Understanding Leaky Gut: Symptoms, Causes, and How to Heal Your Gut

As someone who is passionate about gut health, I often see clients struggling with digestive issues that impact their overall wellbeing. In this article, I'll dive into "leaky gut", a term that's gained attention but is often misunderstood. In this article, we'll explore what it means, common symptoms, potential causes, and practical, nutrition-focused strategies to support gut healing. My goal is to empower you with knowledge so you can make informed choices about your health. If this resonates, get in touch as I love to create personalised nutrition plans, to help my clients feel their absolute best.

What Is Leaky Gut?

Leaky gut, also known as increased intestinal permeability, refers to a condition where the lining of the intestines becomes more porous than normal, allowing substances such as bacteria, toxins, and undigested food particles to pass into the bloodstream (Camilleri, 2019). The intestinal barrier is a complex system consisting of a mucus layer, epithelial cells connected by tight junctions (proteins such as zonula occludens-1, occludin, and claudins), and immune defences. When this barrier is compromised, it can lead to systemic inflammation and is associated with various health issues, though it's not yet recognised as a formal medical diagnosis in many circles (Lacy et al., 2024). Importantly, while folklore links leaky gut to a wide range of problems, scientific evidence primarily ties it to gastrointestinal disorders such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), as well as extra-intestinal conditions such as autoimmune diseases and metabolic disorders (Mu et al., 2017).

It's worth noting that increased permeability can be an epiphenomenon, meaning it's a byproduct of other issues rather than the root cause, and restoring barrier function alone may not cure underlying diseases (Camilleri, 2019). As a nutritionist, I view it as a signal that the gut ecosystem needs attention, often through diet and lifestyle adjustments.

Symptoms of Leaky Gut

Symptoms attributed to leaky gut are often nonspecific and overlap with other conditions, making diagnosis challenging. Common signs include bloating, gas, abdominal cramps, fatigue, food sensitivities or allergies, headaches, and joint pain (Camilleri, 2019). In more severe cases, it may contribute to chronic inflammation, leading to issues such as skin conditions, mood disorders (e.g., anxiety or depression), and autoimmune symptoms (Aleman et al., 2023). For instance, elevated levels of zonulin, a protein that regulates tight junctions, have been linked to increased permeability and symptoms in conditions such as IBS, where patients report diarrhea, abdominal pain, and altered bowel habits (Di Vincenzo et al., 2023).

From my practice, clients often describe persistent digestive discomfort that doesn't resolve with over-the-counter remedies. If you're experiencing these, it's essential to consult a healthcare professional to rule out other causes, as no validated test currently exists for diagnosing leaky gut syndrome directly (Lacy et al., 2024).

What Causes Gut Permeability?

Several factors can disrupt the intestinal barrier, leading to increased permeability. Diet plays a central role: high-fat diets (especially saturated fats), refined sugars, and processed foods can induce gut dysbiosis, which is an imbalance in the gut microbiome, whereby beneficial and keystone bacteria  e.g., Lactobacillus and Bifidobacterium are reduced, promoting the overgrowth of harmful ones (Chae et al., 2024). This dysbiosis decreases short-chain fatty acid (SCFA) production, which is crucial for maintaining tight junction integrity, and increases proinflammatory cytokines such as TNF-α and IL-6 (Aleman et al., 2023).

Other causes include:

Medications and substances: Nonsteroidal anti-inflammatory drugs (NSAIDs) and alcohol damage epithelial cells and alter tight junctions, increasing permeability (Camilleri, 2021).

Stress and lifestyle: Psychological stress, intense exercise, and sleep disruptions can activate pathways that loosen tight junctions (Camilleri, 2019).

Infections and inflammation: Bacterial infections, dysbiosis, or chronic conditions like IBD can degrade the mucus layer and promote bacterial translocation (Di Vincenzo et al., 2023).

Ageing and genetics: As we age, the barrier naturally weakens, and genetic predispositions can also make some individuals more susceptible (Escalante et al., 2024).

Emulsifiers in processed foods (e.g., carboxymethylcellulose) and artificial sweeteners also thin the mucus layer, exacerbating the issue (Camilleri, 2021). In essence, modern Western diets low in fibre and high in additives are key culprits, highlighting the need for nutritional intervention.

