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Cystic Fibrosis

Cystic fibrosis (CF) is a life-threatening inherited condition, characterised by widespread exocrine gland dysfunction. The consequence of this disease is recurrent chest infections, pancreatic enzyme deficiency and excessive electrolyte losses in sweat. Thick secretions block the lungs and the pancreatic duct which leads to chest infections and pancreatic insufficiency.[1]

47% percent of infants, 34% of adolescents and 44% of newly diagnosed CF patients are at risk of undernutrition.[2] Nutritional problems may occur due to a combination of increased energy expenditure (chest infection, difficulty breathing, fever, medication), decreased dietary intake and pancreatic insufficiency (malabsorption due to lack of enzymes).[1]

Nutritional recommendations are currently 120-150% of estimated energy requirements for weight, with 40% of total energy coming from fat.[3] Protein should also be increased to compensate for the excessive nitrogen losses in faeces and sputum.[3] Due to the higher needs of CF patients a non-supplemented diet can rarely meet their nutritional needs and oral supplements (or in some cases tube feeding) are often recommended.[3]

In undernourished cystic fibrosis patients (adults and children), oral nutritional supplements and enteral tube feeding have been shown to increase nutritional intakes, to increase growth, to improve pulmonary function, and to positively impact life expectancy.[4-7] Achieving optimal nutritional intake and catch-up in weight gain within the first two years of diagnosis in children with CF was the single strongest predictor of lung function improvement at 6 years of age, which is correlated to reduced morbidity and mortality.[5]

References

  1. Kleinman RE (ed). Nutrition in cystic fibrosis. In: Pediatric Nutrition Handbook. Policy of the American Academy of Pediatrics. Elk Grove Village, 6th edition 2009:1001.
  2. Lai HC, Kosorok MR, Sondel SA, et al. Growth status in children with cystic fibrosis based on the National Cystic Fibrosis Patient Registry data: evaluation of various criteria used to identify malnutrition. Journal Pediatrics 1998;132:478-85.
  3. Thomas B, Bishop J. Manual of Dietetic Practice. 4th edn. Oxford, Blackwell publishing, 2007.
  4. Steinkamp G, Wiedemann B. Relationship between nutritional status and lung function in cystic fibrosis: cross sectional and longitudinal analyses from the German CF quality assurance (CFQA) project. Thorax 2002;57:596-601.
  5. Lai HJ, Shoff SM, Farrell PM; Wisconsin Cystic Fibrosis Neonatal Screening Group. Recovery of birth weight z score within 2 years of diagnosis is positively associated with pulmonary status at 6 years of age in children with cystic fibrosis. Pediatrics 2009;123:714-22.
  6. Chaves CR, Britto JA, Oliveira CQ, et al. Association between nutritional status measurements and pulmonary function in children and adolescents with cystic fibrosis. J Bras Pneumol 2009;35:409-14.
  7. Corey M, McLaughlin FJ, Williams M, et al. A comparison of survival, growth and pulmonary function in patients with cystic fibrosis in Boston and Toronto. J Clin Epidemiol 1988;41:583-91.