LEAKY GUT & THE MUCOUS 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.

Gut dysbiosis and cows’ milk protein allergy (CMPA) — is there a link?

Gut dysbiosis means an unhealthy imbalance of bacteria in the gut, which can increase the chance of developing a cow’s milk protein allergy (CMPA). Factors like how a baby is born, what they eat, and antibiotics can affect this balance. Babies with CMPA often have fewer good bacteria, which can affect their immune system. Using special supplements called synbiotics (prebiotics plus probiotics) may help restore healthy gut bacteria and support the immune system.

Biofilms by bacterial human pathogens: Clinical relevance - development, composition and regulation - therapeutical strategies

This article explains that bacterial biofilms—clusters of bacteria encased in a slimy protective layer—are a major factor in chronic infections. Biofilms form on medical devices, wounds, and tissues, making infections harder to treat. They protect bacteria from antibiotics and the immune system, allowing bacteria to persist and cause long-term health problems. Understanding biofilm formation is crucial for developing better treatments for persistent infections.

Regulation of Intestinal Epithelial Cells Properties and Functions by Amino Acids

The article discusses the roles of intestinal epithelial cells (IECs) in maintaining gut health. IECs form a protective barrier, facilitate nutrient absorption, and defend against harmful microorganisms. The paper highlights how various factors, including diet, inflammation, and gut microbiota, influence the function and integrity of IECs. Understanding these interactions is essential for developing strategies to manage gastrointestinal diseases and promote overall health.

Exploring the role and diversity of mucins in health and disease with special insight into non-communicable diseases

This review discusses mucins, which are large glycoproteins found in mucus that coat and protect the surfaces of organs like the lungs, gut, and urogenital tract. Mucins help prevent infection, dehydration, and physical damage, and also aid in moving materials through these tracts. The article explains that mucins are produced by goblet cells and are encoded by the MUC gene family. They have a high molecular weight and contain heavily glycosylated domains. The size and number of these domains can vary between individuals due to genetic differences, which may serve as markers for certain conditions. The review also highlights that while mucins protect against harmful substances, malfunction or imbalance in mucin production can contribute to various diseases, including non-communicable diseases like cancer, chronic respiratory diseases, and gastrointestinal disorders.

Mucin-type O-glycans and their roles in intestinal homeostasis

This review discusses mucin-type O-glycans, complex sugar molecules attached to proteins in the gut lining. These glycoproteins are crucial for maintaining gut health by forming a protective mucus layer that shields the intestinal lining from pathogens and mechanical damage. The authors highlight how alterations in the structure or production of these mucins can lead to intestinal inflammation and diseases such as inflammatory bowel disease (IBD). They also explore how gut bacteria interact with these mucins, influencing both gut health and disease.

Human Intestinal Barrier Function in Health and Disease

This review discusses the importance of the intestinal barrier in maintaining gut health and its role in various diseases. The authors explain that the intestinal barrier consists of a physical layer of epithelial cells, tight junctions, and mucus, which protect against harmful substances and pathogens. Disruption of this barrier can lead to increased intestinal permeability, often referred to as “leaky gut,” which has been associated with conditions like inflammatory bowel disease, irritable bowel syndrome, and metabolic disorders. The review also explores factors that can influence intestinal barrier function, including diet, microbiota, and genetic predisposition, and discusses potential therapeutic strategies to restore barrier integrity.

Role of non-steroidal anti-inflammatory drugs on intestinal permeability and nonalcoholic fatty liver disease

This review examines how non-steroidal anti-inflammatory drugs (NSAIDs), commonly used for pain relief, can affect the gut and liver. The authors discuss how NSAIDs can increase intestinal permeability, often referred to as "leaky gut," which may allow harmful substances to enter the bloodstream and potentially contribute to liver damage. They also explore the link between NSAID use and the development of nonalcoholic fatty liver disease (NAFLD), a condition characterized by fat accumulation in the liver not caused by alcohol consumption. The review emphasizes the need for careful use of NSAIDs, especially in individuals with existing gut or liver conditions.

Mucus: An Underestimated Gut Target for Environmental Pollutants and Food Additives

This review discusses how environmental pollutants and food additives can affect the mucus layer in the gut. The authors explain that the mucus layer acts as a protective barrier, shielding the gut lining from harmful substances. However, certain chemicals, including pollutants and additives, can disrupt this barrier, leading to increased gut permeability and potential inflammation. The review emphasizes the importance of considering the impact of these substances on the mucus layer when evaluating their overall effects on gut health.

Mucus barrier, mucins and gut microbiota: the expected slimy partners?

This article explores the intricate relationship between the intestinal mucus layer, mucins, and the gut microbiota. The gastrointestinal tract is a complex system that serves as a primary interface between the body and the external environment, hosting a vast community of microbes. The intestinal mucus layer, primarily composed of mucins, acts as a crucial barrier protecting the gut lining from pathogens and maintaining gut homeostasis. Recent research has highlighted the dynamic interplay between this mucus barrier and the gut microbiota. The composition and function of the mucus layer can influence microbial colonization and diversity, while the microbiota can, in turn, modulate the structure and function of the mucus barrier. Disruptions in this balance have been implicated in various gastrointestinal disorders, including inflammatory bowel diseases. The article emphasizes the importance of understanding this 'slimy' partnership to develop therapeutic strategies aimed at restoring mucus barrier integrity and promoting a healthy gut microbiota.

Biofilms & Why You Need A Biofilm Disruptor

The article by Dr. Amy Myers explains that biofilms are clusters of microorganisms—such as bacteria, fungi, and parasites—encased in a protective slime layer. These biofilms can form in various parts of the body, including the gut, and are notoriously difficult to eliminate. In the digestive system, biofilms can disrupt digestion, weaken immunity, and contribute to conditions like Candida overgrowth. To address this, Dr. Myers recommends biofilm disruptors—supplements designed to break down these protective layers.