Leaky Gut: What It Means & Why It Might Be Affecting Your Health
Leaky gut - it’s a term you may have heard, and one that often sparks confusion. “Do I have holes in my gut?” is a question I’m asked often in clinic. The short answer? Not exactly. But something important is happening in your body, and it’s worth understanding. The medical term is intestinal hyperpermeability, and it could be silently influencing symptoms you're dealing with every day, from bloating and fatigue to brain fog and low mood [1].
In this article, we’ll unpack what leaky gut is, how it connects to your immune system and brain, why it becomes more common with age, and how we can support your gut to heal naturally.
What Is Leaky Gut (Intestinal Hyperpermeability)?
Your gut lining is a dynamic, intelligent barrier. It allows beneficial nutrients and water through, while keeping bacteria, toxins, and undigested food molecules out [2]. But when this lining becomes too porous, larger particles can pass through into your bloodstream where they don’t belong. This can signal your immune system to respond to what it sees as a threat, contributing to low-grade, widespread inflammation [3].
Think of your gut lining like a flyscreen door. When it’s intact, fresh air flows through and pests stay out. But if the mesh tears, things get through that shouldn’t, and those intruders can set off alarm bells for your immune system.
The Role of Zonulin in Leaky Gut
Scientists have identified a protein called zonulin, which acts as a gatekeeper between your gut cells. It controls how tightly those cells are bound together. When zonulin levels rise, triggered by factors like gluten, stress, or certain microbes the junctions loosen, and the barrier becomes more permeable [19]. While this mechanism helps defend against acute infection, chronically elevated zonulin has been associated with increased intestinal permeability and may play a role in autoimmunity and inflammation.
Why Your Gut Barrier Matters
Your gut isn’t just a digestive organ it’s also one of your primary immune defence systems. It influences brain function, skin health, hormone balance, and metabolic resilience. When the gut barrier is weakened, you may experience symptoms that don’t initially seem digestive in nature like fatigue, irritability, cognitive fog, or skin flares [4].
Common Signs of Leaky Gut
Bloating or discomfort after meals
Fatigue or low energy
Brain fog or trouble concentrating
Cognitive decline or memory changes
Increasing food sensitivities
Skin issues like eczema, acne, or rashes
Aches and joint pain
Digestive issues like reflux, constipation, or loose stools
Mood swings or low mood
Even a few of these symptoms may indicate the need for a gut health review.
The Long-Term Health Impact of Leaky Gut
While we avoid disease-based claims in natural medicine, emerging research shows that intestinal hyperpermeability is associated with a range of health conditions that involve inflammation, immune dysregulation, or gut-brain disruption [5-7]. These may include:
Autoimmune responses
Neuroinflammation and cognitive decline
Blood sugar imbalance
Skin and joint inflammation
Reduced resilience and chronic fatigue
For clients over 50, gut health becomes increasingly important for healthy ageing and longevity [8].
Leaky Gut, Brain Health, and Healthy Ageing
As we age, our gut environment changes. A weakened gut barrier can allow bacterial components like lipopolysaccharides (LPS), inflammatory molecules from the outer membrane of certain bacteria, to enter the bloodstream. LPS can activate the immune system and promote neuroinflammation (brain inflammation), which has been linked to cognitive decline and metabolic dysfunction [14]. Research also shows a link between high LPS and insulin resistance, abdominal weight gain, diabetes and inflammation [15, 16].
Protecting your gut lining may support clearer thinking, better blood sugar balance, and more graceful ageing. That’s why we recommend gut health reviews for all clients 50 and over.
Why Leaky Gut Becomes More Common with Age
From your 40s onward, natural shifts in gut function begin. You produce less stomach acid and fewer enzymes, the gut lining becomes thinner, and beneficial gut bacteria may decline [9]. These changes can make your gut more vulnerable to stress, food triggers, and microbial imbalances.
What Causes Leaky Gut?
There’s rarely one single cause. Most cases involve a mix of lifestyle and environmental stressors, including:
Processed diet: Low-fibre, high-sugar diets affect gut lining integrity [10]
Chronic stress: Psychological stress alters brain-gut signalling and affects mucosal health [11]
Antibiotic exposure: Repeated or broad-spectrum antibiotics can disturb microbiome diversity and gut resilience [17]
PPI medications: Long-term acid-suppressing medication may impair digestion and promote bacterial overgrowth [18]
NSAIDs: Non-steroidal anti-inflammatory drugs (like ibuprofen) are known to increase gut permeability
Environmental toxins and alcohol: Can irritate the gut lining and impair repair capacity
Your Microbiome Is Your Gatekeeper
Your gut bacteria play a direct role in maintaining your intestinal lining. They produce butyrate and other short-chain fatty acids that fuel the gut wall, regulate immune function, and keep inflammation in check [12]. When microbial diversity is reduced, or when opportunistic microbes overgrow (called dysbiosis), the gut barrier suffers. That’s why microbiome testing is often paired with intestinal permeability testing in clinical care.
Can Leaky Gut Cause Allergies or Sensitivities?
