IBS & Stress: The Gut-Brain Connection You Need to Understand

IBS—irritable bowel syndrome—is one of the most common yet misunderstood digestive issues affecting millions of people worldwide. In this eye-opening episode of The Tonic, host Jamie Bussin welcomes back naturopathic doctor Colleen Hartwick to explore the real causes of IBS and what you can do about it—starting today.

IBS is no longer a mystery illness. Once referred to by names like “mucous colitis,” IBS is now understood to be a complex gut-brain axis disorder. She also refers to its recognition in the Merck Manual, the diagnostic tool used by the medical profession, as being updated as a disorder of the gut-brain axis. Dr. Hartwick explains how the body’s nervous system—especially the vagus nerve—plays a pivotal role in either calming digestion or triggering symptoms. When you're stressed, the body flips into “fight or flight” mode, shutting down digestion, disrupting enzyme production, and triggering constipation, diarrhea, gas, and bloating. The body prioritizes survival over digestion when exposed to stress, which leads to many of these symptoms.

But what actually causes IBS flare-ups? According to Dr. Hartwick, common culprits include:

• Dietary triggers like dairy, gluten, and high-FODMAP foods (e.g., onions, garlic, apples).
• Artificial sweeteners including aspartame and sucralose, which disrupt gut bacteria, and the microbiome.
• Hormonal shifts (especially in women during menstruation).
• Sleep deprivation and dehydration, which amplify gut sensitivity.

Listeners will learn practical tips to take control of IBS symptoms. Dr. Hartwick suggests starting with a food and symptom journal, noting bowel movements, stress levels, sleep patterns, and diet to uncover individual triggers. This simple, personalized approach empowers people to identify patterns and reclaim control of their gut health. This can help determine “cause and effect” trends in gut health.

She also covers natural remedies for IBS, including:

• Magnesium Bisglycinate: Ideal for stress-related IBS and better sleep.
• Magnesium Citrate: A gentle, natural support for constipation relief, she also discusses the role of soluble fibre and adequate hydration.
• L-Theanine: A calming amino acid that boosts GABA levels in the brain, an excellent option for stress related IBS.
• L-Glutamine: Essential for healing a leaky or inflamed gut, especially after diarrhea.
• Probiotics: Focused on diverse strains featuring Lactobacillus and Bifidobacterium to support microbiome balance.
• Digestive enzymes and bitters to enhance food breakdown and reduce bloating.

The podcast also dives into lifestyle interventions which can help regulate the nervous system and ease IBS symptoms, such as:

• Creating a consistent daily routine (sleep, meals, activity).
• Practicing mindfulness and breathing to mange stress.
• Identifying de-stress rituals—from walking to rock climbing—that keep you in the moment. Avoid stressing about the future or ruminating about the past.
• Staying hydrated to support motility and stool formation.

This conversation goes beyond surface-level solutions. It’s a deeply informed, science-based look at how IBS is connected to your emotions, habits, hormones, and gut microbiome—and what you can do holistically to feel better.

Whether you're newly diagnosed, dealing with unexplained digestive issues, or searching for natural solutions that work, this episode is a must-listen. Dr. Hartwick’s insights are clear, compassionate, informative, and grounded in naturopathic clinical experience.

🩺 Listen now to learn how understanding your nervous system, nutrition, and natural health can be the key to lasting digestive comfort.