CFTR and cystic fibrosis: Multiple factors related to CFTR dysfunction have been associated with poor nutritional status in people with CF including increased pancreatic dysfunction in the form of exocrine pancreatic insufficiency (EPI or PI), CF-related diabetes, and impaired bicarbonate secretion; increased fatty acid turnover and energy expenditure; and factors associated with enteric homeostasis including bile salt loss in stool, increased inflammation, and small intestinal bacterial overgrowth [19].