Scientific interest in the gut microbiomes of remote populations has
surged in recent years. Biologists study these often-isolated,
hunter-gatherer communities to better understand the dynamic
relationship between diet and the microorganisms that inhabit
Previous studies on rural populations in Burkina Faso,
Tanzania, and Venezuela, for example, have reported finding more
diversity and different microbes in the study populations than what's
found in Western intestines.
‘Dietary fiber is a major factor driving the overall composition of the gut microbiome, suggested a new study.’
Researchers at the University of Montreal, in Canada, have
characterized the gut microbiome of the Canadian Arctic Inuit for the
first time. Reporting this week in mSphere
, an open-access
journal of the American Society for Microbiology, the researchers found
that the Inuit harbor a composition and diversity of gut microbes
remarkably similar to their urbanized, westernized counterparts in urban
Montreal. What differences they did find were subtle, and in the
relative abundances of individual taxa.
The strong similarities between the Inuit and western microbiomes
surprised Jesse Shapiro, a computational evolutionary biologist at the
University of Montreal, who led the analysis. His team hypothesized that
they'd find greater microbial diversity in the Inuit study population.
"We expected to see a big difference based on what has been seen
in other isolated traditional populations who eat a traditional diet,"
The findings on the Inuit from Shapiro and his collaborators
strongly diverge from that trend. What a person eats helps determine the
microbial population that inhabits their gut. The hunter-gatherer
communities in South America and Africa at the focus of previous studies
eat traditional diets that are high in fiber.
The Inuit, on the other
hand, don't. The Inuit who participated in the study live in the Hamlet
of Resolute Bay, a remote Arctic village with only about 300
inhabitants. Their traditional diet includes raw game (such as caribou,
seal, whale and fish) and few plant-derived foods. It's low in
carbohydrates, rich in animal fats and proteins, and a rich source of
vitamins and minerals.
It's also changing: Shapiro notes that the Inuit diet is
transitioning to become more Western, including more packaged and
The researchers used 16s rRNA sequencing to characterize the
microbial population in stool samples donated by 19 inhabitants of the
Hamlet of Resolute Bay, a Canadian Arctic village on the southern end of
Cornwallis Island accessible only by plane (and, when the sea ice
breaks up, by boat). Shapiro and his team compared the Inuit gut
microbiomes to those in samples from 26 adults in Montreal.
The two groups showed strong similarities in composition and
diversity. At the same time, further analyses did reveal some subtle
differences at the level of individual taxa. The taxa Prevotella, for
example, was found with greater relative abundance - and with greater
genetic diversity - in the Montrealers and the Inuit who ate a Western
diet than in Inuit who adhered to a traditional diet. Previous studies
have associated Prevotella with fiber-rich diets, and the Western diet
includes more fiber than the traditional Inuit diet.
"Our study points to dietary fiber as a major factor driving the overall composition of the microbiome," says Shapiro.
Shapiro and his colleagues say a number of factors might contribute
to the similarity between the Inuit and Western microbiomes. For
example, as the Inuit diet becomes more westernized, the population
faces a rising prevalence of obesity - which has been linked to less
microbial diversity. The effect might also have to do with seasonality.
The Inuit diet changes through the year, and the samples were collected
in the late summer, when the Inuit eat a mix of traditional foods and
those purchased from a supermarket. Shapiro says that collecting samples
during other times of the year, when the traditional diet dominates,
might yield different results.
He sees the study as the first step - but definitely not the last
- toward understanding how the Inuit microbiome and relates to their
diet. "Other communities could be quite different," Shapiro says. "This
is a snapshot at one point in time, of one community, at one time