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The Vagus Nerve & Gut Brain Axis

The Vagus Nerve

The Vagus nerve is the 10th of 12 cranial nerves, that connect your brain to different parts of your body [1]. The Vagus nerve, also called the pneumogastric nerve or by its roman numeral denominator, cranial nerve X, originates in the medulla; part of the brainstem, and is the longest of the cranial nerves, stretching from your head all the way down through the neck, chest, and abdomen.

Usually, cranial nerves are defined into two categories, sensory or motor, although some can have both functions. Sensory cranial nerves are involved in your senses, e.g., sight, smell, touch, and hearing. Motor nerves control movement and function of muscles and/or glands. The Vagus nerve is an example of a nerve which has both sensory and motor functions.

The Vagus nerve has a wide range of functions throughout the body, including regulating heart rate, breathing, digestion, and immune function. It is also involved in the parasympathetic nervous system, which is responsible for promoting relaxation and restorative functions in the body.

One of the primary functions of the Vagus nerve is to control the heart rate and rhythm. It is responsible for slowing down the heart rate when we are at rest or engaging in activities that don't require a lot of physical exertion. The Vagus nerve also plays a role in regulating blood pressure by influencing the diameter of blood vessels.

The Vagus nerve is also involved in breathing, helping to control the depth and rate of our breaths. It sends signals to the diaphragm and other muscles involved in respiration, helping us to take in oxygen and release carbon dioxide.

Another important function of the Vagus nerve is its role in digestion. It stimulates the production of stomach acid and digestive enzymes, and it also helps to regulate the movement of food through the intestines. The Vagus nerve also plays a role in controlling appetite and satiety, helping to regulate our feelings of hunger and fullness.

In addition to these functions, the Vagus nerve also has a role in the immune system. It is involved in regulating inflammation and helping to fight off infections and diseases. Research has also shown that stimulating the Vagus nerve can have therapeutic benefits for a variety of conditions, including depression, anxiety, and chronic pain [2].

The Gut Brain Axis

The gut brain axis refers to the bidirectional communication between the gastrointestinal system and the central nervous system; via the Vagus nerve [3]. It involves a complex interplay of neural, endocrine, and immune signalling pathways that facilitate the exchange of information between the gut and the brain.

The Gut Brain Axis is the connection between gut health and brain health.

The gut-brain axis serves several functions. One of its primary roles is to regulate digestive processes and maintain homeostasis (maintenance of internal stability while adjusting to changing external conditions) within the gastrointestinal system. This involves coordinating the release of digestive enzymes and hormones, as well as regulating the movement of food through the digestive tract.

In addition to its digestive functions, the gut-brain axis also plays a crucial role in modulating various cognitive and emotional processes. Research has shown that the gut microbiota, which refers to the community of microorganisms that live in the gastrointestinal system (bacteria), can have a profound impact on brain function and behaviour [4,5]. This is because the gut microbiota can produce and release a variety of neurotransmitters and other signalling molecules that can influence the activity of neural circuits in the brain.

How to Help the Gut Brain Axis

To improve your gut health is to improve your brain health. Eating foods that contain or help create healthy gut microbiota is a great place to start:

  • Omega-3 Fatty foods

  • Fermented foods. E.g., Sauerkraut, kimchi, kombucha, kefir, yoghurt. (N.B, these should be found in the chilled section. If they have been heat treated to be stored on a shelf – the good bacteria have all but been killed before they get to you).

  • Prebiotics and Probiotics

  • Polyphenol rich foods. E.g., Nuts and seeds, berries, olives, green tea, cocoa.

  • High-fibre foods. E.g., Fruit and vegetables, whole grains, nuts and seeds.

Other worthwhile supplements for gut health [6-10]:

  • Ashwaghanda - Helps reduce acid levels in the stomach.

  • Lemon balm – Relieves stagnant digestion, eases abdominal cramping, and promotes the overall digestive process.

  • Bilberry – Reduces inflammation in the digestive system.

  • Rhodiola Rosea – Anti-inflammatory and regulates gut microbiome.

  • Turmeric – Regulates gut microbiome, antioxidant and anti-inflammatory.

Another way to help the gut brain axis is to stimulate the Vagus nerve [11]. You can do this by:

  • Meditation / Breath Work

  • Exercise

  • Massage

  • With Music

  • Cold-Water Immersion


Daniel Glassbrook, PhD

Daniel is a sports scientist and researcher, currently working as the first team sports scientist for the Newcastle Falcons Rugby Club, and a postdoctoral researcher in sports related concussion at Durham University.


1. Seladi-Schulman, J. (2022). What is the Vagus Nerve. Healthline. Available at:

2. Tracey, K. J. (2007). Physiology and immunology of the cholinergic antiinflammatory pathway. The Journal of clinical investigation, 117(2), 289-296.

3. Carabotti, M., Scirocco, A., Maselli, M. A., & Severi, C. (2015). The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Annals of gastroenterology: quarterly publication of the Hellenic Society of Gastroenterology, 28(2), 203.

4. Mayer, E. A., Tillisch, K., & Gupta, A. (2015). Gut/brain axis and the microbiota. The Journal of clinical investigation, 125(3), 926-938.

5. Sherwin, E., Dinan, T. G., & Cryan, J. F. (2018). Recent developments in understanding the role of the gut microbiota in brain health and disease. Annals of the New York Academy of Sciences, 1420(1), 5-25.

6. Chakraborty, A. (2022). 12 Incredible Ashwagandha benefits on health – Research backed. Available at:

7. Indigo Herbs. (N.d.). Lemon balm benefits. Available at:,symptoms%20such%20as%20excess%20gas.

8. WebMD. (2022). Health benefits of Bilberry. Available at:

9. Labachyan, K. E., Kiani, D., Sevrioukov, E. A., Schriner, S. E., & Jafari, M. (2018). The impact of Rhodiola rosea on the gut microbial community of Drosophila melanogaster. Gut pathogens, 10, 1-10.

10. Scazzocchio, B., Minghetti, L., & D’Archivio, M. (2020). Interaction between gut microbiota and curcumin: a new key of understanding for the health effects of curcumin. Nutrients, 12(9), 2499.

11. Cleveland Clinic. (2022). 5 Ways to stimulate your vagus nerve. Available at

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