Travel to Health

Key Points Epithelial layer Tight junctions Zonulin Permeability mechanisms The Gut Barrier: Your First Line of Defense The human body contains many protective barriers—including those in the gut, airways, skin, oral cavity, vagina, placenta, and brain (via the blood–brain barrier). This article focuses on the intestinal barrier, one of the most important interfaces between the external environment and the immune system. Under ideal digestive conditions, only small, fully broken‑down nutrients should pass from the gut into the bloodstream. When this barrier becomes compromised, larger particles may slip through—a phenomenon often referred to as increased intestinal permeability or “ leaky gut .” The Brick‑and‑Mortar Model The gastrointestinal tract spans roughly 300–400 sq. m., and only a single epithelial layer separates the body from vast amounts of dietary and microbial antigens. [1,2] These epithelial cells are held together by a “brick‑and‑mortar” system known as tight junctions...

The human body contains many protective barriers, including those in the gut, airways, skin, oral cavity, vagina, and placenta . Here, we focus on the barrier within the gut. Under ideal digestive conditions, only small, fully broken‑down nutrients should enter the bloodstream. This process is disrupted when intestinal permeability increases, often referred to as ‘ leaky gut .’ Stop Wasting Money on Probiotics. Here’s What Actually Improves Gut Health  (YouTube  link ) Bricks and Mortar Model The gastrointestinal tract covers roughly 300–400 sq. m., with only a single epithelial layer separating the body from large amounts of dietary and microbial antigens. [25] These epithelial cells are connected by a “brick‑and‑mortar” system known as tight junctions . [14,23] In this model: Bricks : intestinal epithelial cells Mortar : the tight junctions that seal the spaces between them Researchers at the University of Maryland School of Medicine and Harvard Medical School iden...