title: Individualized vitamin A supplementation for patients with cystic fibrosis.
abstract: OBJECTIVE
  To determine the vitamin A status and appropriate supplementation dosage of cystic fibrosis (CF) patients who received vitamin A supplementation based on annual serum retinol measurements.
  
  
  METHODS
  Vitamin A food intake, supplementation dosage, and serum retinol levels were obtained for 32 CF patients >4 years of age (4.3-27.3 years old) who had pancreatic insufficiency and mild-to-moderate lung disease (percent predicted of forced expiratory volume in 1 s > 40%). These measurements were compared with the dietary reference intake for healthy children and adults (D-A-CH dietary recommendations), US and German CF recommendations, and serum retinol concentrations from National Health and Nutrition Examination Survey (NHANES) data.
  
  
  RESULTS
  Total vitamin A intake from food and supplementation was 315% ± 182% of D-A-CH recommendations, with 65% from supplements. The range of the prescribed vitamin A supplementation dosage was 0-20,000 IU/day (median 5500 IU), and it was consistent with CF recommendations in 28% of participants. A quarter of all patients did not need any vitamin A supplementation. The total vitamin A intake exceeded the recommended upper limit of intake in 69% of subjects. The mean (range) serum retinol was 38.6 μg/dl (22.1-59.1 μg/dl). All subjects had serum retinol levels above 20 μg/dl and below 72 μg/dl (95th percentile of NHANES reference range).
  
  
  CONCLUSIONS
  Individualized vitamin A supplementation of 0-20,000 IU/day based on annual serum retinol measurements may prevent deficiency and high serum retinol levels, but it may lead to vitamin A intake above the tolerable upper intake level.
authors: Institute of Nutritional Sciences, Justus-Liebig-University Giessen, Wilhelmstrasse 20, D-35392 Giessen, Germany.
authors: Christina
authors: C
authors: Brei
authors: Annette
authors: A
authors: Simon
authors: Michael B
authors: MB
authors: Krawinkel
authors: Lutz
authors: L
authors: Naehrlich
mesh_terms: D000293:Adolescent; D000328:Adult; D000402:Airway Obstruction / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000097:blood / Q000178:diet therapy* / Q000503:physiopathology; D004032:Diet / Q000009:adverse effects; D019587:Dietary Supplements / Q000009:adverse effects; D010188:Exocrine Pancreatic Insufficiency / Q000209:etiology; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D006986:Hypervitaminosis A / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D008168:Lung / Q000503:physiopathology; D008297:Male; D046790:Pancreas, Exocrine / Q000503:physiopathology; D057285:Precision Medicine; D064167:Recommended Dietary Allowances; D012720:Severity of Illness Index; D014801:Vitamin A / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use; D014802:Vitamin A Deficiency / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D055815:Young Adult
chemical_list: D014801:Vitamin A
keywords: Cystic fibrosis; Dietary supplements; D–A–CH recommendations; FEV1%pred; NHANES; National Health and Nutrition Examination Survey; UL; Vitamin A; dietary recommendations from the D–A–CH countries (Germany (D), Austria (A), and Switzerland (CH)); percent predicted of forced expiratory volume in 1 s; upper limit of intake