title: Protein is an important but undervalued macronutrient in the nutritional care of patients with cystic fibrosis.
abstract: OBJECTIVE
  Achieving an optimal nutritional status in patients with cystic fibrosis (CF) is important to maintain better pulmonary function, physical performance, and to prolong survival. So far, nutrition care in CF has mainly focused on fat intake and achieving energy balance, but there is increasing information on the clinical importance of muscle maintenance and protein intake in CF.
  
  
  RESULTS
  Low muscle mass is consistently associated with pulmonary decline, bone mineral loss, and poor survival in CF. High energy and fat intake contributes to an increased prevalence of overweight and obesity in CF. Obesity per se is not related to better lung function in CF and has negative metabolic and clinical consequences, particularly when muscle wasting is present. Protein digestion capacity is severely impaired in CF, but high protein intake is needed and essential amino acid mixtures appear highly anabolic even in those with severe muscle loss.
  
  
  CONCLUSIONS
  Body composition assessment and achieving protein balance in the routine care in CF is important to prevent muscle loss and further improve the clinical and overall outcome of these patients. New approaches are needed to optimize the interaction between high essential amino-acid-rich protein intake and pancreatic enzyme regimen in CF. The optimal level of protein intake needs to be assessed in clinically stable CF patients as well as in those recovering from an acute exacerbation.
authors.affiliation: aDepartment of Health and Kinesiology, Center for Translational Research in Aging and Longevity, Texas A&M University, College Station, Texas bDepartment of Pediatric Pulmonology, University of Arkansas for Medical Sciences, Arkansas Children's Hospital, Little Rock, Arkansas, USA.
authors.forename: Mariëlle P K J
authors.initials: MP
authors.lastname: Engelen
authors.forename: Gulnur
authors.initials: G
authors.lastname: Com
authors.forename: Nicolaas E P
authors.initials: NE
authors.lastname: Deutz
mesh_terms: D000601:Amino Acids, Essential / Q000008:administration & dosage; D003550:Cystic Fibrosis / Q000178:diet therapy*; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D004734:Energy Metabolism; D006801:Humans; D008168:Lung / Q000378:metabolism; D009751:Nutritional Requirements; D009752:Nutritional Status; D018529:Nutritional Support / Q000379:methods*; D016032:Randomized Controlled Trials as Topic
chemical_list: D000601:Amino Acids, Essential; D004044:Dietary Proteins