Zonulin is a protein released from intestinal epithelial cells that allows space for nutrients and molecules by loosening the relationship between the cells, which is part of a natural process. However, the gap may be larger than it should be, so that larger molecules of protein that should not pass, do pass through. Once these molecules enter the bloodstream, they trigger an immune response in the body. Gluten and intestinal bacteria can be a major contributor to an excessive gap between intestinal epithelial cells.
One of the components of gluten, called gliadin, raises the level of zonulin in the intestine, resulting in a strong loosening of the connection between cells. Thus, certain molecules can easily enter the space between the cells. The immune response they elicit causes damage to the structure of the intestinal epithelium, making it inflamed and permeable. This phenomenon is called permeable intestinal syndrome (intestinal permeability).
The goal of the test is the investigation of food intolerances causing intestinal inflammation and malabsorption. Zonulin is a marker of intestinal permeability (permeable intestinal syndrome).