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Gut Bacteria May Have Traveled With Humans Across Continents
Confirmed
In Short: A new study suggests certain gut bacteria have co-evolved with humans over millennia, traveling with them across continents.
A new study published in Nature suggests that certain gut bacteria have co-evolved with humans over millennia, traveling with them across continents.
According to the study, the Hadza, a group of hunter-gatherers in Tanzania, and the Tsimane, forager-farmers in the Bolivian Amazon, share over 1,200 bacterial species, nearly 90% of which were identified in the highly diverse Tsimane microbiomes.
Justin Sonnenburg, a professor of microbiology and immunology at Stanford University and the study's senior author, says, "If we were inhabited by very similar microbes over a long period of time, it suggests that our human genomes may have come to expect a certain set of microbes and functions."
Sonnenburg and colleagues previously completed a metagenomic sequencing on Hadza samples, showing that the average Hadza individual has about 750 species in their microbiome, while the average Californian has a mere 250.
The study also showed that both the Hadza and Tsimane microbiomes were markedly different from city folk, even those living nearby.
"The microbes are helping us digest foods in our gut, secreting molecules that get absorbed into the bloodstream," Sonnenburg says.
"From a health perspective, is it good or deleterious that industrialized humans have lost a lot of ancestral microbial taxa? We actually don't know," Sonnenburg adds.
"When you start to lose biodiversity in your gut, there may be big issues for your human biology to adjust to and accommodate," other researchers not affiliated with the paper say.
The findings suggest that some strains of gut bacteria have long coexisted with humans, possibly to their mutual benefit.
Experts say the new paper in the journal Nature suggests this microbial kinship may have taken shape long ago, before human migration split these groups' ancestors apart.
"Another alternative is that the industrialized microbiome profile may actually be adapted to an industrialized lifestyle," says Andrew Moeller, an associate professor of evolutionary biology at Princeton University.
What this adds
The study adds to the understanding of how microbial biodiversity loss affects human health.
The research indicates that a diverse gut microbiome co-migrated with humans worldwide and has persisted over millennia.
The study does not definitively prove that these microbes are beneficial or detrimental to human health, but it raises important questions about the impact of modern lifestyles on gut microbiomes.
Background
A new study suggests that certain gut bacteria have co-evolved with humans over millennia, traveling with them across continents.
A new study in Nature indicates that certain gut bacteria have co-evolved with humans over millennia, traveling with them across continents.
What's confirmed
- A new study published in Nature suggests that certain gut bacteria have co-evolved with humans over millennia, traveling with them across continents.
- According to the study, the Hadza, a group of hunter-gatherers in Tanzania, and the Tsimane, forager-farmers in the Bolivian Amazon, share over 1,200 bacterial species, nearly 90% of which were identified in the highly diverse Tsimane microbiomes.
- Sonnenburg and colleagues previously completed a metagenomic sequencing on Hadza samples, showing that the average Hadza individual has about 750 species in their microbiome, while the average Californian has a mere 250.
- The study also showed that both the Hadza and Tsimane microbiomes were markedly different from city folk, even those living nearby.
- "The microbes are helping us digest foods in our gut, secreting molecules that get absorbed into the bloodstream," Sonnenburg says.
- "From a health perspective, is it good or deleterious that industrialized humans have lost a lot of ancestral microbial taxa? We actually don't know," Sonnenburg adds.
- "When you start to lose biodiversity in your gut, there may be big issues for your human biology to adjust to and accommodate," other researchers not affiliated with the paper say.
- The findings suggest that some strains of gut bacteria have long coexisted with humans, possibly to their mutual benefit.
- Experts say the new paper in the journal Nature suggests this microbial kinship may have taken shape long ago, before human migration split these groups' ancestors apart.
- "Another alternative is that the industrialized microbiome profile may actually be adapted to an industrialized lifestyle," says Andrew Moeller, an associate professor of evolutionary biology at Princeton University.
What's still developing
- Studying which microorganisms have been long-term residents of the human gut and may have co-evolved with humans 2, 7, 8 could provide insights into how microbial biodiversity loss affects human health.
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- Image credit: Forster et al., doi: 10.3389/fevo.2026.1895247.
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