The gut epithelium is one of the body’s key defense systems. This layer of cells lining the intestines acts as a ‘gatekeeper’ between the digestive tract and the rest of the body, preventing harmful substances from entering the bloodstream.^[1]

The gut lining works by producing mucus, enzymes, and antimicrobial proteins that help defend against harmful microbes and toxins.

However, the integrity of the intestinal epithelium can be damaged by common factors such as stress, poor diet, antibiotics, excessive alcohol intake, and drugs. Each of these factors can trigger inflammatory processes that damage the gut cells and tight junctions, increasing permeability and allowing undigested food, toxins, and bacteria to enter the bloodstream. This condition is often referred to as ‘leaky gut’.^[2]

Damage to the intestinal barrier is associated with several health concerns, including dysbiosis, chronic inflammation, and/or an   (when the body’s immune system attacks its own cells). These issues may then contribute to inflammatory bowel disorders, heart diseases, obesity, type 1 diabetes mellitus, and celiac disease.^[3] Recent studies have also suggested a link to neurological diseases such as Parkinson’s.^[4]

 

Evidence-based indicators of gut dysfunction include:

• Digestive issues: Persistent bloating or gas, food intolerances or sensitivities; irregular bowel movements (constipation or diarrhoea)
• Immune dysfunction: Frequent illness or infections; skin conditions such as eczema, rosacea
• Neurological concerns: Brain fog; unexplained fatigue; low mood, irritability, mood swings

 

Natural ways to support healing of the gut barrier

The gut epithelium is one of the fastest-renewing tissues in the body. However, a few simple changes to your diet and lifestyle can speed the healing process and maintain its valuable function.

Diet

Eat more:

Fibre and prebiotic foods, such as inulin and fructooligosaccharides (FOS), are fermented by bacteria in the colon, which then produce short-chain fatty acids (SCFAs). SCFAs support the integrity of the intestinal epithelium by reducing inflammation and regulating immune responses.^[5]
Prebiotic foods include onions, garlic, leeks, asparagus, artichoke, and chicory.^[6]

Probiotic foods provide beneficial lactic acid bacteria and other microbes directly to the gut, where they can adhere to the gut epithelium and restore healthy balance.^[7] Good sources include unsweetened yoghurt, sauerkraut, kimchi, and kefir.

Omega-3 fatty acids. Increasing intake of omega-3 fatty acids is shown to improve intestinal barrier dysfunction almost as effectively as SCFAs.^[8]

 

Eat fewer:

Artificial sweeteners such as sucralose and aspartame can increase intestinal permeability by causing apoptosis (programmed cell death) in intestinal epithelial cells; even low intake can reduce the expression of claudin 3, a protein involved in forming tight junctions.^[9]

Emulsifiers, trans fats, and artificial additives – often used in processed sauces and snacks – can trigger inflammatory responses in the gut lining and reduce the thickness of the mucus layer, compromising its protective function against pathogens.^[10]

If you notice sensitivities to foods like gluten or dairy, avoiding them may help reduce gut irritation. A nutritionist can guide you through an elimination process.

 

Supplement support

Probiotics

Probiotic supplements help to reinforce the gut barrier by influencing genes and proteins that control tight junctions.^[11] Certain strains of Lactobacillus, including L. fermentum and L. plantarum, have been shown to reduce numbers of Enterobacteriaceae, which can disrupt the intestinal barrier.^[12] L. reuteri, L. rhamnosus, L. plantarum, and Bifidobacterium breve can help to restore the epithelium by reducing zonulin (which increases permeability) and increasing claudin 3.^[13]

 

L-glutamine

Glutamine is the most abundant amino acid in the body utilised by the intestinal endothelium. It has been shown to promote epithelial cell growth, enhance tight junction proteins (including occludin and claudins), suppress inflammation, and protect against permeability caused by stress, infection, or injury.^[14] Glutamine can be sourced from beef, fish, dairy, eggs, and nuts, but is also available in supplement form.

 

Zinc carnosine

Zinc L-carnosine is a pharmaceutical compound used to help repair intestinal damage in conditions such as ulcerative colitis and impaired intestinal permeability. It binds to damaged mucosa, reducing inflammation and protecting the lining from stress.^[15]

 

Lifestyle changes

Stress reduction

Chronic stress can prolong activation of the hypothalamic-pituitary-adrenal (HPA) axis, which may trigger an inflammatory response that harms the gastrointestinal tract.^[16]

Mindful eating – focusing on the food and the mind-body connection – helps to stimulate digestive processes and shift the nervous system toward parasympathetic dominance, which supports rest and repair processes.^[17]

 

Exercise

Low to moderate physical exercise stimulates muscle fibers to generate proteins and peptides called myokines, which have anti-inflammatory properties. Exercise also enhances gut microbiome diversity, increases SCFA production, improves nutrient utilization, and modulates hormones involved in the inflammatory process – all of which can contribute to gut barrier integrity.^[18]

The strength and integrity of the intestinal barrier is central to digestion, immune function, and overall wellbeing. If you are experiencing symptoms of leaky gut or other gastrointestinal concerns, some simple changes to your diet and lifestyle can support the healing process.

Please also consider seeking tailored advice from a healthcare professional.

This information is provided for educational purposes only and is not a substitute for professional medical advice. Always seek the guidance of your physician or qualified healthcare provider with any questions you may have regarding your health or a medical condition.

