I’ve always been curious by the origins of figures of speech such as sayings, idioms and colloquialisms. One set of these that relates closely to mindfulness are those that draw on the coupling or interdependence of the mind and the body, in particular the gastrointestinal system and the brain. 

We know for example that when we say to someone whom we wish to calm down “take a deep breath” we are activating the gastro terminal endings of the vagus nerve in the lower and upper gastrointestinal tract through deep belly breathing to upregulate the parasympathetic nervous system to help restore physical and psychological systems following a flight / fight incident. 

Lately I’ve been exploring sayings like “trust your gut” , or “gut feeling”, “hating someone’s guts”  even the derogatory ‘shit for brains’. Apart from the gut being connected by a two-way nervous superhighway with the brain, there is mounting evidence to suggest that bacteria play a critical role in regulating physical and mental well-being, directly and indirectly playing a role in cognitive performance, anxiety and depression and a whole host of other psychological conditions. Apparently even the bacteria in our poo affects our psychology. So the next time someone calls you shit for brains it may be closer to the truth than you think, not to mention something you have in common with your interlocutor. 

For a relatively recent comprehensive overview of the state of research into this fascinating topic see  https://www.frontiersin.org/articles/10.3389/fnint.2019.00073/full