Different types of mucinsin the intestine and the mucus layercovering IECs can act as a chemical barrier to protect IECs from invasionby pathogens and foreign harmful substances.107 Damage to the intestinal mucous layer caused by decreased mucinsecretion and impaired mucin polymer connections will lead to a varietyof intestinal diseases, such as inflammatory bowel disease (IBD),ulcerative colitis (UC), and type 2 diabetes mellitus (T2DM).108−110 The long-term or excessive use of certain drugs and toxins, suchas NSAIDs, alcohol, and chemicals, may directly damage the intestinalmucosal cells. This evidence concerns the gene MUC5AC and type 2 diabetes mellitus.