Studies show that the gut can play a powerful role in the production of neurotransmitters – ie the chemical messengers our brains and nervous systems use to communicate with each other, like serotonin and dopamine. But it’s not in the way you might think.

While many people cite the gut’s ability to produce serotonin (the feel-good hormone targeted by antidepressants) as one of the key factors in this relationship, Dr Leeming says this isn’t quite the case. “While it’s true that 90% of your serotonin is produced in the gut, serotonin can’t actually cross the blood-brain barrier because it’s too big, so it’s not going to have a direct impact on your mental health in that way,” she explains. “Instead, we think these neurotransmitters may have more of an indirect effect, by signaling to the brain through the vagus nerve.”

But the relationship doesn’t stop there. Perhaps most interestingly, researchers now think that the reason a healthy gut microbiome can boost mood (more on that later), is because your gut microbiome can influence how your body uses the building blocks of neurotransmitters, ie the compounds that make up serotonin and dopamine.

What does the gut-brain axis do? All the benefits of looking after yours