title: [High plasma folate in patients with phenylketonuria].
abstract: Phenylketonuria is an inborn error of metabolism treated with a closely monitored low phenylalanine diet. Protein substitutes used for treatment are supplemented with vitamins and micronutrients.
  
  
  OBJECTIVE
  The aim of this study was to investigate plasma folic acid concentrations in children with phenylketonuria.
  
  
  METHODS
  Retrospective analysis of medical records of 73 patients with phenylketonuria and 28 with mild hyperphenylalaninemia (on normal diet) was carried out. Intake of folic acid was calculated on the basis of protein substitute intake. Folate concentrations were analyzed according to their intake, and concentration of homocysteine and phenylalanine.
  
  
  RESULTS
  In 76.7% patients with phenylketonuria intake of folic acid exceeded recommended dietary allowance. Serum folic acid concentrations above upper reference level were detected in 75.3% patients with phenylketonuria and only in 25% patients with hyperphenylalaninemia (p<0.0001). Strong positive correlation between daily intake of folic acid (with protein substitute) and concentration plasma folic acid (corr=0.55, p<0.0001) has been observed.
  
  
  CONCLUSIONS
  Low phenylalanine diet using protein substitutes currently available in Poland predisposes to high concentration of plasma folic acid. The security of folic acid hipersupplementation in patients with phenylketonuria requires further detailed research.
authors.affiliation: Institute of Mother and Child in Warsaw, Poland: Department of Pediatry.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Zielińska
authors.affiliation: Institute of Mother and Child in Warsaw, Poland: Out-patient Department of Metabolic Diseases.
authors.forename: Joanna
authors.initials: J
authors.lastname: Żółkowska
authors.affiliation: Institute of Mother and Child in Warsaw, Poland: Department of Pediatry.
authors.forename: Amanda
authors.initials: A
authors.lastname: Przybylska-Kruszewska
authors.affiliation: Institute of Mother and Child in Warsaw, Poland: Department of Pediatry.
authors.forename: Dominika
authors.initials: D
authors.lastname: Gładysz
authors.affiliation: Institute of Mother and Child in Warsaw, Poland: Out-patient Department of Metabolic Diseases.
authors.forename: Dorota
authors.initials: D
authors.lastname: Korycińska-Chaaban
authors.affiliation: Institute of Mother and Child in Warsaw, Poland: Department of Pediatry; Out-patient Department of Metabolic Diseases.
authors.forename: Maria
authors.initials: M
authors.lastname: Nowacka
authors.affiliation: Institute of Mother and Child in Warsaw, Poland: Department of Pediatry.
authors.forename: Kamil K
authors.initials: KK
authors.lastname: Hozyasz
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D005492:Folic Acid / Q000097:blood*; D006801:Humans; D008297:Male; D010661:Phenylketonurias / Q000097:blood* / Q000178:diet therapy; D011044:Poland; D012189:Retrospective Studies
chemical_list: D005492:Folic Acid
keywords: diet; folic acid; hyperphenylalaninemia; phenylketonuria