The gut-brain axis involves the connection of the gut to the brain. This connection goes in both directions—from the brain to the gut and from the gut to the brain. In one way, the gut-brain axis is connected by the vagus nerve—a large nerve connecting the brain to the intestines and other organs. The vagus nerve both sends messages to various organs, and also receives messages from these organs—including the gut—to send to the brain. A new study has established the vagus nerve as a main form of communication from the gut bacteria to the brain.
In an animal model, researchers were able to show that mice fed the probiotic Lactobacillus rhamnosus JB-1 showed less stress-, anxiety-, and depression-related behaviors than did mice not fed the bacteria. Further, the probiotic mice had lower levels of the stress hormone corticosterone, and they also experienced changes in the expression of receptors of the neurotransmitter GABA (gamma-aminobutyric acid) in the brain—highlighting the ability of probiotics to directly affect brain chemistry under normal conditions.
This is an early study that will need to be replicated in humans, but studies like these pave the way for our understanding of the complexities of the gut connection. Did you ever think your gut could have such an effect on your health? If you read my blog regularly, I sure hope so!