Deep in the Peruvian Amazon, researchers have found a hunter-gatherer with gut bacteria different than industrialized nations, possibly explaining the cause of diseases of civilization.
A paper published this week in the journal Nature Communications explained the findings of University of Oklahoma geneticist, Cecil Lewis and his colleagues. Lewis and his team wanted to compare industrialized diets to the diets of ancient humans, and how it effects what is called the human microbiome, the collection of bacteria and microbes present within our guts that help us digest food and fend off diseases.
Lewis took microbiome samples from the digestive tracts of the Matsés, one of the last hunter-gatherer societies, located in the Peruvian Amazon. The diet of the Matsés is far different than our own: whereas we feed on cleaned, processed, and pasteurized food, the Matsés forage for tubers and plantains, and hunt wild meat such as fish, sloth, monkey, and alligator.
Gathering samples from the Matsés and control groups from Oklahoma and a neighboring town in Peru, Tunapuco, Lewis joined the National Health Institute of Peru to compare samples. What they first noticed was that the closeness of one group to another does not necessarily matter. The Matsés contained a microbiome more similar to hunter-gatherer tribes in Africa than with their Tunapuco neighbors. They both were much closer to each other than the processed food eating Oklahomans, however.
One thing the Matsés — and other hunter-gather tribes — have that we do not is Treponema, a group of bacteria that help digest fiber and carbohydrates. In the modern world, we simply do not have them at all.
Lewis compared the findings to results of a 2012 study he performed which looked at the bacteria in fossilized feces from a millennia ago, and found that the human microbiome was similar to the Matsés. “There’s nothing that stands out more than these treponemes,” Lewis said, adding that “they’re clearly common in all traditional diets.”
Lewis now has a direction to take in exploring why diseases of civilization, such as obesity and diabetes, occur at a far greater rate in industrialized countries. “These bacteria co-evolved with primates for millions of years, and now they’re gone from industrialized people,” Lewis reflected. “Why are they absent, and why does that matter?”
His sentiment has been echoed by researcher at the Max Planck Institute for Evolutionary Anthropology Stephanie Schnorr, who noted that when scientists began microbiome research, it treponemes seemed like a small abnormality. Now, however, she says that “we’re realizing that not having treponemes is probably the aberrant thing.”