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Tag: immigration

Cellular Roadblocks for Immigrants: The Loss of Gut Microbe Diversity

Recent evidence from the University of Minnesota in conjunction with the Somali, Latino, and Hmong Partnership for Health and Wellness suggested that immigrants and refugees moving to the United States were likely to experience a rapid change in their gut microbes. Described as “westernizing” to their environment, immigrants tended to lose their diverse, native microbes in favor of microbes that are common to European Americans.

The participants of this study originated from Southeast Asia, specifically the ethnic minorities of Hmong and Karen from China, Burma, and Thailand. The study used ethnic minority communities from both Southeast Asia as well as those living in Minnesota as a comparison, analyzing the gut microbes in these participants and using Caucasian American people as controls. The researchers also looked into the first generation children of these immigrants. Additionally, the study was able to follow a group of nineteen Karen refugees, tracking the changes in their gut microbes as they traveled to the United States.

The study discovered that the gut microbes in these participants changed rapidly. Particularly, in the group of Karen refugees, the Western strain of Bacteriodes replaced the non-Western strain of Prevotella in the matter of less than a year. Furthermore, the overall gut microbe diversity continued to decrease in all participants in the United States in relation to the length of their stay. Likewise, the children of immigrants had a more profound decrease in diversity. Researchers in this study suggested that this decrease in microbe diversity may have been a result of a Western diet, or for the children, growing up in the United States.

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Closeup of Bacteroides biacutis(Image Credit: CDC/Dr. V.R. Dowell)


So why does this matter? Well, the study established a correlation: the greater the “westernization” of gut microbes, the greater obesity in immigrants. This obesity problem appeared to be more prevalent in immigrants, and the study had discovered a key piece of evidence for why.

“When you move to a new country, you pick up a new microbiome.” Dan Knights, one of the key authors of the study as well as a quantitative biologist at the University of Minnesota, says. “…What enzymes they carry…may affect the kinds of food you can digest and how your diet affects your health. This may not be a bad thing, but we do see that Westernization of the microbiome is associated with obesity in immigrants.”


Welcome to America, here is a risk of obesity?

Each individual has a personalized micro-biome with trillions of bacteria weighing about half a pound. We receive this microbiome at birth as a departing gift from our mothers, but this microbiome does not remain the same through the years. Studies by Dan Knights from the University of Minnesota have shown, however, that geographic location and diet results in shifts in our gut microbiota.

         Figure 1


So what does this mean?

The study by Dan Knight shows that immigration is causing dramatic shifts in new arrivals to the country. These new arrivals surveyed through stool samples are from places in Southeast Asia including 500 women of Hmong and Karen descent. These 500 women varied from individuals remaining in Thailand where most Hmong and Karen people live currently, first- and second-generation U.S. immigrants, and even included 19 Karen women followed through their first six to nine months in their new nation. All of these samples were then compared to 36 European Americans born in the United States.

On the microscopic level, the aforementioned immigrants are facing a shift in the gut microbiota from Prevotella bacteria to Bacteroides. “Prevotella bacteria produce enzymes that digest fibrous foods more common in Asia than the United States. In Thailand, the women ate more palm, coconut, a fruit called tamarind and the bulbous part of a plant named konjac.” This shift in bacteria causes a loss of 15% of microbiome diversity and furthermore does not shows signs of compensating for the loss of native microbes.

As the diversity shifts towards that of European American, obesity rates seem to spike among the population. The immigrants’ obesity rates increased by nearly six times, which is a drastic shift for the immigrants who held an originally low risk of metabolic disease. This shift, however, is still a complete mystery. The researchers cannot pinpoint the true cause as diet, location, medicines, water composition, or an unknown but there is a clear correlation between obesity and the lessened diversity in the gut microbiota. This correlation was discovered through an experiment involving mice injected with germs from obese women. These mice subsequently became heavier despite having the same food as their lean equivalents. Knight and his colleges plan to continue their studies in hope to possibly provide a solution to obesity through the injection of Prevotella, as they are driven by the intense sensitivity and stake of their subjects’ health.

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Figure 2: Experiment on Obesity with Mice



While immigration to the United States, a place of opportunity, may appear a blessing it does not come without risks. As the leading nation in obesity, it comes as no surprise that something is causing a drastic shifting in newly immigrated individuals’ gut microbiota and larger micro-biomes resulting in a higher risk of obesity. A gift and a curse, however, this phenomena has resulted in research that could possibly grant new insight on how to prevent obesity.



