CategoriesVagus Nerve 101

That Gut Feeling: Exploring the Gut-Brain Connection’s Impact on Mood

gut-brain connection

It sounds like the plot of a sci-fi B movie: there’s a tiny brain in your gut talking to the brain in your head — and likely unbeknownst to you — exerting control over your (almost) every move.

But it’s not a movie. It’s science.

And it’s happening to you… right now.

Our brain and our gut, or nervous and digestive systems, are in constant communication with one another, affecting each other in countless ways. You’ve likely felt an inkling of this, such as a “gut” feeling when you were nervous, or perhaps feeling a bit adventurous.[1]

This gut-brain connection is complex and powerful. It impacts everything from our mood to several of our body’s critical systems and functions. Let’s look at the gut-brain connection and why it’s so important to our health and wellness.

Navigating and Understanding the Nervous Systems

Your body always knows the way, and that’s especially true here with the bidirectional gut-brain journey. But explaining your body’s internal cruise control is akin to sharing how to get from Omaha to Jacksonville before Google Maps, MapQuest, or even fold-up gas station maps.

Don’t worry; we’ve simplified the body’s various nervous systems, connections, and functions at play.

Let’s start with your body’s peripheral nervous system, which includes everything excluding the brain and spinal cord. Within this system lies the autonomic nervous system, which regulates our involuntary body functions, including digestion, heart rate, respiratory rate, and more.

The autonomic nervous system has two main parts:

  1. The sympathetic nervous system, which should come with the label “For Emergency, Break Glass,” is what causes us to white-knuckle the steering wheel and give the road ahead uber focus when we hear a crash and see a sea of brake lights ahead. In simpler terms, the sympathetic nervous system is responsible for the ‘fight or flight’ response, triggering physiological changes such as increased heart rate, dilated pupils, and faster breathing that prepare the body to respond to stressful or dangerous situations.
  2. The parasympathetic nervous system is the home of the vagus nerve, which serves as the “modulator” of the gut-brain axis.[2] The vagus nerve controls various vital functions such as heart rate, digestion, and mood, creating a pathway from the gut to the brain and back again. This connects the enteric nervous system (ENS) — our ‘rest and digest’ system — to the brain. The enteric nervous system, with over 100 million nerve cells lining the gastrointestinal (GI) tract, manages digestion and relaxation. That nap you crave after a big lunch? That’s your parasympathetic nervous system at work, slowing your heart rate, relaxing muscles, and revving up intestinal activity. So, go ahead and enjoy that post-lunch recovery, knowing you’re listening to your body.

While focusing on the peripheral nervous system and the vagus nerve’s role in the communication between the brain and gut, we should also note the involvement of supporting systems, including the endocrine and immune systems.[3] These systems contribute to the body’s overall balance and functionality, particularly in the gut-brain connection. This interplay highlights the complexity of the gut-brain axis, but we won’t go over that now, as we’ve already covered a lot in this gut-brain crash course.

The Power of that Gut Feeling

It’s an impressive bi-directional journey, from the gut to the brain and back, and it’s one that you might not even have known about (although you could have had a gut feeling).😉

Both the brain you knew you had and the second brain you just found out about play critical roles in regulating mood, behavior, cognitive function, and stress levels [4] — among numerous other important functions.

And when your parasympathetic system and vagus nerve aren’t getting their job done for any number of reasons, it can have wide-ranging effects far outside your gut. For example, one way this disconnect can manifest is with mental health challenges, such as depressed mood. However, in the same way that our vagus nerve health can be responsible for such conditions, it can also be the pathway to recovery. Numerous studies have linked vagus nerve stimulation to positive outcomes when dealing with a range of neurological conditions. [5]

This very fact implores the Truvaga team to explore vagus nerve science every day and innovate effective and accessible vagus nerve therapy solutions.

So, the next time your mental stress ends up as a knot in your gut or skipping lunch leaves you foggy and fatigued, know there’s a real reason for this connection. The gut-brain journey can come with a heavy toll if you don’t navigate it carefully. You may have assumed as much, but now you have a roadmap for finding your happy place.

[1] John Hopkins Medicine, The Brain-Gut Connection,

[2] Frontiers in Psychiatry, Vagus Nerve as Modulator of the Brain–Gut Axis in Psychiatric and Inflammatory Disorders,

[3] NIH National Library of Medicine, The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems,

[4] Cleveland Clinic, The Gut-Brain Connection,

[5] Frontiers in Psychiatry, Vagus Nerve as Modulator of the Brain–Gut Axis in Psychiatric and Inflammatory Disorders,