By Brian W. Donnelly, M.D., I.B.C.L.C., Pediatric Alliance — North Hills



Mo Costandi sheds light on fascinating new research looking at the relationship between intestinal bacteria and the brain:

Far from being silent partners that merely help to digest food, the bacteria in your gut may also be exerting subtle influences on your thoughts, moods, and behaviour. And according to a new study from researchers at University College Cork, your gut microbes might affect the structure and function of the brain in a more direct way, by regulating myelination, the process by which nerve fibres are insulated so that they can conduct impulses properly.


All the functions of the microglia cells in the brain have yet to be delineated, but Costandi says they are intimately involved in maturation and development of normal healthy brains:

As master multitaskers, microglia play many different roles. On the one hand, they are the brain’s emergency workers, swarming to injuries and clearing away the debris to allow healing to begin. On the other hand, during times of rest, they are its gardeners and caretakers, overseeing the growth of new neurons, cultivating new connections and pruning back regions that threaten to overgrow. They may also facilitate learning, by preparing the ground for memories to form.


It appears from this new research that gut bacteria have an effect on the microglia. In this study, published last month in Translational Psychiatry, the pre-frontal cortex of germ-free mice was found to be anatomically different than that of normal mice. The germ-free animals had thicker myelin sheaths. They also found that when the germ-free mice were introduced to gut bacteria, the myelin sheath thickness decreased. These findings have potential implications for some diseases, particularly multiple sclerosis, but also for physiologic processes.

Think about your typical adolescent. He seems to have a perfectly normal brain, and yet he sometimes does things that are just so … unmyelinated!

What parent of a teenager hasn’t said that?

Okay — maybe no parent, ever. But that might change as this research continues.


(More “Reflections Of A Grinder” from Dr. Donnelly on The PediaBlog here.)