The gut-brain axis seems to be bidirectional—the brain acts on gastrointestinal and immune functions that help to shape the gut's microbial makeup, and gut microbes make neuroactive compounds, including neurotransmitters and metabolites that also act on the brain. In simple terms, the brain and the gut have an intrinsic and delicate relationship. New research is developing around the role our gastrointestinal system plays with optimising mental health. Fascinating!!!
An Interesting article from Scientific American: