If you’ve eaten a fabulous meal recently, the experience was pleasant, comfortable and pain-free because your stomach and intestinal system worked seamlessly to move the food along and eventually absorb it.
Our gastrointestinal tract, or gut, is sometimes described as our “second brain”. This is because it is controlled by its own complex nervous system comprising hundreds of millions of neurons – more than all the nerves in your spinal cord.
But lately we’ve been discovering that it works the other way too: our gut actually has an effect on our brain. And because it’s easier (and generally safer) to manipulate the gut than the brain, this knowledge provides the possibility that doing so could treat some chronic psychological and brain diseases.
Watch: Mia Freedman on how she deals with her anxiety. (Post continues after video).
How your brain affects your gut
Think of a time you had to do an exam and had “the runs” (diarrhoea) or felt anxious and developed butterflies in your stomach. This is your brain driving your gut. If you are stressed or anxious, you even change the production of stomach acid through nerve connections.
Traditionally it was thought gut symptoms came about from an underlying psychological disorder, such as anxiety. Anxiety changes gut function. Over time, this can lead to unpleasant symptoms such as pain, diarrhoea, bloating or excessive fullness.
Many people who suffer from irritable bowel syndrome (IBS) or severe indigestion are anxious, for instance. And doctors have investigated antidepressants and psychological treatments in these disorders with variable success.
But actually many signals go up to the brain from the gut as well as in the downward direction. So could it be that in some cases, changes in the gut are actually driving anxiety experiences rather than the other way around? Accumulating evidence suggests this is likely to be the case. (Post continues after gallery.)