Introduction
One of the things I enjoy talking about with people the most is the impact that our nervous system has on our digestive function. So much so, that most of the time I meet with people, we are getting into some of the nitty gritty of the interrelationship between these interwoven systems.
The human body is a vast network of connections, and one of the most fascinating (and complex!) connections is the intricate relationship between the nervous system and digestion. While we often think of digestion as a purely mechanical process that occurs in the stomach and intestines, it’s important to recognize that the nervous system plays a crucial role in orchestrating and regulating every step of this essential bodily function.
The Enteric Nervous System: The Brain in Your Gut
When we talk about the connection between the nervous system and digestion, we can’t overlook the enteric nervous system (ENS). Often referred to as the “second brain,” (and, in fact, derived during development from vagal nerve cells) the ENS is a complex network of nerves that extends throughout the digestive tract, from the esophagus to the rectum. This network contains over 100 million neurons, making it larger than the spinal cord. Its role is to control the digestive process independently, but it also communicates extensively with the central nervous system (CNS), which includes the brain and spinal cord.
That brain-gut connection is a two-way street. While the CNS sends signals to the ENS to initiate and regulate digestion, the ENS also sends feedback to the brain, providing information about the state of the digestive system. This bidirectional communication is facilitated by a complex network of nerves, hormones, and neurotransmitters. Much of that communication is done via the vagus nerve; a cranial nerve that connects the CNS directly to the ENS. It plays a crucial role in controlling digestive processes such as gastric acid secretion, gut motility, and even the release of certain hormones. Moreover, the vagus nerve is involved in conveying sensations of fullness and satisfaction after eating.
Stress and Digestion: The Fight or Flight Response.
One of the most well-known ways the nervous system affects digestion is through the “fight or flight” response. When the brain perceives a threat or stress, it triggers the release of stress hormones like cortisol. These hormones can impact digestion by reducing blood flow to the digestive organs, slowing down or even temporarily halting digestion. This is why you might experience a loss of appetite or stomach discomfort during stressful situations.
As I like to say, “If you’re in fight or flight, you will NOT be in rest and digest…and your body will choose fight or flight every single time for survival!” In our busy lives as we run to-and-from appointments and meetings, eat on-the-go, and even in front of screens, that constant stress state impacts how efficiently we digest food. So much so that if you’re experiencing digestive issues like bloating, nausea, constipation or even diarrhea, this is where I recommend you start: take some deep breaths or use other tools to help support your nervous system before eating. That way, you can help shift from more of a fight or flight response to a body that’s primed to digest well! You never know – stress really could be the thing impacting your digestive system the most. Instead, when the body is in a relaxed state, the digestive system is activated, promoting optimal digestion (and absorption!). Part of that is the very unpopular opinion to take time away from screens while you eat! Even something that isn’t inherently stressful like a horror movie or work deadline still causes rapid eye movement that stimulates the fight or flight response.
Conclusion
The intricate relationship between the nervous system and digestion highlights the remarkable coordination that takes place within the human body. While digestion may seem like a straightforward mechanical process, it is in fact a dynamic and finely-tuned dance between the central nervous system, the enteric nervous system, and various hormones and neurotransmitters. We will give into some of those neurotransmitters in future blog posts! But for now, understanding the basics of the gut-brain connection is crucial not only for maintaining healthy digestion but also for promoting overall well-being. Stress management, relaxation techniques, and mindful eating can all contribute to a harmonious balance between the nervous system and digestion. So, the next time you enjoy a satisfying meal, take a moment to appreciate the intricate symphony of signals and responses that allow your body to digest, absorb, and utilize the nutrients it needs to thrive. If you want to learn more about your nervous and digestive system through individualized testing and care, book a visit with one of our amazing providers HERE!
