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Diurnal variations in blood phenylalanine of PKU infants under different feeding regimes

Margreet van Rijn1, Marieke Hoeksma, Pieter J J Sauer

  • 1Department of Pediatrics, Section of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center of Groningen, University of Groningen, The Netherlands. m.van.rijn@umcg.nl

Molecular Genetics and Metabolism
|October 11, 2011
PubMed

Insights

Diurnal blood phenylalanine (Phe) fluctuations in infants with phenylketonuria (PKU) are similar whether natural protein and Phe-free formula are combined or alternated. This finding is crucial for managing PKU in infants under one year old.

Area of Science:

  • Biochemistry
  • Pediatrics
  • Metabolic Disorders

Background:

  • Phenylketonuria (PKU) is a metabolic disorder characterized by elevated blood phenylalanine (Phe) levels.
  • Diurnal Phe fluctuations in PKU patients differ from healthy individuals.
  • Previous studies on diurnal Phe patterns focused on PKU patients over one year of age.

Purpose of the Study:

  • To investigate diurnal patterns of blood phenylalanine (Phe) concentrations in infants with PKU under one year of age.
  • To compare two infant feeding schemes: combined natural protein and Phe-free formula, versus alternating feeds.
  • To assess the impact of feeding strategies on Phe level variability in early PKU management.

Main Methods:

  • An observational study involving 7 PKU infants aged 3-8 months.
  • Blood Phe concentrations were measured before each feeding on two separate days.
  • Day A: infants received combined natural protein and Phe-free formula per feeding.
  • Day B: infants received natural protein and Phe-free formula in an alternating feeding schedule.
  • Total protein, energy intake, and feeding frequency were consistent across study days.

Main Results:

  • Mean differences between minimum and maximum blood Phe concentrations were comparable on both days (81±50 μmol/L on Day A vs. 104±26 μmol/L on Day B).
  • A significant percentage of samples were within the target range (<120 μmol/L) on both days (50% Day A, 30% Day B).
  • Very few samples exceeded the upper target range (>360 μmol/L) (3% Day A, 6% Day B).

Conclusions:

  • Both feeding regimens (combined or alternating) yield similar diurnal fluctuations in blood Phe levels for PKU infants.
  • These findings suggest flexibility in feeding strategies for managing Phe levels in infants with PKU.
  • The study provides insights into early nutritional management of PKU in infants.
Abstract

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