It affects your mood, your sleep, even your motivation to exercise. There’s convincing evidence that it’s the starting point for Parkinson’s disease and could be responsible for long COVID’s cognitive effects. And it sits about 2 feet below your brain.

The gut plays an obvious role in our health by digesting what we eat and extracting nutrients. But there’s a growing appreciation among scientists that our digestive systems affect our general well-being in a much broader fashion. One fascinating aspect of the gut’s widespread impact on health is its direct influence on and communication with the brain, a conduit known as the gut-brain axis.

Through direct signals from the vagus nerve, connects the brain and the gut, as well as through molecules secreted into the bloodstream from our gut microbes and immune cells that traffic from the gut to the rest of the body, our brains and our digestive tracts are in constant communication. And when that communication goes off the rails, diseases and disorders can result.