Leaky Gut (Intestinal Permeability): What It Is and How to Heal It
Intestinal permeability, commonly called "leaky gut," has moved from alternative medicine fringe to mainstream gastroenterology research. The peer-reviewed evidence now clearly supports its existence and its role in driving systemic inflammation, autoimmunity, gut dysfunction, and neurological symptoms.
What Is Intestinal Permeability?
The gut lining is a single cell layer thick, maintained by tight junction proteins that control what passes from the gut into the bloodstream. When tight junctions are disrupted, the barrier becomes permeable, allowing bacterial fragments (lipopolysaccharides), undigested food particles, and microbial metabolites to enter circulation [1].
This triggers a systemic immune response. The immune system mounts an inflammatory reaction to these "foreign" particles, which can become chronic. This chronic low-grade inflammation is increasingly recognised as a driver of conditions ranging from autoimmunity to depression to hormonal dysfunction.
What Causes Leaky Gut?
• Dysbiosis and gut microbial imbalance (see gut-brain axis)
• SIBO (small intestinal bacterial overgrowth)
• Chronic stress and elevated cortisol (directly disrupts tight junctions)
• NSAID overuse (ibuprofen, aspirin)
• Alcohol
• Ultra-processed food diet
• Gluten in susceptible individuals (zonulin, the tight junction regulator, is upregulated by gluten exposure)
• Chronic infections
• Autoimmune conditions
Nutritional Protocol for Healing Intestinal Permeability
Remove Triggers
Eliminating dietary and lifestyle triggers is the first step: reducing alcohol, NSAIDs, ultra-processed foods, and trialling a 4-6 week gluten elimination in susceptible individuals.
Repair the Gut Lining
• L-glutamine: the primary fuel for enterocytes (gut lining cells). 5 to 10g daily on an empty stomach supports mucosal repair
• Zinc carnosine: directly supports gut mucosal integrity and reduces inflammation at the gut wall [2]
• Vitamin A: essential for mucosal cell differentiation and immune barrier function
• Collagen and glycine (from bone broth or supplementation): provide structural support for the gut lining
Restore the Microbiome
A diverse, fibre-rich diet restores beneficial bacterial populations that support tight junction integrity. Specific strains including Lactobacillus rhamnosus GG and Bifidobacterium species have demonstrated efficacy in reducing intestinal permeability in clinical trials.
Reduce Gut Inflammation
Omega-3 fatty acids, polyphenols, curcumin, and reducing dietary inflammatory triggers (seed oils, refined sugar) all reduce gut wall inflammation and support barrier repair.
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References
• Fasano A. Leaky gut and autoimmune diseases. Clinical Reviews in Allergy and Immunology. 2012;42(1):71-78. PubMed
• Mahmood A, et al. Zinc carnosine, a health food supplement that stabilises small bowel integrity and stimulates gut repair processes. Gut. 2007;56(2):168-175. PubMed
