The vagus nerve: a key link between gut and brain

Where the vagus nerve runs

Cleveland Clinic explains that there are two vagus nerves, left and right. They leave the lower brainstem and take a long, winding course through the neck and chest into the abdomen, reaching as far as the large intestine. “Vagus” is Latin for wandering.

What it does for digestion

The vagal nerves carry signals in both directions between the brain, heart and digestive system and are a key part of the parasympathetic nervous system, which manages many automatic body functions. Cleveland Clinic notes that damage to the vagus nerve can lead to gastroparesis, a condition in which food does not move normally from the stomach into the intestines. That example shows how much routine digestion depends on these signals.

One route among several

The vagus nerve is only one part of the gut-brain axis. The digestive tract also has its own nerve network, the enteric nervous system, and gut and brain exchange information through hormones, immune signals and substances made by gut microbes. Harvard Health describes this as two-way communication.

“Vagus nerve stimulation” means two different things

Medical vagus nerve stimulation (VNS) uses a device under a doctor’s care. According to Cleveland Clinic, FDA has approved VNS to treat epilepsy and depression that do not respond to standard therapies, and it is being investigated for other conditions.

Social media “vagus nerve hacks”, such as slow breathing, humming or cold water on the face, are different. Slow breathing can be a pleasant way to wind down, but these tips are not the same as a medical treatment, and claims that they “reset” the nervous system go beyond the evidence.

Reading product claims

Be cautious with supplements or gadgets that promise to “activate”, “tone” or “reset” the vagus nerve. Ask what was actually measured, in whom, and whether the claim describes treating a condition. Persistent digestive or mood concerns belong with a qualified healthcare professional.