Hidden treasure in an Amazon tribe’s poo
The Yanomami have what appears to be the world’s most bacterially diverse innards. Their feces are giving us unprecedented insight into the secrets of the human microbiome — the trillions of microbes that blanket our bodies
In 2008, a military helicopter flew over a wide savanna in southern Venezuela and spotted a circle of grassroof huts, where time had mostly stood still for more than 11,000 years.
It was an “uncontacted” village of Yanomami, a semi-nomadic indigenous tribe spread across the Amazon. When Dr. Oscar Noya-Alarcon arrived the following year — by car, boat and helicopter — he and his medical team became the village’s first contact with modern civilization.
A group of Yanomami men greeted them first, friendly but cautious, followed by rest of the villagers, who curiously poked at the doctors’ beards and shoes. Over four days, the medical team lived with the Yanomami, attended community meetings, performed medical examinations, and treated villagers for pneumonia and other infections.
At some point, they also asked the question: can we have your poop?
“They laugh,” chuckled Maria Gloria Dominguez-Bello, an associate professor with NYU School of Medicine who later analyzed this poop. “They say: You come all this way just to take s---?”
The request would seem bizarre to anyone, Yanomami or otherwise. But for scientists like DominguezBello, Yanomami feces is precious, offering an unprecedented insight into the secrets of the human microbiome — those trillions of microbes that blanket our bodies and are whipping up major excitement amongst biomedical researchers.
Six years later, Dominguez-Bello and an international team of collaborators have released a new study reporting what they learned from the stool, skin and mouths of 34 Yanomami villagers: not only do they have the most diverse microbiomes ever seen, the Yanomami gut also harbours bacteria with antibiotic resistance genes — even though these people have apparently never taken antibiotic drugs.
This adds persuasive evidence that bacteria already have the ability to resist antibiotics, even prior to being attacked by pharmaceutical drugs — a finding that underscores the urgency of the antibiotic crisis, where pathogenic bacteria are developing strategies for defeating even the most powerful drugs on the market.
The paper, published Friday in Science Advances, also compared the Yanomami to more developed societies.
“Perhaps even minimal exposure to modern practices . . . can result in a drastic loss in bacterial diversity,” said first author Jose Clemente, an associate professor with the Icahn School of Medicine at Mount Sinai.
Over the last decade, the nascent field of microbiome research has dramatically shifted our understanding of “what it means to be human,” according to Justin Sonnenburg, a gut microbiome researcher at Stanford University, who was not involved with this study.
“We’re a collection of human and microbial cells,” he said. “By cell number, we’re more microbial than we are human.”
This invisible microbial community also mediates our health and a disturbed microbiome is being increasingly linked to everything from malnutrition to “diseases of affluence,” like obesity, diabetes and even acne. Scientists are therefore particularly keen to understand what a “healthy” microbiome looks like.
One way to answer this question is to study our ancestors’ guts and compare them to modern-day microbiomes, which have been drastically altered by 21st-century practices like antibiotics and Caesarean sections, which deprive newborns of crucial early exposure to bacteria in the vaginal canal.
Short of inventing a time machine, scientists can approximate this by studying the microbiota of traditional populations like the Yanomami, said Sonnenburg, which offer a “precious” study population.
“The world still has a few remote populations of hunter-gatherers that live in the pre-antibiotic era, similar to the way our ancestors lived,” Dominguez-Bello told reporters. “(These) villagers claimed to have never seen non-Yanomami people before.”
The researchers said they are alarmed to see how much bacterial diversity has plummeted in modernday populations. But Patrick Schloss, a gut microbiome expert at the University of Michigan, cautioned it would be premature to conclude that the Yanomami microbiome is somehow superior. “I think that’s really overstating the data,” he said. “I’m sure there are diseases that the Amerindians get that we will never get, in part due to our microbiome.”
The study’s authors hope that by studying populations like the Yanomami, they will gain a better understanding of modern-day diseases like obesity, perhaps paving the way towards better treatments or cures.
Noya-Alarcon, a Venezuelan who has long worked with indigenous communities, said it is also crucial that this research be used to help the Yanomami, especially if they eventually integrate into westernized society. “They need to preserve their inner environment in order to preserve their health,” he said.
“The world still has a few remote populations of hunter-gatherers that live in the pre-antibiotic era, similar to the way our ancestors lived. (These) villagers claimed to have never seen non-Yanomami people before.” MARIA GLORIA DOMINGUEZ-BELLO ASSOCIATE PROFESSOR AT NYU SCHOOL OF MEDICINE