How You Can Heal Your Gut

Healing leaky gut focuses on restoring barrier integrity through evidence-based nutrition and lifestyle changes. While more human trials are needed, promising strategies include avoiding triggers and incorporating supportive foods and supplements (Camilleri, 2021). As a nutritionist, I recommend starting with a personalised assessment, but here are some general evidenced based tips:

Dietary Changes

Avoid harmful foods: Limit high-fat, high-sugar, and processed items, alcohol, and emulsifiers to reduce inflammation and dysbiosis (Chae et al., 2024). A low-FODMAP diet may help in IBS cases by minimising fermentation that stresses the gut barrier (Aleman et al., 2023).

Increase fibre and prebiotics: Foods rich in inulin such as vegetables (e.g., onions, garlic) boost SCFAs production, which enhance tight junctions. Studies show inulin reduces zonulin and permeability in healthy individuals (Camilleri, 2021).

Incorporate fermented foods: Yoghurt, kefir, kombucha and sauerkraut provide probiotics that upregulate tight junction proteins such as ZO-1 and occludin (Aleman et al., 2023).

Supplements

Based on human studies:

Probiotics: Strains including Lactobacillus rhamnosus GG and Bifidobacterium infantis improve barrier function and reduce symptoms in IBS and obesity (Aleman et al., 2023).

Glutamine: This amino acid supports epithelial repair and normalises permeability in post-infectious IBS (Camilleri, 2021).

Vitamin D and zinc: Vitamin D reduces permeability in Crohn's disease, while zinc carnosine stabilises the gut lining post-NSAID use (Camilleri, 2019).

Polyphenols: Found in berries and green tea, enhance tight junctions and reduce inflammation (Camilleri, 2021).

Lifestyle Tips

Regular exercise, such a daily walks, strengthens the digestive system, and stress management (e.g., mindfulness, meditation, yoga, breathwork) can prevent flare-ups (Camilleri, 2019). Aim for 30+ grams of fibre daily and stay hydrated.

Healing takes time, it’s the long game. It often takes many weeks to months, but consistent changes can lead to noticeable improvements. If you'd like guidance personalised to your needs, book a consultation with me here.

References

Aleman, R. S., Moncada, M., & Aryana, K. J. (2023). Leaky gut and the ingredients that help treat it: A review. Molecules, 28(2), 619. https://doi.org/10.3390/molecules28020619

Camilleri, M. (2019). Leaky gut: Mechanisms, measurement and clinical implications in humans. Gut, 68(8), 1516–1526. https://doi.org/10.1136/gutjnl-2019-318427

Camilleri, M. (2021). What to do about the leaky gut. Mayo Clinic Proceedings, 96(10), 2721–2733. https://doi.org/10.1016/j.mayocp.2021.05.027

Chae, Y. R., Lee, S. H., Nam, G. H., Yang, J. B., & Ryu, J. H. (2024). Diet-induced gut dysbiosis and leaky gut syndrome. Journal of Microbiology and Biotechnology, 34(4), 747–756. https://doi.org/10.4014/jmb.2312.12031

Di Vincenzo, F., Del Gaudio, A., Petito, V., Lopetuso, L. R., & Scaldaferri, F. (2023). Gut microbiota, intestinal permeability, and systemic inflammation: A narrative review. Internal and Emergency Medicine, 19(2), 275–293. https://doi.org/10.1007/s11739-023-03374-w

Escalante, J., & Camilleri, M. (2024). Leaky gut in systemic inflammation: Exploring the link between gastrointestinal disorders and age-related diseases. Inflammatory Bowel Diseases, 30(Supplement_1), S32–S40. https://doi.org/10.1093/ibd/izad284

Lacy, B. E., & Mearin, F. (2024). Leaky gut syndrome: Myths and management. Gastroenterology, 166(6), 1031–1042. https://doi.org/10.1053/j.gastro.2024.02.035

Mu, Q., Kirby, J., Reilly, C. M., & Luo, X. M. (2017). Leaky gut as a danger signal for autoimmune diseases. Frontiers in Immunology, 8, 598. https://doi.org/10.3389/fimmu.2017.00598