Food For Thought!


A small fence separates densely populated Tijuana, Mexico, right, from the United States in the Border Patrol’s San Diego Sector. Construction is underway to extend a secondary fence over the top of this hill and eventually to the Pacific Ocean.









Here is some food for thought, what defines American Culture? Democracy? Freedom? As a matter of fact, for many immigrants, food is a defining factor of moving to the United States of America. Immigrants are fascinated by the combination of a wide variety and convenience of food. By the same token, the typical “American” diet is loaded with saturated fats, complex sugars and harmful chemicals. According to a recent Study from National Public Radio (N.P.R.), when immigrating to the United States of America, the typical “American” diet causes a completely new gut microbiome. The gut microbiome is the natural bacteria found in the digestive system that assist the body in a wide variety of tasks.

In order for N.P.R. to test this hypothesis, they gathered 500 ethnically Hmong & Karen women, residing in either Thailand or the United States of America. Of these women, they were either a first or second generation immigrant. After recording their findings, N.P.R. moved back to the United States of America, solely. When observing the gut microbiomes of the of caucasian Americans, the researchers concluded that the presence of Bacteroides leads to the decreased function of the gut microbiome. Next, 19 of the 500 women from Thailand moved to the United States of America. After many observation hours and careful logging of food consumed, the gut microbiomes of the immigrants began to diverge from their natural affinity. When reviewing the food logbooks, the scientists/researchers concluded/discovered that the typical “American” diet leads to the disruption of the gut microbiome because of its lack of fiber and over use of sugars.

Although this is not an urgent issue, this is an issue that must be addressed in the near future; this article exploits a greater issue for the United States of America. The United States of America is in desperate need to change its diet, consisting rich in fats and sugars, the population is facing serious medical issues such as obesity, cancer, high blood pressure and more.  This article demonstrates the effects of the typical “American” diet has on the United States of America. The United States of America must work quickly to collaborate with citizens and the private sector in order to make healthy alternatives to food, cheaper and more convenient, in order to mitigate health issues as well as promote preventive medicine.

Thank you!

From your favorite bacteria,





Does Immigration Alter the Microbiome?

Each human has our own microbiome; one that is unique to us. However, recent research has shown that the microbiome of someone’s body is not static, but highly subject to alteration. Microbiomes change depending on the atmosphere you are in- and they change very quickly, taking only nine months in the U.S. The University of Minnesota has found that, in people emigrating to the US, microbiomes “rapidly westernize”; aka, their native microbes are replaced with new ones. However, this shift in microbes is not equal- there aren’t enough new microbes to replace the old, resulting in a harsh decline in diversity; diversity that stimulates metabolism, digestion, and immune system development.

Dan Knights, a computational microbiologist at the University of Minnesota, states that in moving to another country, you pick up new microbes native to that country, and new disease risks as well. In this case, the shift in the microbiome makeup can be beneficial, as the new microbes may aid in defense against new disease. However, it has also been found that “Obesity rates among many of the study immigrants increased sixfold. Those who became obese also lost an additional 10 percent of their diversity.” This fact links diet shifts to microbiome shifts, yet Knights states that “diet alone wasn’t enough to explain the rapid Westernization of the microbiome,” and that other things such as water and antibiotic use factor in as well. However, diet is still an important part in microbiome health and diversity. Knights studied microbiota of Hmong and Karen women who had immigrated to the U.S., these immigrants’ American-born children, and white American controls. Their microbiomes shifted to Prevotella to Bacteroides, coming to resemble those of the white Americans who acted as the control. The immigrants’ children were even more susceptible to changes in and loss of microbial diversity.

Obesity statistics worldwide from the years 1996-2003.

We as Americans are highly aware of our obesity epidemic and are doing all we can to find a way to fix it. Research that links it to a cause relieves people- it provides hope that there is a way to change it. Knights remarks that “we do see that Westernization of the microbiome is associated with obesity in immigrants, so this could an interesting avenue for future research into treatment of obesity, both in immigrants and potentially in the broader population.” However, it cannot be used as an excuse for our problem as Americans- it is simply a breakthrough in a long journey that may help us in the long run.

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