The vagus nerve: harnessing the gut-brain connection
Before reading this article, close your eyes and take a few slow, deep breaths. Feel a little calmer? You’ve just tapped into your vagus nerve.
The vagus or ‘wandering’ nerve starts in the brainstem, just behind the ears, and travels down the neck and all through the chest and abdomen, connecting the brain with the lungs, heart, spleen, gut, kidneys and reproductive organs.
As it meanders through the body, it plays an important (though vague) role in a wide range of bodily functions. It is involved in speech, facial expression, eye contact, digestive function, the stress response, heart rhythm and inflammatory pathways, among many other things.
Perhaps unsurprisingly, recent research has shown how this vagabond nerve affects conditions that were originally thought to have no relationship to each other.
Things like reflux disorder, rheumatoid arthritis, atrial fibrillation, depression and migraines may in fact be connected by a single common denominator: the vagus nerve.
Low vagal tone
The vagus nerve is the main nerve of the parasympathetic nervous system, which is most active whilst the body is at rest, such as during digestion or sleep.
It is, therefore, responsible for opposing the sympathetic (“fight or flight”) response led by adrenaline and cortisol to stress, trauma or inflammation. It helps calm us down after a stressful event, lower gut inflammation and overcome pain.
Usually this system works well, but when there is too much stress or tension over a long period of time, the vagus nerve becomes under-stimulated and the balance is disturbed. This leads to low vagal tone, and a variety of unusual symptoms.
These can include (but are not limited to) neck tension, sensations of pressure in the chest, heart palpitations, stomach pain, acid reflux, dizziness or nausea, intolerance to heat or cold, visual disturbances, nervousness and frequent urination.
Inflammation and digestion
The vagus nerve regulates three critical inflammatory pathways in the body, so when there is low vagal tone due to high stress, inflammation goes up.
Two of these pathways are located in the gut – so when vagal tone is low, the movement of the gut and integrity of the gut lining are compromised. This implicates the vagus nerve in conditions like IBS, inflammatory bowel disease, rheumatoid arthritis and small intestinal bowel overgrowth (SIBO).
All sensory information is also relayed via the vagus nerve straight back to the brain. This is why stress plays such an important role in painful digestive disorders like IBS, and stimulating the vagus nerve may well improve symptoms.
Low vagal tone also results in lower levels of stomach acid, which relaxes the oesophageal sphincter and can lead to symptoms of acid reflux.
Inflammation in the gut is likely to affect the brain through the vagus nerve, which is one possible mechanism for its effects on our mood.
However, vagus nerve stimulation has also been shown to increase levels of the neurotransmitters noradrenaline, serotonin and dopamine, which are often low in depression.
It does this by upregulating the nerve cells that produce these happy chemicals, rather than replacing them like conventional antidepressant drugs do.
Vagus nerve stimulation
Aside from expensive devices and treatment, there are a few easy things you can do if you suspect your vagal tone is low.
Preferably in a group, using a wide range of tones and pitches. This directly stimulates the nerve through the vocal chords.~
2. Yoga and meditation
Spiritual practices have a profound effect on stress levels and are of real benefit here.
This is another way of directly stimulating the vagus nerve. Try to gargle for longer than a few minutes at a time, a few times a day.
4. Deep breathing
Breathing deeply for 15 minutes before a meal activates the parasympathetic nervous system and improves stomach acid production, helping to reduce acid reflux among other things.
5. Cotton bud tickling
Due to the position of the vagus nerve just behind the ear, it is possible to stimulate it by tickling the outside of the ear canal with a cotton bud. Another reason to clean your ears!
Herbs are also used to improve vagal tone, and these can be prescribed after a one-to-one consultation.
By Poppy Burr
Poppy, BSc MCPP, is a qualified medical herbalist practising from Aljezur and Praia da Luz. To book a consultation, visit www.poppytheherbalist.com
or call on 969 091 683.