Zonulin binds to receptors of the intestinal barrier and activates biochemical events that induce opening of the tight junctions and, as a consequence, increase the permeability of the intestinal epithelial cells so that various substances can pass through the intestinal barrier and trigger autoimmune reactions. IDK® Zonulin ELISA correlate with established metabolic traits related to increased intestinal permeability such as insulin resistance and obesity, as established in many publications.