Cystic Fibrosis

CF: Executive Summary of Recommendations (2020)

Executive Summary of Recommendations  

Below are the recommendations and ratings for the Academy of Nutrition and Dietetics Cystic Fibrosis (CF) Evidence-Based Nutrition Practice Guideline. Use the links on the left to view the Guideline Introduction. Detailed recommendations, including the evidence supporting these recommendations, is available from the Major Recommendations tab.

Each Recommendation was developed from specific systematic review questions. Please download the "Relationship between PICO Questions and Recommendations" table (PDF) for details. 

For  a description of the Academy Recommendation Rating scheme (Strong, Fair, Weak, Consensus, Insufficient Evidence), click here.

  • Screening and Referral
    CF: Frequency of Nutrition Screening, Less Than 2 Years of Age
    For infants and children with cystic fibrosis less than 2 years of age, it is reasonable to measure weight and length at each clinic visit and to screen for risk of impaired growth and other nutrition concerns at least monthly for the first six months of age, every other month from 6-12 months of age, and quarterly from 12-24 months of age to identify nutrition risk.
    Consensus
    Imperative
    CF: Method of Nutrition Screening, Less Than 2 Years of Age
    Infants and children with cystic fibrosis less than 2 years of age should be screened for nutrition risk by comparing weight-for-age, weight-for-length and length-for-age z-scores or percentiles to birthweight and to growth norms using WHO growth charts for the general population, since these parameters are longitudinally associated with lung function. Children who are not maintaining birthweight, weight-for-length or length -for-age z-scores or who have depressed growth compared to the general population should be referred for full nutrition assessment by an RDN or international equivalent.
    Strong
    Imperative
    CF: Frequency of Nutrition Screening, 2-20 Years of Age
    For children and adolescents with cystic fibrosis ages 2-20 years, weight and height should be measured at each clinic visit and children should be screened for risk of impaired growth and other nutrition concerns at least quarterly or more frequently based on clinical condition to identify nutrition risk.
    Fair
    Imperative
    CF: Method of Nutrition Screening, 2-20 Years of Age
    Pediatric individuals with cystic fibrosis 2-20 years of age should be screened for nutrition risk by comparing growth percentiles and z-scores to general population norms using CDC growth charts for the general population, since these parameters are longitudinally associated with lung function. Children and adolescents who have a BMI-for age <50th percentile and/or who have concerning trends in BMI-for-age, weight-for-age or height-for-age z-scores should be referred for full nutrition assessment by an RDN or international equivalent.
    Strong
    Imperative
    CF: Frequency of Nutrition Screening, Adults
    In adults with cystic fibrosis  greater than 20 years of age, it is reasonable to measure weight and height at each clinic visit and to screen for malnutrition and/or other nutrition concerns at least quarterly or more frequently based on clinical condition to identify nutrition risk.
    Consensus
    Imperative
    CF: Method of Nutrition Screening, Adults
    Adults with cystic fibrosis greater than 20 years of age should be screened for nutrition risk by evaluating absolute values and trends in BMI, since BMI is longitudinally associated with lung function. Women who have a BMI <22 kg/m2, men who have a BMI <23 kg/m2, or adults who have concerning trends in BMI, either decreasing or increasing, should be referred for full nutrition assessment by an RDN or international equivalent.
    Fair
    Imperative
  • Nutrition Assessment
    CF: Frequency of Nutrition Assessment
    In individuals with cystic fibrosis, a full nutrition assessment should be conducted by an RDN or international equivalent
    • at diagnosis;
    • when indicated by nutrition screening;
    • up to monthly for the first six months of life; up to every other month until one year of age; and up to quarterly until two years of age;
    • annually for individuals greater than two years of age;
    • when disease or treatment course changes
    Consensus
    Imperative
    CF: Nutrition Assessment Components
    In individuals with cystic fibrosis (CF), the RDN or international equivalent should diagnose nutrition status, including underweight and overweight, based on a comprehensive assessment of weight and growth history and stature, body composition, disease severity, laboratory values, drug-nutrient interactions/implications, and estimated energy expenditure compared to client/parent report of dietary intake and food security status, since CF nutrition pathology is highly individual and maintaining optimal nutrition status is a necessary component of preventing disease progression.
