Getting To Know Your Second Brain
We have a ‘second brain’: buried in the walls of our intestines are bundles of neurons that make up our enteric (gut) nervous system. Its structure, function, and chemical coding are similar to the ‘first’ brain, but there are more neurons here than either the spinal cord or the rest of the nervous system! Our guts are responsible for a whole lot more than just digestion. The vagus nerve (the longest nerve in the body) is the main ‘highway’ between the gut and the brain. It sends far more information from the abdominal organs to the brain than the other way around. This is part of a feedback loop that has profound effects on our sense of well-being. You know that feeling when your palms are sweating and you have ‘butterflies in the stomach’? It’s looking like our inner organs may turn out to be major sources of information to the brain.
One of the most important origins of the information that travels up the vagus nerve is our gut bacteria, which represent more DNA than in the rest of our body. Remarkably, over 90% of the body’s serotonin is produced in the intestines while gut microbes also make over 30 neurotransmitters (such as dopamine, acetylcholine, and norepinephrine). One important neurochemical is GABA, which has a calming effect on the brain. As we see how interconnected these systems are, we begin to understand just how critical a healthy gut environment is to a balanced nervous system.
The Vagus Nerve: The Body’s Information Express Lane
In its path from the brain, down the body, the vagus nerve touches the muscles responsible for swallowing and speaking (and the gag reflex!), as well as many of the abdominal organs, including the heart, lungs, liver, stomach, and intestines. A main part of our ‘rest and digest’ nervous system, the vagus, is responsible for relaxing blood vessels, activating the salivary glands, and smoothing the path for good digestion. The body’s ability to lower heart rate, blood pressure, and regulate the body’s stress response are closely linked to the healthy function of the vagus nerve. When we are chronically stressed, our bodies spend too much time with the ‘fight or flight’ response activated, which negatively affects vagal activity and slows down our digestion: small wonder that a fast-food burger we chomp down in a hurry can give us such a gut-ache!
Not only a source of information to the brain, the makeup of our gut microbes are one of the biggest influences on the health of this important nerve. Research has found that people with guts that are dominated by ‘bad’ bacteria often have poor activity of the vagus nerve and are prone to mood disorders such as anxiety and depression. These links are so strong that many mental health practitioners are now looking to utilize diet and supplements (such as probiotics) to improve the gut environment, and exercises to improve vagus health as a means to improve mental health.
The good news is that, due to the vagus nerve touching so many places in the body, it’s not difficult to find ways to help it function well. When the ‘express lane’ between the brain and the gut is in good tone, we feel more relaxed and vibrant, more willing to connect with others and able to handle life’s challenges.
Easy Ways To Keep Your Vagus Nerve Healthy
- Washing your face with cold water
- Humming or chanting (vagus is connected to the vocal cords)
- Meditation (promotes positive emotions)
- Slow diaphragmatic breathing
- Gargling water
- Taking bitters, from food or herbal sources (positively affect vagus through digestive organs)
- Balancing your microbiome (with prebiotics and probiotics, from food or supplements)
Understanding that balanced mood and clear mental function have everything to do with the health of your gut-brain connection, there are steps you can take everyday for positive effects on your whole body. Keep your gut microbes happy by eating whole and fermented foods (e.g. vegetables, whole grains, beans, sauerkraut, yogurt and kimchi), take care of your vagus nerve by using the tips above throughout your day, and welcome more calm and connection into your life.