Nervous system
Have you ever experienced a “gut feeling”? What about butterflies in your stomach when you’re getting nervous? You can thank the gut-brain axis for that. Your gut is lined with over 100 million nerve cells that carry messages between your gut and your brain through the vagus nerve, like a super-highway.
This means the health of your gut is affecting countless neurological functions such as mood, stress-response and appetite. Clinically, I regularly see people’s anxiety melt away, depression ease, and stress become manageable once their gut health is restored.
What is the nervous system?
Your nervous system is responsible for communication and regulation throughout the entire body. This complex and intricate system is responsible for everything from heart rate, digestion, and internal body temperature to memory, thought, learning, reflexes, voluntary movement, and more.
The central nervous system is composed of the brain and spinal cord, whereas the nerves that signal throughout the rest of the body make up the peripheral nervous system. The peripheral nervous system is in charge of regulating autonomic function; the processes that are happening in the background when you’re not thinking about them. These functions include:
- Heart rate
- Blood pressure
- Respiration
- Digestion
- Sexual arousal
The autonomic nervous system is split into three divisions; sympathetic, parasympathetic, and enteric.
Sympathetic Nervous System (SNS)
This division of the nervous system responds to stress or danger initiating the fight or flight response. When the SNS is triggered, involuntary responses include changes to heart rate, pupil dilation, blood pressure, body temperature, glucose metabolism, sweating and digestion.
Parasympathetic Nervous System (PNS)
When the PNS is dominating the autonomic nervous system, the body is in a state of rest, digest and reproduce. In essence, this is an energy conservation state when you feel sage and relaxed.
Enteric Nervous System
The ENS is the complex network of nerves that are localized to the gut and control digestion.
How the gut and brain are connected
With the extensive network of nerves housed in the gut lining, there are endless signals sent throughout the body based on the environment within the gut. The gut directly communicates with the brain through the vagus nerve. However, ENS also coordinates messaging with the central nervous system and triggers the release of hormones which can communicate information throughout the entire body. Many researchers now refer to the gut as the “second brain” due to the complexity of the enteric nervous system.
What are symptoms of problems with the gut-brain axis?
If the gut is healthy and balanced, messages sent through the nervous system tell the brain that everything is OK. If the gut is inflamed and imbalanced, the signals can communicate messages that lead to:
- Depression
- Anxiety
- Irritable bowel syndrome
- Inflammatory bowel disease
- CNS diseases
- Autoimmunity
- Cognitive decline
- Skin conditions
How can I support a gut-brain connection?
In a perfect world, your enteric nervous system would be sending your brain signals of safety and security. However, the reality is that threats are unavoidable so maintaining the healthiest and most resilient gut possible means your brain benefits, too. Focus on these gut-healthy habits and your brain will thank you:
- Eat a whole food and low-sugar diet
- Reduce stress and improve coping skills
- Sleep well
- Exercise regularly
- Use probiotics and eat probiotic-rich food
- Protect your gut barrier by avoiding alcohol and medications
- Eat 35-40 grams of fiber/day, 50% from soluble fiber
About Megan Barnett, MS, CNS
Megan Barnett is a functional medicine practitioner in Portland, Oregon. In her clinical practice, she helps patients identify the root cause of their health problems, then designs individualized and evidence-based approaches to alleviate symptoms and help their bodies heal. She has a Bachelor of Science in Dietetics from Kansas State University and a Master of Science in Nutrition and Functional Medicine from University of Western States.