Digestive system dysfunction in cystic fibrosis: Challenges for nutrition therapy

Li Li, Shawn Somerset
2014 Digestive and Liver Disease  
Cystic fibrosis can affect food digestion and nutrient absorption. The underlying mutation of the cystic fibrosis trans-membrane regulator gene depletes functional cystic fibrosis trans-membrane regulator on the surface of epithelial cells lining the digestive tract and associated organs, where Cl − secretion and subsequently secretion of water and other ions are impaired. This alters pH and dehydrates secretions that precipitate and obstruct the lumen, causing inflammation and the eventual
more » ... adation of the pancreas, liver, gallbladder and intestine. Associated conditions include exocrine pancreatic insufficiency, impaired bicarbonate and bile acid secretion and aberrant mucus formation, commonly leading to maldigestion and malabsorption, particularly of fat and fat-soluble vitamins. Pancreatic enzyme replacement therapy is used to address this insufficiency. The susceptibility of pancreatic lipase to acidic and enzymatic inactivation and decreased bile availability often impedes its efficacy. Brush border digestive enzyme activity and intestinal uptake of certain disaccharides and amino acids await clarification. Other complications that may contribute to maldigestion/malabsorption include small intestine bacterial overgrowth, enteric circular muscle dysfunction, abnormal intestinal mucus, and intestinal inflammation. However, there is some evidence that gastric digestive enzymes, colonic microflora, correction of fatty acid abnormalities using dietary n − 3 polyunsaturated fatty acid supplementation and emerging intestinal biomarkers can complement nutrition management in cystic fibrosis. (S. Somerset). [3]. Although the exact manifestation is site-specific, the common pathophysiology is described above. Numerous studies on single or multiple challenges in the digestive system in CF have been published. This review aims to integrate the manifestations and complications of CF throughout the entire digestive system and the changes in the digestion of food and absorption of nutrients to highlight the potential impact on nutrient acquisition and nutritional status in CF. Factors influencing digestion and absorption Pancreatic manifestations of CF and lipid maldigestion and malabsorption Despite its exo-gastrointestinal anatomical location, the pancreas is the major organ responsible for the digestion of carbohydrate, protein and lipid through the secretion of various digestive enzymes into the duodenum [4]. These enzymes mainly include pancreatic amylase, protease, lipase and colipase. Pancreatic acinar cells secrete inactive pancreatic digestive enzymes into the acinar lumen, which extends to the pancreatic ducts [3, 5] .
doi:10.1016/j.dld.2014.06.011 pmid:25053610 fatcat:lreeyhh5wvdkhohchncfdjphya