Breakthrough on link with our ‘second brain’

Australian researchers have made a crucial discovery that sheds light on how the nervous system in the gut communicates with the brain.

It has been well known that nerves from the spinal cord and brain communicate with the gut, but exactly how that interface occurs has not been clear until now.

Australian researchers have made a crucial discovery that sheds light on how the nervous system in the gut communicates with the brain, with implications for the treatment of depression and neurodegenerative diseases such as Parkinson’s through altering the gut microbiota.

It has been well known that nerves from the spinal cord and brain communicate with the gut, but exactly how that interface occurs has not been clear until now.

Several scientific papers posited that there was a direct connection between cells within the gut and the brain and spinal cord, but researchers at Flinders University have now discovered that the communication likely occurs via a process of “diffusion” in which the specialised gut cells, known as enterochromaffin cells, release substances which then act on the sensory nerves that communicate with the brain.

“The gut is the only organ with its own nervous system, known as the enteric nervous system or the second brain,” said study author Nick Spencer from the College of Medicine and Public Health at Flinders University. “We now have a better understanding of how the second brain communicates with the first brain.”

There is two-way communication between the gut and the brain via what is known as the gut-brain axis, which links emotional and cognitive centres of the brain with peripheral intestinal function. Therefore it is believed that what we eat and how that ­affects the gut microbiome can have a direct impact on brain functions such as mood and neurological processes.

The enterochromaffin cells in the gut produce and release hormones and neurotransmitters in response to particular stimuli that are ingested when we eat.

“These EC cells release the vast majority of serotonin into the body, so our study has uncovered a major clue into how the food we eat stimulates the release of serotonin, which then acts on the nerves to communicate with the brain,” Professor Spencer said.

“There is a direct connection between serotonin levels in our body and how we feel.”