Episode 115: Why Your Gut Is Running Your Immune System (And What to Do When It’s Not Working)
Your gut isn’t just digesting food, it’s directing your immune system. Around 70% of your immune cells live in the gut, and when that relationship becomes disrupted, the consequences ripple far beyond digestion. In this episode, we break down the gut-immune axis and explain why symptoms like fatigue, brain fog, recurrent infections, skin flare-ups, IBS, and autoimmune disease often trace back to gut dysfunction.
You’ll learn what increased intestinal permeability (often called leaky gut) actually means, how microbiome imbalance drives chronic inflammation, and why conventional testing frequently misses this connection. We also explore the six most common disruptors damaging immune function today: chronic stress, antibiotics, ultra-processed food, poor sleep, alcohol, and NSAIDs, and how they quietly alter gut integrity over time.
This episode answers questions like:
“How does the gut affect the immune system?”
“What causes leaky gut?”
“Can gut health cause autoimmune disease?”
“How does cortisol affect gut health?”
“Do antibiotics weaken the immune system?”
“How long does it take to rebuild gut after antibiotics?”
“How to repair gut lining naturally”
Most importantly, this episode gives you a practical framework for action and explains how to restore gut health and immune balance in a sustainable, clinically grounded way. This episode also includes an invitation to the Goode Health Studio.
DISCLAIMER: The content in this podcast and related website is not intended to be a substitute for medical advice. It is not intended to be used to diagnose or treat, instead it is designed to help educate and inspire. Always seek the advice of a professional medical practitioner or qualified health practitioner. Never ignore or disregard advice given to you based on information in this podcast or related website and do not delay in seeking medical advice.
Timestamps:
[03:15] - What Is the Gut-Immune Axis?
70% of Your Immune System Lives in Your Gut. Understand gut-associated lymphoid tissue (GALT), immune training, and how the microbiome calibrates immune response.
[05:00] - The Gut Barrier & Increased Intestinal Permeability (“Leaky Gut”)
How a one-cell-thick intestinal lining regulates immune activation, and what happens when gut permeability increases.
[06:50] - The 6 Biggest Gut-Immune Disruptors
Chronic stress (cortisol), antibiotics and microbiome damage, ultra-processed foods, poor sleep, alcohol, and NSAIDs.
[10:40] - How Stress, Sleep & the Microbiome Create a Vicious Cycle
The gut-brain-immune connection and how cortisol suppresses secretory IgA and damages gut integrity.
[12:40] - Signs Your Gut-Immune Axis Is Under Stress
Recurrent illness, slow recovery, autoimmune flares, IBS, bloating, food sensitivities, eczema, acne, fatigue and brain fog.
[14:30] - Why Fatigue, Brain Fog & Low Mood Can Be Immune-Driven
How chronic low-grade inflammation and immune activation drain energy and affect neurological function.
[15:40] - The Functional Medicine 4R Protocol for Gut Repair
Remove, Replace, Re-inoculate, Repair. The clinical framework to restore gut health and immune balance.
[18:30] - Key Nutrients for Gut Lining Repair & Immune Regulation
L-glutamine, zinc carnosine, omega-3 fatty acids, vitamin D, collagen support and microbiome diversity.
[19:45] - Why You Can’t Heal the Gut Without Addressing Chronic Stress
The adrenal–gut–immune connection and why stress physiology must be stabilised for lasting immune health.
“Your gut lining is one cell thick. One cell separating everything you eat, every bacteria, every toxin, from your bloodstream. When that barrier is intact, your immune system stays calm.
But when that barrier becomes more permeable, what we often call ‘leaky gut’, partially digested food particles and bacterial toxins cross into circulation. And your immune system does what it was designed to do: it reacts.
Not because it’s broken. But because it’s responding to a threat coming from inside the house.”
Essential learnings from this episode…
The gut isn’t just for digestion, it houses the majority of immune cells and “trains” them to distinguish between threats and harmless substances. A healthy microbiome is essential for balanced immune function.
Increased intestinal permeability allows food particles and bacterial toxins into the bloodstream, triggering ongoing immune activation. This low-grade inflammation can contribute to fatigue, skin conditions and autoimmune disease.
Chronic stress directly damages gut integrity. Elevated cortisol increases gut permeability, suppresses secretory IgA and disrupts the microbiome. Stress is one of the most common root causes of gut-immune dysregulation.
Repeated antibiotic use, processed diets, alcohol and regular NSAID use can significantly alter gut bacteria and impair immune regulation — even without obvious digestive symptoms.
A chronically activated immune system is metabolically expensive. Many people experience exhaustion, poor concentration and low mood as downstream effects of gut-driven inflammation.
Functional medicine addresses gut-immune dysfunction through Remove, Replace, Re-inoculate and Repair, combining dietary changes, microbiome restoration, gut lining support and stress regulation.
EPISODE 115
Important links & mentions from this episode
The Optimal You 7 Day Reset (£7.99)
Goode Health Clinic Functional Medicine Packages
Take the FREE MitoImmune Health Assessment
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