It may play a role. When larger food molecules slip into the bloodstream, your immune system may begin to react, interpreting them as foreign invaders. This can appear as new or worsening food intolerances, histamine sensitivity, or immune irritation [13]. Supporting the gut lining is one of the most effective long-term strategies for improving tolerance and reducing reactivity.
How Do You Know If You Have Leaky Gut?
The most accurate way to assess intestinal permeability is through targeted substrate testing, considered the gold standard in gut integrity analysis. In our clinic, we utilise this advanced, non-invasive testing to evaluate how effectively your gut barrier is functioning. It provides meaningful clinical insights to help determine whether intestinal permeability may be contributing to your symptoms.
This test is available by referral for existing clients:
As part of an Initial or Review Consultation
Included in your Annual Wellness Review, especially recommended from age 50+
Can the Gut Heal? Absolutely.
Your intestinal lining is designed to regenerate, but only when the right foundations are in place. Together, we can tailor a gut healing protocol that reduces triggers, restores microbial balance, and nourishes your barrier lining. Supporting gut integrity can improve energy, digestion, clarity, immune function, and even sleep, outcomes that often extend far beyond the gut itself.
Take the Next Step for Your Gut Health
If you’ve been dealing with vague or persistent symptoms and suspect your gut may be involved, let’s assess it properly. Gut barrier testing offers clear, actionable insights that help us develop a personalised plan for healing.
New to the clinic?
Book your Initial Consultation
Already a client?
Schedule your Annual Review
Explore our E Courses on Gut Health
Written by Kylie Cloney BHSc. Complementary Medicine, Adv. Dip Nutr. Medicine
Wellness for Life – Your Plan, Grounded in Science, Guided by Nature.
References
Fasano A. Intestinal permeability and its regulation by zonulin: diagnostic and therapeutic implications. Clin Gastroenterol Hepatol. 2012;10(10):1096-1100.
Turner JR. Intestinal mucosal barrier function in health and disease. Nat Rev Immunol. 2009;9(11):799-809.
Bischoff SC, Barbara G, Buurman W, et al. Intestinal permeability-a new target for disease prevention and therapy. BMC Gastroenterol. 2014;14:189.
de Punder K, Pruimboom L. Stress induces endotoxemia and low-grade inflammation by increasing barrier permeability. Front Immunol. 2015;6:223.
Man AL, Bertelli E, Rentini S, et al. Age-associated modifications of intestinal permeability and innate immunity. Ageing Res Rev. 2014;17:34-45.
Arrieta MC, Bistritz L, Meddings JB. The intestinal barrier and its role in immune homeostasis. Nat Rev Gastroenterol Hepatol. 2006;3(9):475-481.
Zhang C, Li S, Yang L, et al. Structural modulation of gut microbiota in life-long calorie-restricted mice. Nat Commun. 2013;4:2163.
Odamaki T, Kato K, Sugahara H, et al. Age-related changes in gut microbiota composition from newborn to centenarian. Gastroenterology. 2016;150(4):995–1007.
Ghosh S, Whitley CS, Haribabu B, Jala VR. Diet microbiome interactions and their implications for healthy living. Nutrients. 2020;12(1):223.
Rapin JR, Wiernsperger N. Possible links between intestinal permeability and food processing: a potential therapeutic niche for glutamine. Clin Nutr. 2010;29(6):717-721.
Konturek PC, Brzozowski T, Konturek SJ. Stress and the gut: pathophysiology, clinical consequences, diagnostic approach and treatment options. J Physiol Pharmacol. 2011;62(6):591-599.
Louis P, Flint HJ. Formation of propionate and butyrate by the human colonic microbiota. Environ Microbiol. 2017;19(1):29-41.
Fasano A. Zonulin, regulation of tight junctions, and autoimmune diseases. Ann N Y Acad Sci. 2012;1258(1):25-33.
Zhu B, Wang X, Li L. Human gut microbiome: the second genome of human body. Protein Cell. 2010;1(8):718-725.
Cani PD, Bibiloni R, Knauf C, et al. Changes in gut microbiota control metabolic endotoxemia-induced inflammation in high-fat diet induced obesity and diabetes in mice. Diabetes. 2008;57(6):1470-1481.
Cani PD, Amar J, Iglesias MA, et al. Metabolic endotoxemia initiates obesity and insulin resistance. Diabetes. 2007;56(7):1761-1772.
Becattini S, Taur Y, Pamer EG. How the gut microbiota impacts antibiotic efficacy. Trends Microbiol. 2016;24(6):478-490.
Freedberg DE, Toussaint NC, Chen SP, et al. Proton pump inhibitors alter specific taxa in the human gastrointestinal microbiome: a crossover trial. Gastroenterology. 2015;149(4):883-885.e9.
Fasano A. Zonulin and its regulation of intestinal barrier function: The biological door to inflammation, autoimmunity, and cancer. Physiol Rev. 2011;91(1):151-175.
Disclaimer:
This post is for general education only and is not medical advice. Please consult your healthcare professional. See our Medical Disclaimer.