Screening and Referral
CF: Frequency of Nutrition Screening, Less Than 2 Years of Age
For infants and children with cystic fibrosis (CF) 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.
CF: Method of Nutrition Screening, Less Than 2 Years of Age
Infants and children with cystic fibrosis (CF) 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.
CF: Frequency of Nutrition Screening, 2-20 Years of Age
For children and adolescents with cystic fibrosis (CF) 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.
CF: Method of Nutrition Screening, 2-20 Years of Age
Pediatric individuals with cystic fibrosis (CF) 2-20 years of age, should be screened for nutrition risk by comparing growth percentiles and z-scores to general population norms using Centers for Disease Control (CDC) growth charts for the general population, since these parameters are longitudinally associated with lung function. Children and adolescents who have a body mass index (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.
CF: Frequency of Nutrition Screening, Adults
In adults with cystic fibrosis (CF) 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.
CF: Method of Nutrition Screening, Adults
Adults with cystic fibrosis (CF) 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.
Nutrition Assessment
CF: Frequency of Nutrition Assessment
In individuals with cystic fibrosis (CF), 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 6 months of life; up to every other month until 1 year of age; and up to quarterly until 2 years of age;
- annually for individuals greater than 2 years of age and;
- when disease or treatment course changes.
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.
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.
CF: Indirect Calorimetry
In pediatric (≤20 years of age) and adult individuals with cystic fibrosis (CF), 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.
CF: Estimating Energy Needs, Pediatrics
In pediatric individuals with cystic fibrosis (CF) ≤20 years of age, the RDN or international equivalent may estimate energy needs at each nutrition assessment using the recommonded dietary allowance (RDA) or Institute of Medicine (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, medications, physical activity, and disease severity.
CF: Estimating Energy Needs, Adults
In adults with cystic fibrosis (CF) greater 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, medications, physical activity, and disease severity.
CF: Dual-Energy X-Ray Absorptiometry (DEXA)
In individuals with cystic fibrosis (CF), 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.
CF: Single-Site Anthropometric Measures and Nutrition Focused Physical Exam
In all individuals with cystic fibrosis (CF), 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.
CF: Accuracy of Skinfold Measures and Bioelectrical Impedance Analysis (BIA)
In individuals with cystic fibrosis (CF), 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.
CF: Oral Glucose Tolerance Testing (OGTT)
For individuals with cystic fibrosis (CF) ≥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.
CF: Fat-Soluble Vitamins
For all individuals with cystic fibrosis (CF), 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.
CF: Lipid Profile
For individuals with cystic fibrosis (CF), 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.
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.
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 (CF). 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.
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).
CF: Dietary Patterns
For all individuals with cystic fibrosis (CF), 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.
CF: Meal and Snack Frequency
For all individuals with cystic fibrosis (CF), it is reasonable for the RDN or international equivalent to suggest frequent food intake throughout the day, including at least 3 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.
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.
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).
CF: Macronutrient Distribution
For individuals with cystic fibrosis (CF) 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.
CF: Fiber Intake
For individuals with cystic fibrosis (CF), the RDN or international equivalent may suggest dietary fiber intake in line with the Dietary Reference (DRI) 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, diarrha/steatorrhea (DIOS), or other gastrointestinal symptoms.
CF: Infant Feeding
In infants diagnosed with cystic fibrosis (CF), 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 forced expiratory volume in one second (FEV1%) predicted and decreased antibiotic use, but supplementation may be needed for infants with high nutrient requirements.
