title: No improvement in suboptimal vitamin A status with a randomized, double-blind, placebo-controlled trial of vitamin A supplementation in children with sickle cell disease.
abstract: BACKGROUND
  Suboptimal vitamin A status is prevalent in children with type SS sickle cell disease (SCD-SS) and is associated with hospitalizations and poor growth and hematologic status. The supplemental vitamin A dose that optimizes suboptimal vitamin A status in this population is unknown.
  
  
  OBJECTIVE
  The efficacy of Recommended Dietary Allowance (RDA) doses (based on age and sex) of vitamin A (300, 400, or 600 μg retinyl palmitate/d) or vitamin A + zinc (10 or 20 mg zinc sulfate/d) compared with placebo to optimize vitamin A status was assessed in children aged 2.0-12.9 y with SCD-SS and a suboptimal baseline serum retinol concentration (<30 μg/dL).
  
  
  METHODS
  In this randomized, double-blind, placebo-controlled trial, vitamin A status (serum retinol, prealbumin, retinol-binding protein, and relative-dose-response test) and disease-related illness events were assessed.
  
  
  RESULTS
  Twelve months of vitamin A supplementation at the doses recommended for healthy US children (based on age and sex) failed to improve serum retinol values in either group (vitamin A: n = 23; vitamin A + zinc: n = 18) compared with placebo (n = 21). By 12 mo, the increase (±SD) in serum retinol (3.6 ± 2.8 μg/dL) in those taking 600 μg vitamin A/d was significantly different from the decrease (±SD; -2.8 ± 2.4 μg/dL) in those taking 300 μg/d, which possibly suggests a dose-response relation (P < 0.05) with RDA doses.
  
  
  CONCLUSIONS
  Compared with placebo, 12 mo of vitamin A supplementation at the RDA for healthy children did not improve serum retinol values in children with SCD-SS, which possibly suggests that higher doses are needed. However, the existence of alternative conclusions emphasizes the need for future research.
authors.affiliation: Divisions of Gastroenterology, Hepatology and Nutrition and Hematology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA. doughertyk@email.chop.edu
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Dougherty
authors.forename: Joan I
authors.initials: JI
authors.lastname: Schall
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Kawchak
authors.forename: Michael H
authors.initials: MH
authors.lastname: Green
authors.forename: Kwaku
authors.initials: K
authors.lastname: Ohene-Frempong
authors.forename: Babette S
authors.initials: BS
authors.lastname: Zemel
authors.forename: Virginia A
authors.initials: VA
authors.lastname: Stallings
mesh_terms: D000755:Anemia, Sickle Cell / Q000097:blood / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D019587:Dietary Supplements; D004224:Diterpenes; D004311:Double-Blind Method; D005260:Female; D006451:Hemoglobin, Sickle / Q000235:genetics / Q000378:metabolism; D006720:Homozygote; D006801:Humans; D008297:Male; D009751:Nutritional Requirements; D009752:Nutritional Status; D010865:Pilot Projects; D015995:Prevalence; D000084562:Retinyl Esters; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology; D014801:Vitamin A / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000627:therapeutic use*; D014802:Vitamin A Deficiency / Q000188:drug therapy* / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D019287:Zinc Sulfate / Q000008:administration & dosage / Q000627:therapeutic use
chemical_list: D004224:Diterpenes; D006451:Hemoglobin, Sickle; D000084562:Retinyl Esters; D014801:Vitamin A; C014794:retinol palmitate; D019287:Zinc Sulfate