The brain’s powers are a little overrated. To keep your body going, you don’t need a functioning brain, but you do need something to provide energy. Enter the gut.
Command and control
For instance, the processes the enteric nervous system performs also gives it some control over the trillions of microbes that sit in your gut. Many of them are essential for our health, because they help us extract nutrients that we wouldn’t otherwise be able to, and some even fend off infections.
And there’s more. It had been suspected that what happens in the gut could have an impact on the brain. Now we have found too many correlations to ignore the gut-to-brain connection.
Until now, however, these gut-brain connections have been mere correlations. With some help from tapeworms, a new study changes that.
Tapeworms to the rescue
One of the connecting factors between the brain and the gut has been the immune system. Neurological diseases, such as Alzheimer’s and multiple sclerosis, are linked to changes in the immune system, and auto-immune diseases of the gut, such as Crohn’s disease, are linked to mental illnesses.
She split a group of 30 rats in two: those infected with the Hymenolepis diminuta worm and those without. Then, in both groups, she induced a second infection aimed at increasing the production of a brain signaling chemical called IL-1β. The chemical is usually beneficial, but in excess it can cause damage and has been associated with brain disease.
Good gut, good brain
The reason was that mice with tapeworm infection had already had an immune response, which kept the levels of IL-1β low when a second infection came along. Lower levels of IL-1β in the brain ensured the formation and retention of memories, more than in rats without the worms. Those who hadn’t had the infection produced far greater levels of IL-1β.