The Vagus Nerve: Essential Knowledge for Your Patients
Most successful systems have a centralized command center that coordinates tasks. The human nervous system is no different. It’s made up of over 100 billion nerves that relay information from the brain to the body and back. But one nerve stands out as a vital command center – the vagus nerve. Few patients are aware of this nerve or the many ways to stimulate and support it for optimal health.
What is the Vagus Nerve?
“Vaga” in Latin means ”to wander.” The vagus nerve is the 10th cranial nerve and originates from a part of the brain responsible for autonomic functions. It is the longest of the cranial nerves, traveling from the brainstem, down the neck, and throughout the body. It has the vital function of innervating several organs, including the pancreas, liver, spleen, heart, and bladder, along with the gastrointestinal lining and lymph nodes. It also influences immune response, digestion, and mental health.
This wandering nerve is an integral part of the autonomic nervous system (ANS), which regulates functions such as:
- Breathing
- Swallowing
- Heart rate
- Blood pressure
- Circulation
- Digestion
- Mood
- Immune response
The ANS has two main divisions – the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The SNS is often referred to as the primitive “fight or flight” response, while the PNS is commonly known as the “rest and digest” response. Both the SNS and PNS are involved when a person is sick or has an infection. The vagus nerve senses when a person is not well and sends signals to the brain.
Another essential function of the vagus nerve is its ability to modulate the activity of the enteric nervous system (ENS), also known as the "second brain." The ENS is a complex network of neurons lining the gastrointestinal tract, which operates somewhat independently but is influenced by the central nervous system (CNS).
The vagus nerve acts as a conduit between the ENS and the CNS, transmitting signals and information. In fact, 20% of the vagus nerve efferent fibers communicate to the organs in the gut, while an astounding 80% of afferent fibers communicate back to the brain. This bidirectional communication between the brain and the gut allows for constant communication and coordination.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5808284/
Research suggests that the vagus nerve plays a critical role in maintaining gut homeostasis by regulating the secretion of stomach acid, digestive enzymes, and bile – ensuring proper digestion and nutrient absorption. The vagus nerve efferent fibers can reduce digestive inflammation and intestinal permeability by reinforcing tight junctions and modulating the gut microbiome. Additionally, the vagus nerve influences the contraction and relaxation of the intestinal muscles – promoting regular bowel movements and preventing constipation.
Beyond digestion, the vagus nerve is involved in modulating inflammation. Vagus nerve afferent fibers stimulate efferent fibers through the inflammatory reflex, which controls innate immune responses, activated by pathogen-associated and danger-associated molecular patterns during an infection.
Communication between the immune system and the brain is vital for controlling inflammation. The vagus nerve regulates immune function and inhibits excessive proinflammatory cytokine production.
An overactive innate immune response can result in continual proinflammatory cytokine activity, resulting in chronic inflammation. This highlights the connection between a dysregulated vagus nerve and inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease, and other autoimmune disorders.
Calming An Irritated Vagus Nerve
Unfortunately, the vagus nerve can become damaged when a person experiences a prolonged period of physical or mental stress, surgery, past or ongoing infections (including dysbiosis), or chronic inflammation, which ultimately negatively impacts their health.
Symptoms of a dysregulated vagus nerve include:
- Gastrointestinal issues – abdominal pain and bloating
- Acid reflux (gastroesophageal reflux disease, GERD)
- Decreased digestion and nutritional deficiencies
- Difficulty swallowing or loss of gag reflex
- Changes to heart rate and blood pressure
- Insulin dysregulation
- Dizziness or fainting
- Hoarseness, wheezing, or loss of voice
- Mood disorders – depression and anxiety
- Fatigue
- Brain fog
When the vagus nerve is not working optimally, the body can lose its ability to switch to the rest-and-digest response, leaving it in a stressed, primitive state.
Stimulation of the vagus nerve has gained attention as a potential therapeutic approach for certain gut-related conditions. Vagus nerve stimulation (VNS), a technique where an implanted device is used to stimulate the vagus nerve, has shown promise in reducing inflammation and improving symptoms in conditions like irritable bowel disease, depression, and anxiety.
Ten Ways to Shift a Dysregulated Vagus Nerve Back into Balance
The vagus nerve can also be stimulated with a variety of techniques and practices that can be easily integrated into daily routine, including:
- Breathing – Deep, slow breathing promotes a relaxed parasympathetic, rest-and-digest state.
- Meditation – Slow breathing and focused concentration can help calm the mind and reduce stress. Even a 5-10 minute guided meditation can be effective.
- Exercise – Walking, light jogging, swimming, bike riding, yoga, or tai chi – moving the body in a way that is enjoyable.
- Singing, chanting, humming – This activates the vocal cords and muscles at the back of the throat, which stimulates the vagus nerve.
- Laughing – Anything that brings joy and positive emotions can help improve the vagus nerve.
- Cold water therapy – Place a cold compress on the back of the neck or chest for several seconds to up to 15 minutes. Or, end a shower with 40-60 seconds of cold water.
- Gargling – Gargle loudly with cold water for 30 seconds in the morning to activate the vocal cords.
- Eat a balanced diet – Fibrous foods and whole foods rich in probiotics (natto, kimchi, organic miso) and omega-3s (wild-caught salmon, walnuts, chia seeds, avocados) feed the gut’s beneficial bacteria, which nurtures a healthy gut microbiome and vagus nerve.
- Probiotics and other supplements – Supplementing with probiotics can play an important role in the bidirectional communication between the gut and brain. Research shows that some probiotic supplements can improve vagus nerve tone. Glycine and ginger have also been shown to support vagus nerve health.
- Fasting – Fasting for an extended period activates the parasympathetic nervous system, resulting in increased heart rate variability (HRV). People with an increased HRV are typically more resilient to stress, which is associated with a healthy vagus nerve.
This wandering nerve deserves a lot of attention since it can influence the maintenance of gastrointestinal health, stress-induced and inflammatory diseases, immune responses, mental health, and overall health and well-being. By recommending a few simple strategies, you can help your patients give the vagus nerve the care and support it deserves.
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References:
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5859128/
- https://www.ncbi.nlm.nih.gov/books/NBK537171/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4858318/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5673632/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5808284/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4082307/
- https://www.jnmjournal.org/journal/view.html?doi=10.5056/jnm16018