    Strong
    Imperative
    CF: CFTR Modulators in Nutrition Assessment
    For individuals with cystic fibrosis (CF) of all ages who receive CFTR modulation therapy, the RDN or international equivalent should continue to conduct nutrition screening with nutrition assessment as indicated based on age, since these medications may change nutrient needs for some individuals with CF.
    Fair
    Imperative
    CF: Indirect Calorimetry
    In pediatric (≤20 years of age) and adult individuals with cystic fibrosis, it is reasonable for the RDN or international equivalent to measure energy needs using indirect calorimetry, when feasible and indicated, since indirect calorimetry is the gold standard for measuring energy expenditure in clinical settings. 
    Consensus
    Conditional
    CF: Estimating Energy Needs, Pediatrics
    In pediatric individuals with cystic fibrosis ≤20 years of age, the RDN or international equivalent may estimate energy needs at each nutrition assessment using the RDA or IOM active lifestyles formulas, since these formulas were the most accurate compared to indirect calorimetry in this population. Energy needs should be individualized based on growth history, nutrition status and medications, physical activity and disease severity.
    Weak
    Conditional
    CF: Estimating Energy Needs, Adults
    In adults with cystic fibrosis (CF) great than 20 years of age, the RDN or international equivalent may estimate energy needs annually or with unintentional weight changes using standard energy expenditure equations x 1.25, since estimated energy requirements for the general population may underestimate needs in adults with CF.  Energy needs should be individualized based on nutrition status and medications, physical activity and disease severity.
    Weak
    Conditional
    CF: Dual-Energy X-Ray Absorptiometry (DEXA)
    In individuals with cystic fibrosis, it is reasonable for the RDN or international equivalent to assess body composition using dual-energy X-ray absorptiometry (DEXA), when feasible and available, since DEXA is the gold standard in clinical settings.   
    Consensus
    Conditional
    CF: Single-Site Anthropometric Measures and Nutrition Focused Physical Exam
    In all individuals with cystic fibrosis, when body composition assessment with dual-energy X-ray absorptiometry (DEXA) is not feasible or indicated, it is reasonable for the RDN or international equivalent to assess mid-upper arm circumference with single site skinfold measures and/or Nutrition-Focused Physical Exams at each nutrition assessment in order to aid in the classification of nutrition status over time.
    Consensus
    Conditional
    CF: Accuracy of Skinfold Measures and Bioelectrical Impedance Analysis (BIA)
    In individuals with cystic fibrosis, when dual-energy X-ray absorptiometry (DEXA) is not feasible or indicated, the RDN or international equivalent may use age-appropriate tests including skinfold measures or bioelectrical impedance analysis (BIA) with caution when tracking body composition over time, understanding that prediction equations using these methods may over- or under-estimate absolute fat and fat-free mass.
    Weak
    Conditional
    CF: Oral Glucose Tolerance Testing (OGTT)
    For individuals with cystic fibrosis ≥10 years of age who have not previously been diagnosed with diabetes, oral glucose tolerance testing (OGTT) is recommended annually or as indicated by glucose levels and clinical signs and symptoms (weight loss, increase in pulmonary exacerbations and/or loss of lung function) during nutrition assessment, since progression to CFRD is a risk factor for pulmonary decline and mortality.
    Strong
    Conditional
    CF: Fat-Soluble Vitamins
    For all individuals with cystic fibrosis, regardless of exocrine pancreatic function, it is reasonable for the RDN or international equivalent to assess fat-soluble vitamin levels at least annually, since there may be high risk of fat-soluble vitamin abnormality due to pancreatic insufficiency and malabsorption.
    Consensus
    Conditional
    CF: Lipid Profile
    For individuals with cystic fibrosis, it is reasonable for the RDN or international equivalent to evaluate fasting lipid profile at least once between the ages of 10 and 20 years and every 4-6 years thereafter, or more frequently if the individual has multiple risk factors for cardiovascular disease, in order to detect and prevent dyslipidemia.
    Consensus
    Conditional
  • Nutrition Intervention
    CF: MNT Approach
    RDNs or international equivalents should collaborate with all individuals with cystic fibrosis (CF), their families, and interdisciplinary healthcare teams to co-produce individualized Medical Nutrition Therapy (MNT) based upon the individual’s personal preferences, psychological and psychosocial factors, physiological needs, health status, and pharmacological interventions. MNT for individuals with CF should include comprehensive nutrition assessment and appropriate interventions, including individualized modification of diet, dietary supplements including micronutrient supplements, and pancreatic enzymes, in order to maintain or improve nutrition status and symptoms over time.
