Impact of Seasonal Inuit Diet on the Microbiome

Research Overview

To explore how the Inuit diet influences the microbiome, researchers conducted a comparison of fecal bacteria between the Inuit population and city-dwelling Canadians. The human digestive tract hosts a diverse array of microbes, including bacteria, fungi, and viruses, collectively known as the gut microbiome. Studies have demonstrated that the composition of these microbes significantly affects various aspects of human health, including weight, metabolism, immune function, and mental well-being.

Dietary Influences on the Microbiome

The gut microbiome is influenced by dietary choices, which can vary with seasonal availability of food. A research team in Canada sought to investigate the microbiome differences between the Inuit, indigenous inhabitants of the Arctic regions, and urban dwellers from Montreal. Traditionally, the Inuit maintain a hunter-gatherer lifestyle, relying heavily on an animal-rich diet that includes seal, caribou, wild birds, and fish. Approximately 75% of their caloric intake comes from animal fat, contrasting with the typical city dweller, who derives about 35% of calories from fat and 50% from carbohydrates.

Study Methodology

To assess the impact of dietary differences on microbiome composition, the Canadian research team collected monthly stool samples from 15 Inuit individuals and 9 Montreal residents from July 2015 to February 2016. Their findings were published in the journal Microbiome.

Key Findings

The study revealed slight variations in the overall bacterial composition between the two groups, with dietary factors accounting for 11-17% of this variation. In contrast, geography and sex contributed minimally, only accounting for 3-5%. Interestingly, Inuit individuals who adopted more Westernized diets exhibited microbiomes more similar to those of their Montreal counterparts and vice versa.

Regarding seasonal changes, the researchers observed no significant differences in the microbiomes of the Montreal participants and only minor variations among the Inuit, indicating that microbiomes tend to remain stable unless there is a substantial dietary shift. Most of the observed variation was attributed to individual differences, ranging from 45-61%. These individual differences were not linked to diet, sex, or geographical location, suggesting they may stem from inherent genetic diversity or unmeasured factors, such as age.

Conclusions and Future Research

The adage “you are what you eat” appears to hold true, as this study indicates that diet has a more profound effect on microbiome composition than geographical or biological factors combined. The researchers aim to expand their investigation by incorporating additional variables, such as age, into their analysis. As globalization progresses and diets worldwide become increasingly Westernized, further research is essential to understand how these dietary changes may influence the human microbiome and overall health.

Written by Calvin J. Chan, B.Sc.
Reference: Dubois, G., Girard, C., Lapointe, F., Shapiro, B.J. (2017). The Inuit gut microbiome is dynamic over time and shaped by traditional foods. Microbiome. 5: 151