Researchers collect poop from Inuit for microbiome study

A Canadian researcher, referred to by some in Nunavut as "the poop lady," is studying how the digestive microbiome in Inuit may differ from other Canadians.

Her main source of research, you ask? Well, people's poop, of course.

According to the study, the types of microbes living in the digestive tract contribute to immunity, nutrition, and behaviour and vary with diet, lifestyle, and disease.

Catherine Girard, a PhD student at the Université de Montréal, collected stool samples from people in Resolute, Nunavut. Of the roughly 200 people who live in the hamlet, Girard gathered samples from 19.

"This helped us get a snapshot of the Inuit microbiome," she said, adding "This is obviously specific to the 19 people who contributed samples in Resolute Bay and we can't extrapolate this to everyone living in Nunavut and your microbiome will change a lot depending on your personal health, your diet."

The following has been edited and condensed.

Q. How did people react when you asked them to take part in the study?

A. People were generally surprised and taken aback about what I study, but they thought it was funny and interesting. Most people (even those who chose not to participate) were interested in the background of the study and on the potential results.

I'd like to underscore the support that we got from the community of Resolute Bay, both from the HTO and from the hamlet office, and also from the residents who welcomed us year after year, and from our field assistants who helped us recruit volunteers. The project could never have happened without them.

Q. How did you collect the samples?

A. For sample collection, once someone was recruited and accepted to participate in the study, I would give them a 'sampling kit'. This kit was a bag contained a specimen container, a pair of sterile gloves, instructions in English and Inuktitut (mostly recommending that the sample not touch the water in the toilet) and toilet paper.

I would leave this kit with participants, who would deposit their stool sample in their specimen cup. Afterwards, I asked people to leave their sample outside where it was cooler. I would stop by the next day (and the following, if needed), to collect the sample and complete a dietary habit questionnaire, to see what people had eaten in the past few days.

Q. How do you know 19 samples will be enough for the study?

A. The number of samples we collected in Resolute resembles the numbers typically collected in this type of study. It may not seem like a large number, however Resolute Bay does not have a very big adult population (I think the Statistics Canada census of 2011 put the adult population at 145), and we do have certain exclusion factors for our study. For example, people who recently took antibiotics could not participate, because antibiotics change the gut microbiome.

Q. What did you learn?

A. We found that the gut microbiomes of the Inuit in Resolute Bay were surprisingly similar to those of Montrealers we also sampled. In terms of broad composition, they were very similar. We think this might be due to similar consumption of market foods in both groups. However, we did find differences in the abundance and diversity of certain types of bacteria between both populations.

For example, we found that bacteria associated with meat consumption were more abundant in Resolute Bay microbiomes, and that these samples also had fewer and less diverse bacteria involved in degrading dietary fibre. Meanwhile, our Montreal microbiomes contained more bacteria associated with dairy product and citrus fruit consumption.

Q. Was this what you had expected?

A. The similarities of the Resolute Bay microbiomes to Montreal microbiomes surprised us: however, all our samples were collected in the first two weeks of August. We wondered if the seasonality of the traditional Inuit diet, with variable availability of prey over the course of a year, might mean that the Inuit microbiome is more different from Montrealers at other times of the year.

To check this, my colleague at the Université de Montréal Geneviève Dubois sampled the microbiomes of residents of Resolute Bay every month over the course of the year, to see how a changing seasonal diet could induce seasonal change in the microbiome. Her research is currently underway.

I am also interested in how the gut microbiome may interact with mercury that is ingested we traditional food. We know that the benefits of consuming country food outweigh issues related to mercury. However, it is possible that some mercury may be absorbed, and I am interested in understanding how the microbiome might be involved in the fate of mercury in the body.

We think this may be possible because bacteria are responsible for many transformations of mercury in the environment, and if these transformations also occur in the microbiome in our guts, it might affect how mercury is absorbed or excreted by the body. To do this, I am looking for bacteria in the microbiomes we sampled that might have these genes capable of interacting with mercury. This research is currently underway.