The Brain Gut Connection: It’s Called The Vagus Nerve
Do you ever stop to think about how food makes you feel? Certain foods can cause you joy and excitement just to eat them. Or maybe if you’ve enjoyed too much food, it can make you feel sleepy or make it difficult to concentrate? Have you found yourself searching for quick snacks when you are feeling stressed? Why do we do this??
There are a number of things that contribute to these behaviors and I can’t even begin to cover all of the topics in this blog. However, I’ll start by telling you about one of the anatomical connections between the gut and the brain, and we know that this is definitely playing a large role in some of these behaviors I have described. The anatomical connection I’m referring to is the vagus nerve (also known as the vagal nerves). The nerves connect between the brain, digestive tract, heart, spleen, and more. The vagus nerve makes up about 75% of the parasympathetic nervous system - which is the “rest and digest” mode of our body and the nervous system which controls many involuntary functions of the body such as our heart rate, digestion, and immune function.
As you can imagine, it is important to have good function of our vagus nerve if we want to experience healthy digestion. Since our “rest and digest” function can only occur when we are in a relaxed and non-stressed state, it is important to consider how we are eating. If you are rushing through your meal, or if you are eating in a busy and distracted environment, it might make it difficult to shift our bodies into our parasympathetic nervous system state to allow for good digestion to happen. If we are staying in the sympathetic “fight or flight” state, it leads to feelings of bloating and abdominal pain. For some people, being chronically stressed can lead to Irritable Bowel Syndrome (IBS) which can appear in the form of constipation, diarrhea, or bouts of alternating between the two.
The good news is that we can improve how well our vagus nerve functions. Since the vagus nerve travels through a large muscle under our ribcage - the breathing diaphragm - we can improve the responsiveness of our vagus nerve through practicing good diaphragmatic breathing. It can be especially beneficial to pair these breathing exercises with mindfulness practices. Exercises such as yoga can also have a positive impact on the vagus nerve. Regular physical activities that increase our heart rate and respiration rate, and then allowing for proper recovery also work to improve the function of the vagus nerve. Another interesting point is that there is a lot of newer research that indicates that the food we choose to eat can also impact how well our vagal nerve functions. It is thought that the microbiome of our gut (the types and amounts of bacteria inside of our intestines) can directly affect the vagus nerve and how it communicates with our brain.
The vagus nerve has approximately 90% of the fibers bringing information TO our brain, and the remaining 10% of the fibers bringing information from our brain to the gut. This makes a strong case for how important the signals from our gut to our brain really are. There are “good” bacteria that we need to be living in our gut, and when these good bacteria are not present it has a negative impact on our brain. Mental health disorders such as depression and anxiety may have links to unbalanced gut health. Frustratingly, when we feel stressed and anxious we tend to seek out sugary or highly processed foods to eat rather than healthy snacks. These sugary, or highly processed foods contribute further to having suboptimal “good” bacteria levels. You can see what a vicious cycle this can become!
Instead of reaching for poor nutrition the next time we are feeling stressed and hungry - consider taking a moment to perform a few slow “belly breaths” or diaphragmatic breaths. Take a quick walk - make it an outdoor walk whenever you can to calm your brain with difference sights, sounds, and smells. Find ways to connect with other people. Each of these can help you more easily tap into the vagus nerve - which can help both the gut AND the brain!
If you’re struggling with difficulty in your digestion, or with improving your nutrition, or with motivation to get your body moving - give us a call at SHIFT Physical Therapy and Wellness. We can sit down for a brief, free consultation to see if one of our services at SHIFT would be a good fit for you!
Written by: Renee Hancock, Physical Therapist
