the University of Minnesota, the Somali, Latino, and Hmong Partnership for Health and Wellness at West Side Community Health Services in Minnesota, and Chiang Mai University and the Shoklo Malaria Research Unit in Thailand.


We conducted the research with 519 Hmong and Karen individuals living in Thailand and the United States, including first- and second-generation immigrants and 19 Karen individuals sampled longitudinally, and 36 US-born European American individuals.

For every participant, we:

  • Collected stool sample(s), dietary intake information, migration history, and demographic data

  • Measured waist circumference, weight, height

  • Collected information on breastfeeding as a child, tobacco or alcohol usage, and medications

  • Excluded them from participation if they consumed antibiotics within the last 6 months, were regular users of probiotics, were pregnant, or were immunosuppressed


Community was central to our project, from its inception to the end.


Community Advisory Boards

Members of the Hmong and Karen communities served on our boards as voices for their communities. They consulted on our study design, troubleshooted recruitment challenges, and helped us find ways to interpret our scientific findings into meaningful results.


Community Researchers

Our Hmong and Karen community researchers were members of our research team from Day 1. As trusted leaders in their communities, our researchers were critical for the successful recruitment of all of our study participants. Learn more about our team here.


Community Dissemination

We published our results, and also created a pamphlet and shareable English, Hmong, and Karen videos. In 2017, we offered workshops centered on Hmong food traditions maintain health, and partnered with UMN Extension to host nutrition and cooking classes in Karen.


  • We found that Hmong and Karen in Thailand were leaner and also had the highest gut biodiversity, compared to those in the U.S.

  • Hmong and Karen gut microbiome changes within months of arriving in the U.S. and continue becoming more "Americanized" for decades

  • Changes in diet explains some, but not all, changes in the gut microbiomes


Gut biodiversity decreases with time in the U.S. and increasing Body Mass Index (BMI)


Hmong immigrants have gut microbiomes that can no longer degrade certain fibers that they used to


Second-generation Hmong American gut microbiomes look fully Americanized, but they still eat Hmong foods


Non-Western gut microbiomes look more Western in composition after about a decade in the U.S.


Consumption of sugars, fats, and proteins increases with longer residency in the U.S.

Diet & Microbes

Diet is important but does not explain all of the variation in Hmong and Karen gut microbiomes

There are many complex factors that contribute to obesity, and we still have many important questions to answer. We know that Hmong and Karen obesity risk increases after moving to the U.S., and now know that their gut microbiomes change as well.

Our results underscore the importance of preserving traditions not only for Hmong and Karen culture, but also with potential to preserve Hmong and Karen microbiomes and health.

Meet Our Team

Pajau Vangay, PhD

Principal Investigator

Pajau was a Ph.D. student in the Knights lab at the University of Minnesota and led the Immigrant Microbiome Project. While her research interests include the microbiome sciences, reducing health disparities, and food/nutrition, she is passionate about the democratization of science. She is currently a Science & Technology Policy Fellow with the California Council on Science and Technology.

Please reload

Dan Knights, PhD

Principal Investigator

​Dan is a professor in the Department of Computer Science and Engineering and the Biotechnology Institute at the University of Minnesota. Dan received his PhD from the University of Colorado, followed by a post-doctoral fellowship at Harvard. His research uses data mining and machine learning to aggregate and mine multiple sources of microbial and human genomic data for patterns linking to environmental conditions and human disease. 

Rodolfo Batres, MD

Project Coordinator

Rodolfo is a medical doctor from El Salvador who has worked as a researcher with SoLaHmo since 2014.  He is participating in various community-based participatory action research projects. His research interests are broad, but have the common goal of improving the health and wellness of Minnesotans, particularly within the Latino community.

Bwei Paw

Community Researcher

Bwei Paw has had previous experience as a nurse, health worker, and medical educator in Thailand where he worked with Burmese migrants. Bwei currently is a staff member at Neighborhood House, where he helps new Karen refugee families get settled in the Twin Cities. He is interested in health and community education, particularly with the Karen.



Nancy Yang

MD Candidate, Research Student

Nancy is a medical student at the University of Minnesota who assisted with dissemination and community engagement of the Immigrant Microbiome Project. She is interested in using research to engage marginalized communities and elevate health practices beyond Western medicine.

Please reload

Kathleen Culhane-Pera, MD, MA

Principal Investigator

Kathie is a family physician and medical anthropologist who has worked with Hmong and inner city residents of St Paul, Minnesota since 1983 and with SoLaHmo on community-based participatory action research projects since it’s inception in 2009. She is co-editor of Healing by Heart: Clinical and Ethical Case Stories of Hmong Families and Western Clinicians.

Shannon Pergament, MSW, MPH

CBPAR Specialist

Shannon is Co-Director of Community Based Research at West Side Community Health Services, Inc. (West Side) and is a founding member of the Somali, Latino and Hmong Partnership for Health and Wellness (SoLaHmo), a community driven translational research program of West Side.


Mary Xiong

Community Researcher

Mary is a Hmong community organizer who is passionate about health equity. She enjoys working and providing community health education and outreach to all communities. She has led the Hmong MN Pageant Committee as Chair since 2014, Vice-Chair for the Hmong Health Care Professional Coalition 2015-2016. Currently, she is the Program Manager for Planned Parenthood MN ND SD's EHDI programs working with Hmong youth and parents in Minnesota.

Pimpanitta Saenyakul, PhD, MPH

Community Researcher

Pimpanitta is a Hmong researcher who specializes in Nursing, and served as a community researcher for the Immigrant Microbiome Project in Minnesota in 2016. She is currently is a Senior Technical Officer in HIV Treatment and Adherence at Family Health International based in Thailand. She completed her PhD in Nursing, MPH, and BS in Nursing from Kent State University.

Please reload

Meet our team

This research was funded by grants from the UMN Clinical and Translational Science Institute, UMN Institute on Diversity, Equity and Advocacy, UMN Healthy Foods Healthy Lives Institute, and the UMN Graduate School. Outreach activities were funded by Allina Health.

Images were designed by Annie Au and Jennifer Moss.

Icons used throughout this website were designed by Freepik.

bottom of page