The Gut-Brain Connection, Explained by a Dietitian

Ever get butterflies in your stomach before a big event? Or feel your stomach flip when you're stressed? That’s not just in your head. It’s your gut and brain talking to each another.

The gut-brain connection isn’t just a wellness trend or some woo-woo science. There’s solid research showing that what happens in your gut directly impacts your brain (and vice versa).

Let’s break down how your gut works, what the microbiome does, the science behind the gut-brain connection, and real-world ways to strengthen it.

Photo by Faruk Tokluoğlu on Unsplash

Meet Your Microbiome

Quick anatomy refresher: your “gut” isn’t just your stomach. It’s your entire digestive tract, a 30-foot-long, twisty-turny tube running from your mouth to your anus.

The colon (AKA your large intestine) is home to most of the trillions of bacteria in your gut. These bacteria, plus viruses and fungi, make up your gut microbiota. And these microbes aren’t just hanging out. They’re involved with:

• Vitamin Production — Your gut bacteria are like tiny supplement factories, cranking out B vitamins and vitamin K (key for blood clotting).

• Hormone Help — They help produce and maintain hormone levels. Think: recycling estrogen and regulating hunger hormones (like GLP-1, the “I’m full” hormone that weight-loss medications like Ozempic target).

• Mood Regulation — Your gut bacteria produce neurotransmitters (chemicals that shape your mood), including 95% of your serotonin, the "feel-good" hormone. Your gut also helps manage levels of dopamine (motivation) and GABA (relaxation).

Think of the gut microbiota like a rainforest. In a healthy rainforest, all the plants, animals, and insects live in balance, keeping the ecosystem strong. Your gut works the same way: the more diverse, balanced, and pathogen-free, the healthier the gut.

Photo by Eutah Mizushima on Unsplash

The Gut-Brain Connection: Where Microbes Meet the Mind

The central nervous system (CNS) is the body's command center — made up of the brain and spinal cord. Your brain has 12 cranial nerves, one of which connects directly to the gut: the vagus nerve.

The vagus nerve is the main communication hotline between the gut and the brain. Nervous before a big date? Stomach doing flips? That’s your gut-brain axis in action: a two-way conversation traveling along the vagus nerve.

But it doesn’t stop there.

Because the gut is so complex (made up of 10+ separate parts) it has its own nervous system called the enteric nervous system (ENS). Nicknamed the “second brain,” the ENS is embedded in your gut and contains over 100 million neurons (more than your spinal cord!).

If the CNS is the federal government, the ENS is your state government, managing local operations. For example, the ENS can initiate peristalsis (rhythmic muscle contractions that move food through your digestive tract) on its own, without input from the brain.

💡 Quick trivia: Vagus means “wandering” in Latin. Fitting, since this nerve wanders from your brainstem all the way to your gut, hitting your heart, lungs, and more along the way. It regulates digestion, heart rate, breathing, swallowing, and even speech.

How to Strengthen Your Gut-Brain Connection

Your gut and brain are constantly chatting, but like any relationship, the connection can weaken if you don’t nurture it. Here’s how to strengthen your gut-brain connection through the vagus nerve (CNS – think: federal government) and gut health (ENS – think: state government).

Vagus Nerve Support

When the vagus nerve is weak or under-stimulated, that’s when digestive trouble shows up. The fix? Treat your vagus nerve like a muscle: train it. Here’s how:

• Cold Exposure – Try cold showers, ice baths, or splashing cold water on your face.

• Deep Breathing – Slow, diaphragmatic breathing helps switch your nervous system into “rest and digest” mode.

• Humming, Singing & Gargling – The vagus nerve runs through your vocal cords, so making noise—singing, chanting, or even gargling water—can help tone it.

• TruVaga – Devices like TruVaga directly stimulate the vagus nerve through non-invasive electrical pulses. 🤫 PS: Dietitian Driven has an in-house vagus nerve stimulator to try!

• Manage Stress – When you’re constantly stressed, your body stays stuck in fight-or-flight mode, not ideal for digestion!

Photo by Polina Kuzovkova on Unsplash

Gut Health Support

You’ve got to give your microbiome the right kind of TLC. That means feeding it, moving it, and letting it rest. Here’s how to show your gut some love:

• Fiber – Fiber is your gut bacteria’s favorite snack. Diverse, plant-based fiber (think whole grains, fruits, veggies) feeds bacteria, so they produce byproducts that protect your gut lining.

• Fermented Foods – Fermented foods like yogurt, kefir, kimchi, and sauerkraut introduce new beneficial bacteria to your gut.

• Sleep Better – Your gut bacteria follow a circadian rhythm, just like you. Poor sleep can throw them off balance, affecting digestion and mood.

• Exercise Regularly – Movement supports a diverse microbiome. Even a 30-minute walk a day can strengthen your gut-brain connection.

• Gut-Healing Foods – Omega-3s (found in salmon, flaxseeds, and walnuts) and polyphenols (from berries, dark chocolate, and green tea) support healthy gut bacteria.

The better you feed your gut, the stronger your gut-brain connection.

Photo by Laura Adai on Unsplash

The Bottom Line

Your gut and brain are in constant communication, and how well they get along affects everything from digestion to mood to long-term health.

If you’ve been struggling with brain fog, anxiety, or gut issues, focusing on this connection could be the missing piece.

Take care of your gut, and it’ll take care of your brain. And we’d love to work with you to nurture the gut-brain connection.