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Clinical nutrition, enteral and parenteral nutrition

Unrestricted consumption of fruits and vegetables in phenylketonuria: no major impact on metabolic control

European Journal of Clinical Nutrition volume 66, pages 633–638 (2012)Cite this article

Subjects

Abstract

Background/Objectives:

The treatment of phenylketonuria (PKU) requires consistent restriction of protein intake from natural sources. Therefore, protein from all foods has to be accounted for, even the small amounts in fruits and vegetables. We studied whether free consumption of fruits and vegetables containing less than 75 mg phenylalanine (phe) per 100 g affects metabolic control in children with PKU.

Subjects/Methods:

Fourteen children (2–10 years) were included in a cross-over study, with a two-week period of conventional treatment (accounting for protein from fruits and vegetables) and a two-week period with free fruit and vegetable consumption. The instruction to follow liberal fruit and vegetable consumption in the first or second study period was randomized. Detailed daily dietary records were obtained throughout the study. Phe and nutrient content was calculated. Dried-blood phe concentration was monitored daily.

Results:

Although total phe intake increased by an average of 58 mg per day (P=0.037) during the 2 weeks of free fruit and vegetable consumption, dried-blood phe concentrations were unchanged. Total intake of fruits and vegetables did not increase, but patients instead used the higher phe tolerance to consume more of other foods, which were calculated and accounted for.

Conclusion:

Free consumption of fruits and vegetables does not impair metabolic control in PKU patients over a 2-week period.

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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 for Inborn Metabolic Diseases, University Hospital for Children and Adolescents, University of Leipzig, Leipzig, Germany

    C Rohde, U Mütze, J F W Weigel, W Kiess & S Beblo

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

    U Ceglarek & J Thiery

Authors
  1. C Rohde
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  2. U Mütze
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  3. J F W Weigel
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  4. U Ceglarek
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  6. W Kiess
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  7. S Beblo
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Corresponding author

Correspondence to S Beblo.

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The authors declare no conflict of interest.

Additional information

Contributors: The trial was designed and submitted to the authorities by SB and CR, with substantial consultation by WK and UC; patients were recruited and examined, and samples taken by SB, UM and JFWW; blood samples were analysed by UC and JT; dietary reports were analysed by CR; data management was maintained by CR and SB; statistical analyses were performed by SB; results were discussed and conclusions drawn by all contributing authors; CR and SB drafted the manuscript and incorporated comments by all co-authors.

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Rohde, C., Mütze, U., Weigel, J. et al. Unrestricted consumption of fruits and vegetables in phenylketonuria: no major impact on metabolic control. Eur J Clin Nutr 66, 633–638 (2012). https://doi.org/10.1038/ejcn.2011.205

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