There's a reason we talk about "gut feelings" and "butterflies in your stomach." Your gut and your brain were formed from the same tissue during fetal development, and they remain in constant communication throughout your life. As a naturopathic doctor, I've always believed in looking at the whole person rather than just the symptoms — and the science is now confirming what this approach has long suggested.
Your Second Brain
Your gut has its own nervous system — it's called the Enteric Nervous System (ENS), and it contains roughly 100 million neurons lining your digestive tract from mouth to the end. These neurons have the same neurotransmitter receptors found in your brain, and they allow your gut to direct digestive processes largely on its own, independent of your central nervous system. The two systems communicate through the vagus nerve, which acts like a direct phone line between your gut and your brain.
Here's a striking detail: about 95% of your body's serotonin — the neurotransmitter most associated with mood, calm, and well-being — is produced in your gut, not your brain. Your gut also houses dopamine, norepinephrine, and even natural benzodiazepines. When the mucous lining of your digestive tract is inflamed or damaged, the health of these neurons is compromised, and with it, your emotional state. This is why digestive issues and mood disorders so often travel together.
What You Can Do
Improving the health of your gut can have a meaningful impact on how you feel — both physically and emotionally. Here's where to start:
- Shift towards a whole-food, plant-rich diet. A meta-analysis of 13 international studies found that people who followed a Mediterranean-style diet had lower rates of depression and cognitive decline compared to those eating a high-fat, high-sugar diet. Your gut flora changes based on what you eat — and healthier flora produces more beneficial neurotransmitters.
- Add a quality probiotic containing Lactobacillus and Bifidobacterium strains. Research has shown these specific bacteria can influence GABA levels in the brain, lower cortisol, and support the regulation of serotonin. Studies have also found that people consuming probiotic-rich diets showed reduced activity in brain areas that process emotions and physical sensations.
- Consider fish oils with a high EPA-to-DHA ratio. Omega-3 fatty acids reduce inflammation throughout the body and make it easier for serotonin to pass through cell membranes. Countries with high fish consumption consistently show lower rates of depression.
- If you experience ongoing digestive symptoms — bloating, gas, alternating constipation and diarrhea — you may have unidentified food sensitivities. Unlike allergies (IgE reactions), food sensitivities (IgG reactions) can be subtle and delayed, making them hard to identify without testing. We offer food sensitivity testing that can pinpoint which foods may be contributing to gut inflammation.
- Manage stress actively. Under stress, your body shifts blood away from digestion and into your limbs (the "fight or flight" response). This means food isn't broken down properly, which creates inflammation. Practices like mindfulness meditation, yoga, or even simple deep breathing help shift your nervous system back into the "rest and digest" state.
- Talk to your provider about targeted supplements: L-glutamine to support gut lining repair, magnesium for mental and physical tension, B vitamins (especially B6 and B12) for neurotransmitter production, and vitamin D, which has been shown to be a good predictor of depression risk.
Mood and digestion are deeply personal topics, and what works for one person may not work for another. Supplements like St. John's Wort act similarly to SSRIs by keeping more serotonin available in the brain — but they can interact with other medications. Always discuss options with your healthcare provider to find the right approach for you.
If you've been struggling with mood, energy, or digestive issues and feel like you're not getting answers, the gut-brain connection may be the missing piece. We can help you identify food sensitivities, assess your gut health, and build a plan that addresses both your physical and emotional well-being — because they're more connected than most people realize.