The Foundational Role of the Vagus Nerve

The role of the vagus nerve in neurodevelopment and the health of our children couldn’t be more important. If the vagus nerve isn’t functioning optimally there can be a cascade effect on their health and development and there will be a major block to sustained progress in many interventions you may be using. Let’s review together the foundational role of the vagus nerve in our children’s health and development.

What is the vagus nerve?

The vagus nerve is the tenth (X) cranial nerve and is the longest nerve in the body. It originates in the brainstem and then, like its Latin name implies, it wanders through the body connecting to the organs throughout the entire body. The vagus nerve is a complex bidirectional system which means it is made up of both efferent and afferent nerves that link the brainstem to various organs.  Efferent nerves are motor nerves that carry messages from the brain to the muscles and organs. Afferent nerves are sensory nerves that carry messages from sensory receptors back to the brain.

What is the vagus nerve's role in the nervous system?

The vagus nerve plays a role in the part of the peripheral nervous system known as the Autonomic Nervous System (ANS) which is responsible for automatic or involuntary physiological response throughout the body such as heart rate, respiration, blood pressure and digestion. The ANS is made up of three parts: the Sympathetic Nervous System (SNS), the Parasympathetic Nervous System (PNS) and the Enteric Nervous System (ENS).¹

The understanding of the importance of the vagus nerve continues to evolve. One of its most important functions is its role in the digestive system via the Enteric Nervous System and the body’s ability to appropriately switch between a Sympathetic nervous state (fight or flight) and a Parasympathetic nervous state (rest and digest). 

One of the areas of keen study on the vagus nerve is its role in the gut-brain axis. Digestion is a north-to-south process in the body and digestion starts in the brain. For example, if your child is struggling with switching from a sympathetic state to a parasympathetic state, then they will likely have chronic digestive problems as the digestive cascade will not have been appropriately triggered which will lead to downstream digestive dysfunction. 

In addition, the Enteric Nervous System is the nervous system of the digestive system. An example of the role of the vagus nerve to gut function is when the efferent vagus nerves send signals to the Enteric Nervous System which in turn send signals to the muscles of the digestive tract to initiate peristalsis (move the food along the digestive tract). If the vagus nerve is not functioning optimally this can result in several digestive challenges including but not limited to constipation.²

As the vagus nerve impacts gut function, it can result in gut dysfunction such as dysbiosis and leaky gut which in turn have been shown to have a significant impact on brain function.

What are the signs and symptoms of vagus nerve dysfunction in children?

• Gastroparesis (in severe cases of vagus nerve impairment)
• Constipation
• Requiring constant digestive supports (enzymes)
• Low heart rate variability (HRV)
• Poor or overactive gag reflex
• Difficulty swallowing
• A child that is having difficulty with toilet training
• Speech delays 
• Delays in walking or crawling

What can you do to improve vagal tone in children?

This is a tricky one. Most of the typical suggestions that work would be difficult to implement with children, although the list below includes them as it really depends on the age and development of each child. 

This list is not exhaustive and there is always debate over which methods are most effective and can really improve vagal tone and elicit positive neuroplasticity. There is evidence, however, that using a multimodal approach can have positive effects.³

• Gargling
• Triggering the gag reflex
• Singing loudly
• Coffee enemas
• Vagal Nerve Stimulation – there are several different tools available these days that use electrical stimulation and/or vibration
• Low level laser⁴

Other things we can do to help stimulate the vagus nerve:

• Infant massage and swaddling⁵
• Probiotics – in particular Lactobacillus Rhamnosus and Bifidobacterium Longum have been shown to act through the vagus nerve to lessen symptoms of anxiety and depression⁶⁷
• Omega 3 Fatty Acids⁸

What to do next?

If you want to learn more about the role of the vagus nerve and the gut brain axis, I encourage you to watch the free expert interview replays on The Anxiety Summit 5 with Dr. Navaz Habib, the author of the book Activate Your Vagus Nerve: Unleash Your Body's Natural Ability to Heal  and the interview with Dr. Datis Kharazzian, author of Why Isn’t My Brain Working.

I hope this introduction to the importance of the vagus nerve has been helpful. Take the next step and watch the expert interviews by signing up here.

1. Waxenbaum JA, Reddy V, Varacallo M. Anatomy, Autonomic Nervous System. [Updated 2021 Jul 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-
2. Why Isn’t My Brain Working?, Datis Kharrazian,DC, PhD, Page 165-166.
3. Engineer, C.T., Hays, S.A. & Kilgard, M.P. Vagus nerve stimulation as a potential adjuvant to behavioral therapy for autism and other neurodevelopmental disorders. J Neurodevelop Disord 9, 20 (2017).
4. Machado, Calixto & Machado, Yanin & Chinchilla, Mauricio & Foyaca-Sibat, Humberto. (2019). Vagal Nerve Stimulation With Low Level Lasers Of Two Different Frequencies, Assessed By QEEG. Internet Journal of Neurology. 21. 1-9. 10.5580/IJN.54122
5. Field, Tiffany, and Miguel Diego. “Vagal activity, early growth and emotional development.” Infant behavior & development vol. 31,3 (2008): 361-73. doi:10.1016/j.infbeh.2007.12.008
6. Bercik, P et al. “The anxiolytic effect of Bifidobacterium longum NCC3001 involves vagal pathways for gut-brain communication.” Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society vol. 23,12 (2011): 1132-9. doi:10.1111/j.1365-2982.2011.01796.x
7. Javier A. Bravo, Paul Forsythe, Marianne V. Chew, Emily Escaravage, Hélène M. Savignac, Timothy G. Dinan, John Bienenstock, John F. Cryan. “Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve”. Proceedings of the National Academy of Sciences Sep 2011, 108 (38) 16050-16055; DOI: 10.1073/pnas.1102999108
8. Christensen, Jeppe Hagstrup. “Omega-3 polyunsaturated Fatty acids and heart rate variability.” Frontiers in physiology vol. 2 84. 16 Nov. 2011, doi:10.3389/fphys.2011.00084