Gut microbes may have followed migrating humans across continents, study suggests

A new study has found surprising similarities between the gut microbiomes of the Hadza, a hunter-gatherer community in Tanzania, and the Tsimane, a horticulturalist population in Bolivia, according to a report by NPR. The findings raise questions about how human gut bacteria may have traveled alongside migrating populations over long stretches of history.

Comparing distant populations

Researchers examined gut microbiome samples from the two communities, which live on different continents and follow different subsistence lifestyles, one centered on hunting and gathering and the other on small-scale farming. Despite these differences, the study identified notable overlaps in the composition of their gut bacteria, prompting scientists to consider whether these similarities trace back to shared ancestry and historical human migration patterns.

The research adds to a growing body of work exploring the evolutionary relationship between humans and the trillions of microorganisms that inhabit the gut. Scientists have increasingly looked to populations with lifestyles that differ from industrialized, urban societies to better understand the microbiome's natural diversity and its potential links to long-term human health.

What the findings could mean for health research

According to NPR's report, the study's authors suggest that comparing these distant, non-industrialized populations could help scientists understand what a human gut microbiome adapted to historical human lifestyles might have looked like, before modern diets and environments reshaped it. That understanding, in turn, could inform research into the microbiome's broader role in human health and disease.

While the study does not establish a definitive migratory route for these bacteria, its authors argue that the parallels between the Hadza and Tsimane microbiomes support the idea that gut microbial communities may have been shaped, in part, by the movements of early human populations across continents.