According to new research, communication between the gut and the brain is sophisticated enough to be classed as a new and distinct sense – one capable of affecting our appetite and even our mood.

This two-way link has previously been associated with a variety of health issues, though the physical processes at work have never been clearly identified.

Building on what we already know about our digestive and neurological systems, a team from Duke University in the US traced a series of biochemical actions from the digestive tracts of mice to their brains.