    Fair
    Imperative
    CF: MNT Full Time Equivalents (FTEs)
    It is reasonable for one FTE RDN or international equivalent to provide care for 75-150 individuals with cystic fibrosis. A caseload at the lower end of this range is appropriate for dietitians who work primarily with the pediatric population or adults with advanced disease and/or co-morbidities in order to deliver continuous, high-quality nutrition care that effectively manages nutrition challenges and prevents disease decline.
    Consensus
    Conditional
    CF: Food and Supplement Intake
    For all individuals with cystic fibrosis (CF), it is reasonable for the RDN or international equivalent to advise an age-appropriate, healthy diet that emphasizes culturally appropriate foods associated with positive health outcomes in the general population, including vegetables, fruits, whole grains, seafood, eggs, beans and peas, nuts and seeds, dairy products, and meats and poultry, as tolerated and preferred by the individual with CF, since there is no evidence to suggest that routine modification from a well-balanced, healthy diet is associated with improved outcomes. It is reasonable to advise supplementation with energy and/or protein dense foods or oral or enteral supplements, as needed to achieve or maintain normal growth (pediatrics) or BMI status (adults).
    Consensus
    Conditional
    CF: Dietary Patterns
    For all individuals with cystic fibrosis, it is reasonable for the RDN or international equivalent to consider advising a dietary pattern, individualized for dietary preferences and nutrient needs, that promotes consumption of nutrient-dense foods, including healthy fats and micronutrients.
    Consensus
    Imperative
    CF: Meal and Snack Frequency
    For all individuals with cystic fibrosis, it is reasonable for the RDN or international equivalent to suggest frequent food intake throughout the day, including at least three meals with snacks in between, as needed, in order to meet energy and protein needs and achieve or maintain optimal weight/growth and nutrition status.
    Consensus
    Conditional
    CF: Food Intake with CF-Related Diabetes
    For all individuals with cystic fibrosis-related diabetes (CFRD), it is reasonable for the RDN or international equivalent to consider advising a diet consistent with general, age-appropriate healthy dietary recommendations and individualize as needed according to CFRD pathology. It is reasonable for the RDN to emphasize limiting high-sugar foods and beverages with low nutrient density, due to adverse effects on blood glucose levels.
    Consensus
    Conditional
    CF: Food Intake with Overweight/Obesity
    For individuals with cystic fibrosis (CF) who are overweight or obese, it is reasonable for the RDN or international equivalent to advise an age-appropriate diet that emphasizes foods associated with positive health outcomes in the general population, including vegetables, fruits, whole grains, seafood, eggs, beans and peas, nuts and seeds, dairy products, and meats and poultry, as tolerated and preferred by the individual with CF, with energy needs adjusted to achieve or maintain normal growth (pediatrics) or BMI status (adults).
    Consensus
    Conditional
    CF: Macronutrient Distribution
    For individuals with cystic fibrosis who are not at risk of malnutrition, the RDN or international equivalent may suggest consuming macronutrients (carbohydrates, protein and fat) in the same percentage distribution as is recommended for the typical, age-matched population, since there is no current evidence to suggest benefits from modified macronutrient distribution.
    Weak
    Conditional
    CF: Fiber Intake
    For individuals with cystic fibrosis, the RDN or international equivalent may suggest dietary fiber intake in line with the dietary reference intake for the general population, as tolerated on an individual basis, since evidence suggests fiber intake at the recommended level does not increase risk of constipation, DIOS or other gastrointestinal symptoms.
    Weak
    Conditional
    CF: Infant Feeding
    In infants diagnosed with cystic fibrosis, the RDN or international equivalent should recommend providing as much breast milk as possible, with breast milk fortification and formula supplementation as necessary for the first year of life, to regain birthweight z-score and achieve normal growth for age. Breastfeeding is associated with improved FEV1% predicted and decreased antibiotic use, but supplementation may be needed for infants with high nutrient requirements.
    Fair
    Conditional
 

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