Our nervous system and the microbiome
Do you go with your gut feeling? Actually, this old proverb harbors more truth than you think. Your gut influences your feelings and your brain controls your gut through the gut-brain axis. A big part of this communication involves your microbiome. The most important link between the gut and the brain is the vagus-nerve. It controls salivation, the heartbeat and digestion. Vice versa, the gut tells the brain “I am full and I feel good”, or a calm heartbeat signals that you are relaxed… The messages this nerve receives come from the metabolites of your gut microflora and from messenger substances in your gut immune- and hormone-cells. The messenger substances from your gut immune- and hormone-cells are in turn dependent on your gut microbiome. Another route to the brain is via the blood, through which hundreds of thousands of bacterial metabolites travel your body.
Experiments with mice have proven the connection between the gut microbes and the brain. A transfer of gut bacteria from docile mice to anxious mice made the anxious mice fearless. The first trials with humans are currently underway. So far, the administration of yoghurt and probiotics have shown a positive influence on one’s mood. If all these indications are taken together, one could imagine that, in the future, psychiatrists will first screen their patients suffering from depression for their gut microbes in order to feed the good microbes which are missing. Until then, eat healthy!