A new study is the first to show how the microbiome—the bacteria that live in the gut—effectively communicates with an organism to affect the host’s metabolism.1
In their recent article, researchers from Flinders University, the South Australian Health and Medical Research Institute, and McMaster University have shown how bacteria living in the mouse microbiome communicate with cells that produce the neurotransmitter serotonin in order to influence blood sugar levels in the host body.

Study coauthor Damien Keating, PhD, professor and head of molecular and cellular physiology at Flinders University and deputy director of the Flinders Health and Medical Research Institute, says the study sheds light on exactly how bacteria in the microbiome communicate to control metabolic glucose levels. The study reveals how gut bacteria affect the normally ‘feel-good’ hormone serotonin to negatively influence blood sugar levels.

“We found that the microbiome worsens our metabolism by signaling to cells in the gut that produce serotonin,” says Keating. “They drive up serotonin levels—which we previously showed to be increased in obese humans—and this rise in blood serotonin causes significant metabolic problems.”

Associated with brain function, serotonin is typically linked to the regulation of sleep, well-being, and metabolism. But the gut actually produces 95% of it, the researchers say.

“The next step will be to understand exactly which bacteria do this, and how, in the hope that this could lead to new approaches to regulating blood sugar levels in humans,” Keating says.

With a better understanding of which bacteria are tied to serotonin production in the gut, treatments could one day be developed to reduce blood sugar levels.

“This is an exciting revelation that can one day have direct implications for human health disorders such as diabetes,” says Keating. “But much more research like this is required in the years to come.”

Reference

  1. Martin AM, Yabut JM, Choo JM, et al. The gut microbiome regulates host glucose homeostasis via peripheral serotonin. Proc Natl Acad Sci USA. 2019;116(40):19802–19804; doi: 10.1073/pnas.1909311116.