Exocrine pancreatic insufficiency (EPI) is the inability to properly digest food due to a lack or reduction of digestive enzymes made by the pancreas. EPI can occur in humans and is prevalent in many conditions such as cystic fibrosis, Shwachman–Diamond syndrome, different types of pancreatitis, multiple types of diabetes mellitus (Type 1 and Type 2 diabetes), advanced renal disease, older adults, celiac disease, IBS-D, IBD, HIV, alcohol-related liver disease, Sjogren syndrome, tobacco use, and use of somatostatin analogues. It also occurs in dogs and other animals. EPI is caused by a progressive loss of the pancreatic cells that make digestive enzymes; loss of digestive enzymes leads to maldigestion and malabsorption of nutrients from normal digestive processes. EPI can cause symptoms even before reaching the stages of malnutrition: ‘mild’ or ‘moderate’ EPI is when fecal elastase levels are <200 ug/g, whereas ‘severe’ EPI is considered to be when fecal elastase levels is <100 ug/g. Chronic pancreatitis is the most common cause of EPI in cats. In dogs, the most common cause is pancreatic acinar atrophy, arising as a result of genetic conditions, a blocked pancreatic duct, or prior infection. The exocrine pancreas is a portion of this organ that contains clusters of ducts (acini) producing bicarbonate anion, a mild alkali, as well as an array of digestive enzymes that together empty by way of the interlobular and main pancreatic ducts into the duodenum (upper small intestine). The hormones cholecystokinin and secretin secreted by the stomach and duodenum in response to distension and the presence of food in turn stimulate the production of digestive enzymes by the exocrine pancreas. The alkalization of the duodenum neutralizes the acidic chyme produced by the stomach that is passing into it; the digestive enzymes serve to catalyze the breakdown of complex foodstuffs into smaller molecules for absorption and integration into metabolic pathways. The enzymes include proteases (trypsinogen and chymotrypsinogen), hydrolytic enzymes that cleave lipids (the lipases phospholipase A2 and lysophospholipase, and cholesterol esterase), and amylase to digest starches. EPI results from progressive failure in the exocrine function of the pancreas to provide its digestive enzymes, often in response to a genetic condition or other disease state, resulting in the inability of the animal involved to properly digest food. Signs and symptoms Loss of pancreatic enzymes leads to maldigestion and malabsorption. Other symptoms may include: Abdominal discomfort or pain Bloating Diarrhea anemia (Vitamin B12, iron, folate deficiency)