 

References

^[1] Sittipo, P., Choi, J., Lee, S., & Lee, Y. K. (2022). The function of gut microbiota in immune-related neurological disorders: a review. Journal of neuroinflammation, 19(1), 154. https://doi.org/10.1186/s12974-022-02510-1

^[2] 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

^[3] Di Vincenzo, F., Del Gaudio, A., Petito, V., Lopetuso, L. R., & Scaldaferri, F. (2024). 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

^[4] Aleman, R. S., Moncada, M., & Aryana, K. J. (2023). Leaky Gut and the Ingredients That Help Treat It: A Review. Molecules (Basel, Switzerland), 28(2), 619. https://doi.org/10.3390/molecules28020619

^[5] Fusco, W., Lorenzo, M. B., Cintoni, M., Porcari, S., Rinninella, E., Kaitsas, F., Lener, E., Mele, M. C., Gasbarrini, A., Collado, M. C., Cammarota, G., & Ianiro, G. (2023). Short-Chain Fatty-Acid-Producing Bacteria: Key Components of the Human Gut Microbiota. Nutrients, 15(9), 2211. https://doi.org/10.3390/nu15092211

^[6] Kaur, A. P., Bhardwaj, S., Dhanjal, D. S., Nepovimova, E., Cruz-Martins, N., Kuča, K., Chopra, C., Singh, R., Kumar, H., Șen, F., Kumar, V., Verma, R., & Kumar, D. (2021). Plant Prebiotics and Their Role in the Amelioration of Diseases. Biomolecules, 11(3), 440. https://doi.org/10.3390/biom11030440

^[7] Valentino, V., Magliulo, R., Farsi, D., Cotter, P. D., O’Sullivan, O., Ercolini, D., & De Filippis, F. (2024). Fermented foods, their microbiome and its potential in boosting human health. Microbial biotechnology, 17(2), e14428. https://doi.org/10.1111/1751-7915.14428

^[8] eethaler, B., Lehnert, K., Yahiaoui-Doktor, M. et al. Omega-3 polyunsaturated fatty acids improve intestinal barrier integrity—albeit to a lesser degree than short-chain fatty acids: an exploratory analysis of the randomized controlled LIBRE trial. Eur J Nutr 62, 2779–2791 (2023). https://doi.org/10.1007/s00394-023-03172-2

^[9] Raoul, P., Cintoni, M., Palombaro, M., Basso, L., Rinninella, E., Gasbarrini, A., & Mele, M. C. (2022). Food Additives, a Key Environmental Factor in the Development of IBD through Gut Dysbiosis. Microorganisms, 10(1), 167. https://doi.org/10.3390/microorganisms10010167

^[10] Lock, J. Y., Carlson, T. L., Wang, C. M., Chen, A., & Carrier, R. L. (2018). Acute Exposure to Commonly Ingested Emulsifiers Alters Intestinal Mucus Structure and Transport Properties. Scientific reports, 8(1), 10008. https://doi.org/10.1038/s41598-018-27957-2

^[11] Gou, H. Z., Zhang, Y. L., Ren, L. F., Li, Z. J., & Zhang, L. (2022). How do intestinal probiotics restore the intestinal barrier?. Frontiers in microbiology, 13, 929346. https://doi.org/10.3389/fmicb.2022.929346

^[12] Linninge, C., Xu, J., Bahl, M. I., Ahrné, S., & Molin, G. (2019). Lactobacillus fermentum and Lactobacillus plantarum increased gut microbiota diversity and functionality, and mitigated Enterobacteriaceae, in a mouse model. Beneficial microbes, 10(4), 413–424. https://doi.org/10.3920/BM2018.0074

^[13] Gou, H. Z., Zhang, Y. L., Ren, L. F., Li, Z. J., & Zhang, L. (2022). How do intestinal probiotics restore the intestinal barrier?. Frontiers in microbiology, 13, 929346. https://doi.org/10.3389/fmicb.2022.929346

^[14] Abbasi, F., Haghighat Lari, M.M., Khosravi, G.R. et al. A systematic review and meta-analysis of clinical trials on the effects of glutamine supplementation on gut permeability in adults. Amino Acids 56, 60 (2024). https://doi.org/10.1007/s00726-024-03420-7

^[15] Efthymakis, K., & Neri, M. (2022). The role of Zinc L-Carnosine in the prevention and treatment of gastrointestinal mucosal disease in humans: a review. Clinics and research in hepatology and gastroenterology, 46(7), 101954. https://doi.org/10.1016/j.clinre.2022.101954

^[16] La Torre, D., Van Oudenhove, L., Vanuytsel, T., & Verbeke, K. (2023). Psychosocial stress-induced intestinal permeability in healthy humans: What is the evidence?. Neurobiology of stress, 27, 100579. https://doi.org/10.1016/j.ynstr.2023.100579

^[17] Cherpak C. E. (2019). Mindful Eating: A Review Of How The Stress-Digestion-Mindfulness Triad May Modulate And Improve Gastrointestinal And Digestive Function. Integrative medicine (Encinitas, Calif.), 18(4), 48–53.

^[18] Varghese, S., Rao, S., Khattak, A., Zamir, F., & Chaari, A. (2024). Physical Exercise and the Gut Microbiome: A Bidirectional Relationship Influencing Health and Performance. Nutrients, 16(21), 3663. https://doi.org/10.3390/nu16213663