The Gut-Brain Connection: The Link Between Stress and Digestion

Life is a highway. And as it turns out, so is your gut.

Between the brain and the digestive tract lies a bidirectional highway of neural pathways and chemical messengers that are constantly communicating. This intricate system is known as the gut-brain axis, and it has become a rapidly growing area of scientific research.

As scientists continue to explore this connection, they’re discovering that it influences far more than digestion. Signals traveling between the gut and brain help shape our mood, stress response, immune function, and many aspects of our overall wellbeing.

In this blog, we’ll explore that two-way connection between the brain and the gut, learn how the vagus nerve helps relay critical information along the way, and why supporting one side of the equation can benefit the other. Research increasingly shows that when we improve our digestive health, we often support our stress resilience too, and vice versa.

Understanding the Enteric Nervous System (ENS) AKA The “Second Brain”

The digestive system is complex. Coordinating the movement of food, nutrient absorption, and interactions with the immune system requires an extraordinary amount of regulation. So much so that the gut has its own dedicated nervous system: the enteric nervous system (ENS).

Often called the body’s “second brain,” the ENS contains hundreds of millions of neurons embedded throughout the walls of the gastrointestinal tract. It can operate largely independently to manage digestion, regulating processes such as intestinal motility, enzyme secretion, blood flow, and local immune responses. This local control allows the gut to respond quickly and efficiently to the changing demands of digestion without waiting for instructions from the brain.

But the ENS does not work in isolation. It communicates continuously with the central nervous system through the gut-brain axis, a two-way highway of signals that links digestive processes with mood, stress response, and overall homeostasis. In other words, the brain influences the gut; and the gut sends information back to the brain. [1]

This constant communication helps explain why stress, emotions, and lifestyle factors can influence digestion, and conversely, how gut health can affect mental wellbeing. Later in this series, we’ll explore the role of the gut microbiomeand how maintaining microbial balance supports both gut and brain health.

But first, let’s zoom in on one of the most important pathways along this highway: the vagus nerve, which acts as a superhighway for signals traveling between the gut and brain.

The Vagus Nerve: The Gut-Brain SuperHighway

The vagus nerve is a central player in many systems throughout the body. Running from the brainstem down to the abdomen, this “wandering nerve” helps transmit signals between the gut and the brain. It’s also the longest cranial nerve in the body, connecting the brain to multiple organs along the way.
Because of these wide-ranging connections, the vagus nerve plays a major role in the gut-brain axis, helping relay information that can influence digestion, mood, behavior, and cognition.

Interestingly, most of the communication traveling along the vagus nerve actually goes from the gut to the brain. In fact, about 80% of the nerve fibers carry signals upward, sending constant updates about digestion, microbial activity, and immune signals. The brain then uses this information to adjust how the body responds. [2]

The vagus nerve also helps regulate the autonomic nervous system (ANS), which controls many automatic bodily functions. You can think of it as helping manage the body’s “gas and brake.” It plays a key role in balancing the sympathetic nervous system (the fight-or-flight response) with the parasympathetic nervous system (rest-and-digest mode).

When vagal activity is strong (often referred to as high vagal tone), the body is better able to regulate stress responses, inflammation, and digestion. Lower vagal tone, on the other hand, has been associated with digestive disorders, heightened stress responses, and reduced heart rate variability (HRV), a marker of how well the body adapts to stress. [3]

Because of this connection, a growing number of interventions aim to support or stimulate the vagus nerve. Practices like breathwork, relaxation techniques, and other lifestyle strategies can help improve vagal tone, supporting both digestive function and stress resilience. (We’ll explore some of these practical approaches in the recommendations section.)

Stress, Cortisol, and Digestion: How Mindfulness Can Help

Stress is not just in your head; it affects your gut as well. When your body encounters a stressor, whether physical, emotional, or environmental, your adrenal glands release cortisol, often called the “stress hormone.” Short-term cortisol is protective and helps you respond to challenges. However, chronic stress keeps cortisol elevated, which can disrupt digestion and overall gut health.

High cortisol can influence gut motility, speeding it up for some people, or slowing it down for others. (See our previous blog on Gut Motility here.)  It can also reduce digestive enzyme production, making it harder to break down and absorb nutrients efficiently. Over time, this may contribute to bloating, discomfort, and nutrient deficiencies. 

Chronic stress can also alter the gut microbiome, reducing beneficial bacteria and allowing harmful species to flourish. This imbalance, known as dysbiosis, can contribute to gas, irregular bowel movements, and inflammation. (More on this in our next blog in the series!) Prolonged stress may even increase intestinal permeability, sometimes called “leaky gut,” allowing undigested particles and toxins to enter the bloodstream and trigger further inflammation. [4]

Because stress plays such a key role, strategies that reduce stress during digestion can support gut health. One evidence-backed approach is mindful eating. By slowing down, paying attention to your food, and noticing how your body feels, you help the digestive system work more efficiently and may improve signaling along the gut-brain axis. Mindful eating can help reduce stress-related digestive disturbances and empower the rest and digest mode. [5]

Fun Fact: Although neurotransmitters are often associated with the brain, approximately 95% of the body’s serotonin is produced in the gut. While it doesn’t cross into the brain directly, it influences mood indirectly by signaling through the vagus nerve and affecting inflammation. This is another reason why gut health and mental wellbeing are so closely connected.[6]

Practical Strategies for a Healthy Gut-Brain Connection

Supporting the communication between your gut and brain doesn’t have to be complicated. Here are some practical strategies to strengthen this two-way connection and support both digestion and stress resilience:

Stimulate the Vagus Nerve

• Acts as the “traffic controller” for the gut-brain highway.
• Gentle practices like slow, deep breathing, meditation, cold exposure, singing, laughing, and humming can help improve vagal tone.
• OSEA offers a vagus nerve-focused line designed to support relaxation and nervous system balance through soothing aromatherapy.

Mindful Eating

• Slow down and pay attention to your meals, ideally without judgement.
• Notice flavors, textures, and fullness cues to reduce stress-related digestive disturbances.
• Supports the gut-brain axis and helps digestion function more efficiently.

Stress Management

• Daily practices such as journaling, breathwork, or short relaxation breaks can lower chronic cortisol levels.
• Gentle movement such as yoga, walking, or light strength training or great for stress resilience.
• Supplementation can naturally support stress response and help your body handle ongoing stressors.

Understanding the connection between your brain and gut highlights the importance of self-care as a cornerstone of whole-body health. When we consider all the traffic on the gut-brain highway, it becomes clear that we can set our own “rules of the road” to support digestion, stress resilience, and overall wellbeing.