What is Intestinal Permeability? Intestinal permeability, often referred to as "leaky gut," describes a condition where the integrity of the intestinal lining is compromised. The gut epithelium forms a critical barrier that regulates the passage of nutrients, water, and electrolytes while preventing the entry of pathogens, toxins, and undigested food particles into the bloodstream. This barrier is maintained by tight junction proteins such as occludin, claudins, and zonula occludens. When these