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Cystic Fibrosis

CF: About Cystic Fibrosis (2019)

Cystic Fibrosis (CF) is a genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. These mutations result in the production of thick, sticky mucus in multiple organ systems, including the pulmonary and gastrointestinal (GI) systems. In the pulmonary system, this thick and sticky mucus decreases lung function, resulting in increased energy expenditure. In the GI system, this mucus can build up in the pancreas, resulting in pancreatic insufficiency and, consequently, impaired digestion and absorption of nutrients (CF Foundation, About CF). Approximately 85% of people with CF are pancreatic insufficient (Singh et al 2017), which may result in impaired insulin production and CF-related diabetes (CFRD). Approximately 40-50% of adults with CF are affected by CFRD (Kayani et al 2018). Because people with CF have higher energy needs and decreased nutrient absorption, there is higher risk of malnutrition. In people with CF, undernutrition is associated with decreased lung function (CFF Patient Registry 2017). 

Because of these complex nutrition challenges and needs for people with CF and the critical consequences of malnutrition in this population, individualized nutrition counselling and care from a Registered Dietitian Nutritionist (RDN) is considered an integral aspect of CF care. CF RDNs work with and counsel people with CF, their families, and their health care teams in order to implement effective, realistic strategies to maintain and improve nutrition status and prevent disease decline. 

In the past, CF was largely considered a pediatric disease. Over the past thirty years, nutrition management has focused improving and maintaining nutrition status through a high energy, high fat diet as well as management of pancreatic enzyme replacement therapy (Borowitz et al 2002, Haller et al 2014, Sutherland et al 2018, Turck et al 2016). However, with improved treatments, the prognosis for CF has improved significantly, resulting in less severe symptoms and increased survival (CFF Patient Registry data 2017). This changing landscape in CF has required RDNs and other health care professionals to re-examine how to optimally deliver nutrition care to people with CF. New considerations must balance the risks of undernutrition, which is associated with decline in pulmonary function (CFF Patient Registry 2017), with risks of chronic diseases that are associated with longer life span, such as cardiovascular disease, diabetes progression and certain cancers. 

In 2018, the Evidence Analysis Center (EAC) at the Academy of Nutrition and Dietetics conducted an evidence scoping review to examine if there was enough current evidence to justify creating an evidence practice guideline for nutrition counselling and care for people with CF (Rozga et al 2019). This scoping review elucidated that many nutrition topics in CF have been examined in regularly updated systematic reviews from high-quality organizations such as the Cochrane Collaboration. Moreover, two recent, comprehensive evidence-based practice guidelines on CF care had recently been published by the Thoracic Society of Australia/New Zealand (2017) and ESPEN-ESPGHAN-ECFS (2016). However, evidence examining the effect of medical nutrition therapy (MNT) provided by an RDN and of dietary intake on nutrition-related outcomes in CF was sparse. In addition, it is unclear if or how nutrition screening and assessment should be modified to accommodate changing trends in the CF population and in treatment. There is a need to examine which nutrition parameters are most appropriate for use in the CF population using evidence-based methods, since people with CF may have lower lean mass and bone density (Calella et al P), fluid volume depletion (Scurati-Manzoni et al 2014) and are at higher risk of malnutrition. 

References:

  • Borowitz D, Baker R, Stallings V.  Consensus Report on Nutrition for Pediatric Patients with Cystic Fibrosis. Journal of Pediatric Gastroenterology and Nutrition. 2002; 35:246-259. 
  • CalellaP, Valerio G, Brodlie M, Donini LM, Siervo M. Cystic fibrosis, body composition, and health outcomes: a systematic review. Nutrition. 2018;55-56:131-139.
  • Cystic Fibrosis Foundation. About Cystic Fibrosis. Available at https://www.cff.org/What-is-CF/About-Cystic-Fibrosis/. Accessed June 18, 2019.
  • Cystic Fibrosis Foundation Patient Registry. 2017 Annual Data Report. Bethesda, Maryland. 
  • Haller W, Ledder O, Lewindon P, Couper R, Gaskin K, Oliver M.  Cystic Fibrosis: An update for clinicians. Part 1: Nutrition and gastrointestinal complications.  Journal of Gastroenterology and Hepatology. 2014; 29: 1344-1355. 
  • Kayani K, Mohammed R, Mohiaddin. Cystic Fibrosis-Related Diabetes. Front Endocrinol (Lausanne). 2018;9:20. 
  • Saxby N, Painter C, Kench A, King S, Crowder T, van der Haak N and the Australian and New ZealandCystic Fibrosis Nutrition Guideline Authorship Group (2017). Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand, ed. Scott C. Bell, Thoracic Society of Australia and New Zealand, Sydney.
  • Scurati-Manzoni E, Fossali EF, Agostoni C, et al. Electrolyte abnormalities in cystic fibrosis: systematic review of the literature. Pediatr Nephrol. 2014;29(6):1015-23.
  • Singh VK, Schwarzenberg SJ. Pancreatic insufficiency in Cystic Fibrosis. J Cyst Fibros. 2017;Suppl2:S70-S78. 
  • Sutherland R, Katz T, Liu V, et al. Dietary intake of energy-dense, nutrient-poor and nutrient-dense food sources in children with cystic fibrosis. J Cyst Fibros. 2018;17(6):804-810.
  • Turck D et al., ESPEN-ESPGHAN-ECFS guidelines on nutrition care for infants, children and adults with cystic fibrosis. Clinical Nutrition. 2016; 35:557-577.