A new study identifies bacteria in the microbiome that could produce neurotransmitters and potentially influence activity in the brain
The human microbiome—a collection of bacteria, archaea, fungi and viruses commingling in the gut and intestines—has been linked to a wide range of human health conditions, including digestive health and the prevention of autoimmune diseases. Some research has even identified a possible link between gut health and brain function. Building on this work, a study published yesterday in Nature Microbiology reveals that clinical depression could be affected by the amounts of certain bacteria in the gut.
The research team, led by microbiologist Jeroen Raes of the Catholic University of Leuven in Belgium, found that almost all gut bacteria are able to produce neurotransmitters, which are chemicals like dopamine and serotonin that enable communication between neurons. If these “chemical messengers” are sent to receptors in the brain, they can influence mood and behavior. The researchers also identified two strains of bacteria that are lacking in the guts of people who have been diagnosed with depression.
The study adds to mounting evidence that an association between gut health and the brain exists. However, it does not establish whether poor mental health causes depletion of the bacteria, or if the missing bacteria intensifies symptoms associated with mood disorders. More research is needed to conclusively say that gut bacteria influences mental health, says Mark Lyte, a professor of microbiology at Iowa State University who wasn’t involved in the study.
“The studies are just really starting,” Lyte says. “We do not fully understand what all the genes in all the bacteria do, so don’t make the conclusion that we understand everything about the microbiota in terms of their genetic capacity to make [neurotransmitters]. We only understand a fraction of that.” Scientists recently identified more than 100 new species of bacteria in the human gut, underscoring how much we still have to learn about the functions of the microbiome.
Read more: https://www.smithsonianmag.com/science-nature/scientists-find-possible-link-between-gut-bacteria-and-depression-180971411/#zmsZgLlVWgrCB5Zi.99
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