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Unrestricted fruits and vegetables in the PKU diet: a 1-year follow-up

European Journal of Clinical Nutrition volume 68, pages 401–403 (2014)Cite this article

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Abstract

Phenylketonuria (PKU) therapy demands phenylalanine (Phe) calculation. In most countries, almost all food is taken into account, even fruits and vegetables. We investigated whether unrestricted consumption of fruits and vegetables negatively influences metabolic control. Nineteen PKU children (2–10 years) started with 2 weeks of free or restricted fruit and vegetable intake. After 2 weeks, the regime changed from free to restricted or restricted to free (cross-over design). Over the first 4 weeks, dried blood Phe concentration was measured, fruit and vegetable consumption recorded and nutrient intake calculated from diet records. Thereafter the diet was changed to free use of fruits and vegetables for all patients. Six and 12 months later, diet and Phe concentrations were monitored. Median Phe intake increased significantly by 65 mg/day (week 4, P<0.001), 68 mg/day (month 6, P<0.001) and 70 mg/day (month 12, P<0.001). Dried blood Phe concentrations remained stable (P=0.894), as did the frequency of Phe concentrations above the recommended range (P=0.592). In conclusion, PKU diet liberalization for fruits and vegetables seems unproblematic.

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Acknowledgements

We thank the patients and their parents for their participation and daily efforts to meet the protocol requirements. The unrestricted financial support by MetaX, Institut für Diätetik, is greatly appreciated. Dr Gelbrich provided valuable advice concerning biometry and statistical analysis.

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Authors and Affiliations

  1. Department of Women and Child Health, Hospital for Children and Adolescents, Centre of Paediatric Research (CPR), University Hospitals, University of Leipzig, Germany

    C Rohde, U Mütze, A G Thiele, W Kiess & S Beblo

  2. Center for Obstetrics and Paediatrics, University Medical Center Hamburg-Eppendorf, Hamburg-Eppendorf, Germany

    S Schulz

  3. Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University of Leipzig, Germany

    U Ceglarek & J Thiery

  4. Institute of Agricultural and Nutritional Sciences, Martin-Luther-University Halle-Wittenberg, Germany

    A S Mueller

Authors
  1. C Rohde
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  2. U Mütze
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  3. S Schulz
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  4. A G Thiele
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  5. U Ceglarek
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  6. J Thiery
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  7. A S Mueller
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  8. W Kiess
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  9. S Beblo
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Correspondence to S Beblo.

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The authors declare no conflict of interest.

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Author contributions

The trial was designed and submitted to authorities by SB and CR, with substantial consultation by WK and UC; patients were recruited and examined, and samples taken by SB, UM and MA; blood samples were analyzed by UC and JT; diet records were analyzed by CR; data management was maintained by CR and SB; statistical analyses were performed by CR; results were discussed and conclusions drawn by all contributing authors, especially ASM, AGT and UM; CR and SB drafted the manuscript and incorporated comments by all co-authors.

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Rohde, C., Mütze, U., Schulz, S. et al. Unrestricted fruits and vegetables in the PKU diet: a 1-year follow-up. Eur J Clin Nutr 68, 401–403 (2014). https://doi.org/10.1038/ejcn.2013.272

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  • DOI: https://doi.org/10.1038/ejcn.2013.272

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