The Hadza are a small group of hunter-gatherers inhabiting Tanzania’s Rift Valley. While they number just over 1000, fewer than 200 adhere to a traditional lifestyle that includes a diet mainly composed of just five items: meat, berries, a fruit called baobab, tubers, and honey.
Since the Hadza lifestyle does not include refrigerators or supermarkets, their diet fluctuates according to the seasons. This might not be a bad thing, as studies consistently show that these people tend to live long and healthy lives without the use of modern medicine. New research suggests one important reason why this might be the case.
A paper published in the journal Science is the first to show that the gut microbiota of the Hadza population varies seasonally, and that this variation corresponds to their seasonally fluctuating dietary intake.
"Surviving hunter-gatherer populations are the closest available proxy to a time machine we in the modern industrialized world can climb into to learn about the ways of our remote human ancestors," said senior author Justin Sonnenburg, associate professor of microbiology and immunology at Stanford, in a statement.
The findings confirm that the Hadza microbiota is more diverse than, and substantially different from, that of people within industrialized urban areas. These differences can lead to something rather gross in the guts of urban dwellers.
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“The cells that line our guts — the interface between self and other — are separated by a layer of mucin that specialized cells produce,” lead author Samuel Smits of the department of microbiology and immunology at the Stanford University School of Medicine told Seeker. “This mucin is made up of proteins coated in sugars and serves as a protective barrier, among other things.”
“It turns out,” he added, “that if one’s diet is low in fiber, some microbes will begin to consume the mucin that lines our guts.”