The researchers suggest that the SCFAs have an effect in the brain in reducing feelings of anxiety – as well as in preventing the gut from ‘leaking’. The inside of the bowel is lined by a single layer of cells that make up the mucosal barrier, between the inside of the gut and the rest of the body. This barrier is effective at absorbing nutrients, but prevents most large molecules and germs passing from inside the bowel into the bloodstream and potentially causing inflammation.