LEAKY GUT | INTESTINAL BARRIER

Partners in Leaky Gut Syndrome: Intestinal Dysbiosis and Autoimmunity

The article explores how an imbalance in gut bacteria (dysbiosis) and a compromised intestinal barrier (leaky gut syndrome) may contribute to autoimmune diseases like type 1 diabetes, multiple sclerosis, rheumatoid arthritis, and celiac disease. Normally, the gut lining acts as a barrier, preventing harmful substances from entering the bloodstream. However, when this barrier weakens, it allows bacteria and their by-products to leak into the body, triggering inflammation and immune system overactivity. The article discusses how certain immune cells and molecules, such as IL-22, play roles in maintaining or disrupting this barrier. It also highlights that the gut microbiota influences immune responses, and disruptions in its composition can lead to systemic inflammation and autoimmune conditions.

Fight them or feed them: how the intestinal mucus layer manages the gut microbiota

This article explains how the mucus layer in our intestines acts like a protector and caretaker for the bacteria living there. It keeps harmful germs away from our gut wall while feeding the good bacteria by providing nutrients. The types of bacteria and the mucus work together to keep the gut healthy. But if the mucus gets damaged—like from a poor diet—it can let bad bacteria in, which might cause gut problems and inflammation.

Gut Structure, Function & Barrier

This article on leaky gut explains that this condition arises when the intestinal lining becomes damaged, allowing harmful substances like bacteria and undigested food particles to leak into the bloodstream. This can trigger widespread inflammation and immune system responses, leading to symptoms such as bloating, fatigue, food sensitivities, joint pain, brain fog, and skin issues. Potential causes include poor diet, chronic stress, overuse of antibiotics, low stomach acid, and conditions like small intestinal bacterial overgrowth (SIBO). The article also discusses how leaky gut may contribute to autoimmune diseases and suggests that restoring gut health through dietary changes, reducing inflammation, and supporting the immune system can help manage the condition.

Integrity of the Intestinal Barrier: The Involvement of Epithelial Cells and Microbiota—A Mutual Relationship

This article explores how the cells lining the gut, known as epithelial cells, and the gut bacteria (microbiota) work together to maintain a healthy gut barrier. This barrier is crucial for protecting against harmful substances and infections. The review discusses how different types of epithelial cells contribute to this protective layer and how the gut bacteria influence the function of these cells. It also highlights how disruptions in this relationship can lead to gut inflammation and diseases.

All disease begins in the (leaky) gut: role of zonulin-mediated gut permeability (F1000Research / Fasano, 2020)
Alessio Fasano’s open review popularized the zonulin concept: zonulin regulates tight junctions and, when over-released (by bacteria, gluten, etc.), increases gut permeability — a candidate mechanism linking environmental triggers to autoimmunity and chronic inflammation. The paper is influential and frames many subsequent barrier studies.

The influence of nutrition on intestinal permeability and the microbiota (Frontiers in Nutrition, 2022)
This review explains how dietary patterns (fiber, polyphenols, processed food, alcohol) shape both the microbiome and the gut barrier. It argues that nutrition is a practical lever to restore barrier integrity and microbial balance (e.g., fiber → SCFAs → tighter junctions).

A mechanism by which gut microbiota elevates permeability and inflammation in obese/diabetic mice and human gut (Gut, 2023)
This mechanistic study shows how microbial products from dysbiotic communities raise intestinal permeability and local inflammation in obesity/diabetes models, linking microbial shifts to metabolic-inflammation via barrier disruption. The paper combines mouse experiments and human samples for translational relevance.

Antibiotic-induced disruption of gut microbiota alters local metabolite profiles and immune responses (Frontiers in Cellular and Infection Microbiology, 2019)
This experimental study demonstrates that antibiotics can create dysbiosis that changes metabolite production (e.g., SCFAs) and impairs local barrier and immune functions — a useful model for showing how microbiome perturbation causes barrier-related immune effects.

The intestinal barrier: a pivotal role in health, inflammation and disease (The Lancet Gastroenterology & Hepatology, 2025)
A recent comprehensive review describing the multi-layered intestinal barrier (epithelial cells, mucus, immune layer), how microbes and their metabolites modulate each layer, and how barrier failure underlies diverse disorders from IBD to metabolic disease.

Intestinal permeability in inflammatory bowel disease: pathogenesis and clinical implications (Review, 2015)
A foundational open review that describes how barrier defects and dysbiosis drive IBD pathogenesis, the evidence for barrier markers in patients, and how therapies that restore barrier function can help induce and maintain remission.

Breaking down the barriers: the gut microbiome, intestinal permeability and the brain (Frontiers in Cellular Neuroscience, 2015)
One of the earlier syntheses of the gut–brain–barrier triangle; it reviews how alcohol, stress and dysbiosis increase permeability, how translocated microbial products affect brain inflammation and behaviour, and how restoring microbial balance can normalise barrier and brain outcomes.

Intestinal Permeability in Disorders of Gut–Brain Interaction (IBS)

This article discusses the role of intestinal permeability in disorders of gut–brain interaction, such as irritable bowel syndrome. The authors review evidence linking gut barrier dysfunction to these conditions and suggest potential therapeutic approaches.

Markers of Gastrointestinal Permeability in Polycystic Ovary Syndrome (PCOS)

This study explored the relationship between altered intestinal permeability and gut microbiota dysbiosis in women with PCOS. The findings indicate that gut barrier dysfunction may play a role in the pathogenesis of PCOS, highlighting the need for further investigation into gut health in this population.