Recent research has uncovered the reason behind the evolution of our brains, pointing to the influence of gut microbes. Specifically, the study suggests that the intestines may have played a key role in boosting energy production over time, leading to the growth of crucial organs.
The study reveals that organisms with larger brains relative to body size, like humans and squirrel monkeys, have higher energy levels compared to those with smaller brains, thanks to their digestive microbes. These microbes help in breaking down food and producing energy efficiently.
This groundbreaking research is the first to demonstrate how the gut microbiome can drive biological differences between animal species.
“The connection between the gut and brain has always been acknowledged on some level. We often refer to ‘gut feelings,’ and it’s known that stress and anxiety can manifest as gut symptoms,” said lead author of the study, Katherine Amato, Associate Professor at Northwestern University, in an interview with BBC Science Focus.
Amato further elaborated, stating, “This study goes beyond that and proposes that the activities in the gut may have laid the groundwork for the evolution of our brains.”
The intestines harbor over 100 trillion microorganisms, a count that surpasses the number of cells in the body. These intestinal microbes collectively weigh around 2 kg (4.4 pounds) – equivalent to the weight of a large pineapple.
Researchers were particularly intrigued by how these tiny gut microbes influence brain size in relation to body size. While humans may not have the largest brains in the animal kingdom, they have a significantly higher brain-to-body ratio compared to other species.
The experiment, detailed in the journal microbial genomics, involved transferring gut microbes from three primate species to mice – two with large brains (humans and squirrel monkeys) and one with a small brain (macaque). The results showed that mice receiving gut bacteria from larger-brained species produced more energy to support brain function, while those with gut flora from smaller-brained primates stored more energy as fat.
Amato explained, “Our findings suggest that as humans and squirrel monkeys independently evolved larger brains, their microbial communities also adapted in similar ways to meet the energy demands.” The study also found that the outcomes of feeding human microbes to mice were more akin to other large-brained species than previously thought.
Researchers are now extending their studies to other primate species to further explore the impact of gut microbes on brain evolution.
About our experts:
Dr. Katherine Amato is an Associate Professor of Biological Anthropology at Northwestern University in Illinois, USA. Her research interests include the gut microbiome, human evolution, and primate ecology.
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Source: www.sciencefocus.com
