New Delhi: There is no doubt about the benefits of modern medicine. And yet, as soon as the body interacts with medication, the human microbiome suffers, says a study published on 20 May in the Cell Press journal Cell Reports.
“The study gives us a better idea of how sensitive human gut microbes are. It opens the door for future research on how we can restore our microbiota after using medicines like antibiotics, which can deplete organisms in our gut,” corresponding author Maria G Dominguez-Bello of Rutgers University in New Jersey said in a press release.
Several studies have shown that the human gut microbe is sensitive and can be affected by urbanisation, diet, lifestyle changes, and even the environments people live in. However, it has been hard for scientists to isolate what impacts gut microbes since most of these influences overlap.
‘A rare experiment’
For the study, titled ‘Rapid microbiome restructuring associated with medical exposure in remote Amazonian Indigenous communities’, researchers from the Rutgers University in New Jersey travelled to a remote corner of the Amazon rainforest.
According to researchers, there are over 45 indigenous nations living in Venezuela’s remote areas, which can only be reached via river or air. These nations are considered sovereign communities having their own culture, language, and governance, which have existed for decades unaffected by the emergence of modern countries.
These communities rely on fishing, hunting, and gathering to survive, and their traditional lifestyles and diets have remained unchanged over time. However, in the past decade, doctors from the World Health Organization (WHO) have begun quarterly visits to these communities to treat and prevent onchocerciasis, or river blindness, a parasitic infection found in African and Latin American countries.
In 2015, when the WHO programme was just beginning, researchers saw it as an opportunity for a “rare natural experiment”.
“We know from studies in urban societies that antibiotics can have huge impacts on gut microbes,” Dominguez-Bello said. “But we didn’t know how even basic medicine might affect people with very limited exposure to medicine.”
The team of researchers then visited the settlements along with doctors first in October 2015 and then in February 2016. They collected samples from the gut, mouth, nose, and skin of 335 participants.
They found that within four months of the first medical visit, the indigenous people’s gut microbial diversity declined. Bacteria that are generally associated with digesting fibre, such as Prevotella and Treponema, diminished.
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Reviewing medicines
Researchers said that while such WHO programmes treating infectious diseases offer life-saving benefits, the treatments could be redesigned to prevent a negative impact on gut bacteria.
“Many conditions, from obesity to allergies and even some cancers, are linked to gut microbes. Understanding how to protect and restore microbial diversity could become an important part of improving our health,” said Dominguez-Bello.
Not only are gut bacteria vital for breaking down indigestible fibres, absorbing vitamins, and regulating the immune system, studies are also linking it to mental health.
Researchers highlighted that such studies could be the starting point to review the kind of medicines that are known to kill gut bacteria. These medicines could either be altered to be less harmful, or new medical research could find ways to replenish the lost gut bacteria.
(Edited by Aamaan Alam Khan)