The Vagus Nerve (Cranial nerve X) is the longest of the 12 cranial nerves and plays a HUUGE role in the body’s functions. First of all, the Vagus nerve is a neuromodulator which has motor and sensory fibres connects the brain stem including having effects on regions of the brain to heart, lungs, stomach, large intestine, small intestine, spleen, liver, gallbladder, ureter, female fertility organs, kidneys, ears, tongue and is the main parasympathetic nerve in the body. Recently it was found that stress directly inhibits the Vagus nerve…. Hmmm interesting what are all the symptoms of stress compared with Vagus nerve dysregulation? You would have to be splitting hairs to draw a difference.
This nerve is grossly underappreciated and utilised even with the growing body of evidence showing major improvements in gut health, mental health, cardiac health, inflammatory disorders, autoimmune conditions and epilepsy. Vagus Nerve stimulation may involve manual manipulation of the nerve in the neck, exercises which strengthen Vagal tone, neural tensioners and electrical stimulation with auricular clips (transcutaneous vagus nerve stimulation) or electro needling. Stimulation of the Vagus nerve improves its afferent and efferent nerve fibres which improve negative feedback loops (If its too high brings it down and if its too low brings it up).
As well as tVNS there are a variety of things which can be done to increase vagal tone with some being more affective for particular conditions than others. Exercises such as gargling, gag-reflex, singing, uvula elevations, meditation and putting the face in a bowl of ice water (divers reflex) all upregulate vagal tone and improves its functions.
So what can we treat with non-invasive tVNS?
Behavioural Issues (e.g. autism)
Blood Brain Barrier
Neuroplasticity via BDNF (stroke, rehabilitation)
So how can the Vagus nerve treat the gut?
The Vagus nerve is what modulates the release of hydrochloric acid (stomach acid) and digestive enzymes Gastrin and Leptin in the stomach, when there is too much hydrochloric acid in the stomach the Vagus nerves afferent fibres perceive this and inform the brain to make a change. An efferent message is then sent down the efferent fibres of the Vagus nerve and levels of hydrochloric acid are adjusted to suitable levels. The same can also be said when there is too little hydrochloric acid when we get slow digestion and bloating as a result. The Vagus nerve also has a motor role and that is it sets the tone of the pyloric sphincter which is the sphincter between the oesophagus and the stomach. When this is weak as a result of Vagus dysregulation, stomach acid can travel up the oesophagus causing heart burn and chronically Barret’s oesophagus. It has also been found that tVNS increases gut permeability, improves peristaltic activity and treats inflammatory gut disorders such as Celiac, SEBO and ileitis.