Have you ever experienced a pit in your stomach right before a big interview or when walking into a room full of strangers? Having “gut feelings” is more than a catch phrase about intuition; it's a biological mechanism that can influence decision-making and action.

These internal feelings are your body’s physical response to your gut and brain communicating through the gut-brain axis. From stress and mental health disorders to digestive issues and gut dysbiosis, the gut and brain influence each other in many ways.

The Gut-Brain Axis

The brain talks to all of your body using nerves, a.k.a, the nervous system, but it talks the most to the g ut. This communication line has been vital for survival–from hunger cues and digestion monitoring to mood regulation and immuni ty.

And it’s not a one-way highway; the brain and the gut are sending messages freely back and forth to one another using the vagus nerve.

The Vagus Nerve

The parasympathetic nervous system, commonly referred to as the “rest and digest” response, is the opposite of the sympathetic nervous system, or “fight or flight.” Vagal nerves are a part of the parasympathetic nervous system that help control specific involuntary body functions like digestion, heart rate, and the immune system.

The vagus nerve is your body’s secret weapon for controlling your reaction to stress! When your body feels threatened, it increases cortisol to go into survival mode: increasing heart rate, dilating pupils, and slowing digestion.

Being in “fight or flight” mode and being chronically stressed can wreak havoc on our gut microbiome composition, leading to sluggish digestion and bloating, while affecting emotional well-being.

One of the main ways to stimulate the vagus nerve and tell the brain and body that everything is safe is through breathwork. Through controlled breathing, the body can slow heart rate, resume digestion, and calm an overstimulated mind.

How the Gut and Brain Influence One Another

Hormones and neurotransmitters are ways the gut talks with the brain and vice versa. Have you heard that serotonin, a main neurotransmitter that supports mood, sleep, digestion, wound healing, and bone health, is predominantly found in the cells lining the gut? Approximately 90% is found in the gastrointestinal tract, while only about 10% is actually produced in the brain!

Our gut microbiome is home to trillions of microorganisms that are unique to us; they’re affected by our diet, environmental exposures, stress, and even mood. When we have a diet filled with processed foods and high in sugar, experience chronic stress, and are exposed to toxins, the “good” bacteria in our microbiome become depleted. This affects the ecosystem in the microbiota, allowing more " bad " bacteria to harbor.

A gut that is under stress can make it difficult for the “feel good” chemicals, like serotonin and dopamine, to be released. This can lead to symptoms of anxiety, depression, and other mental health disorders. Another example of physical sensations of the brain and gut connection is losing an appetite when stressed or anxious.

To read more about the gut microbiome, check out my previous blogs, “Probiotics and Prebiotics: What You Need to Know” and “How Does Sugar Impact Your Brain, Gut Microbiome, and Immune System?”

Mental Stress Leading to a Stressed Microbiome

According to the American Institute of Stress, below are some signs the gut microbiome is affected by stress:

Bloating and gas
Diarrhea or constipation
- To read more about constipation, read my previous blog, “Are You Really Constipated? Signs, Root Causes & How to Get Things Moving Naturally.”
Acid reflux
Food intolerances
Low energy
Brain fog

The relationship between the gut microbiome and mental health has been a more researched topic as researchers continue to learn more about the effects our digestive system can have on the entire body. Experts have reported a link between patients with psychiatric disorders like depression, anxiety, bipolar disorder, schizophrenia, and autism spectrum disorder and having gut dysbiosis.

Master Your Microbiome

The ways the gut and brain communicate can be confusing, but learning more about your gut microbiome shouldn’t be. In my Master Your Microbiome program, I work 1-on-1 with you to test your microbiome and create a personalized gut health protocol.

Using the GI-MAP test, we’re able to examine the ecosystem of “good” and “bad” bacteria, digestive enzyme output, yeast and parasites, inflammation, gluten sensitivity, and more. As you learn more about your unique body through testing and a personal protocol, you’re able to give it the tools it needs to help your mind and body thrive.