Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis

The traditional treatment for phenylketonuria (PKU) is a phenylalanine (Phe)-restricted diet, supplemented with a Phe-free/low-Phe protein substitute. Pharmaceutical treatment with synthetic tetrahydrobiopterin (BH4), an enzyme cofactor, allows a patient subgroup to relax their diet. However, dietar...

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Main Authors: Fatma Ilgaz, Cyril Marsaux, Alex Pinto, Rani Singh, Carmen Rohde, Erdem Karabulut, Hülya Gökmen-Özel, Mirjam Kuhn, Anita MacDonald
Format: Article
Language:English
Published: MDPI AG 2021-03-01
Series:Nutrients
Subjects:
Online Access:https://www.mdpi.com/2072-6643/13/3/1040
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author Fatma Ilgaz
Cyril Marsaux
Alex Pinto
Rani Singh
Carmen Rohde
Erdem Karabulut
Hülya Gökmen-Özel
Mirjam Kuhn
Anita MacDonald
author_facet Fatma Ilgaz
Cyril Marsaux
Alex Pinto
Rani Singh
Carmen Rohde
Erdem Karabulut
Hülya Gökmen-Özel
Mirjam Kuhn
Anita MacDonald
author_sort Fatma Ilgaz
collection DOAJ
description The traditional treatment for phenylketonuria (PKU) is a phenylalanine (Phe)-restricted diet, supplemented with a Phe-free/low-Phe protein substitute. Pharmaceutical treatment with synthetic tetrahydrobiopterin (BH4), an enzyme cofactor, allows a patient subgroup to relax their diet. However, dietary protocols guiding the adjustments of protein equivalent intake from protein substitute with BH4 treatment are lacking. We systematically reviewed protein substitute usage with long-term BH4 therapy. Electronic databases were searched for articles published between January 2000 and March 2020. Eighteen studies (306 PKU patients) were eligible. Meta-analyses demonstrated a significant increase in Phe and natural protein intakes and a significant decrease in protein equivalent intake from protein substitute with cofactor therapy. Protein substitute could be discontinued in 51% of responsive patients, but was still required in 49%, despite improvement in Phe tolerance. Normal growth was maintained, but micronutrient deficiency was observed with BH4 treatment. A systematic protocol to increase natural protein intake while reducing protein substitute dose should be followed to ensure protein and micronutrient requirements are met and sustained. We propose recommendations to guide healthcare professionals when adjusting dietary prescriptions of PKU patients on BH4. Studies investigating new therapeutic options in PKU should systematically collect data on protein substitute and natural protein intakes, as well as other nutritional factors.
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spelling doaj.art-69b7b06de18e4a24a7bab4ffa9fe1a8e2023-11-21T11:44:12ZengMDPI AGNutrients2072-66432021-03-01133104010.3390/nu13031040Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-AnalysisFatma Ilgaz0Cyril Marsaux1Alex Pinto2Rani Singh3Carmen Rohde4Erdem Karabulut5Hülya Gökmen-Özel6Mirjam Kuhn7Anita MacDonald8Department of Nutrition and Dietetics, Faculty of Health Sciences, Hacettepe University, 06100 Ankara, TurkeyDanone Nutricia Research, 3584CT Utrecht, The NetherlandsDepartment of Dietetics, Birmingham Women’s and Children’s Hospital, Birmingham B4 6NH, UKMetabolic Genetics Nutrition Program, Department of Human Genetics, Emory University, Atlanta, GA 30322, USADepartment of Paediatrics of the University Clinics Leipzig, University of Leipzig, 04103 Leipzig, GermanyDepartment of Biostatistics, Faculty of Medicine, Hacettepe University, 06100 Ankara, TurkeyDepartment of Nutrition and Dietetics, Faculty of Health Sciences, Hacettepe University, 06100 Ankara, TurkeyDanone Nutricia Research, 3584CT Utrecht, The NetherlandsDepartment of Dietetics, Birmingham Women’s and Children’s Hospital, Birmingham B4 6NH, UKThe traditional treatment for phenylketonuria (PKU) is a phenylalanine (Phe)-restricted diet, supplemented with a Phe-free/low-Phe protein substitute. Pharmaceutical treatment with synthetic tetrahydrobiopterin (BH4), an enzyme cofactor, allows a patient subgroup to relax their diet. However, dietary protocols guiding the adjustments of protein equivalent intake from protein substitute with BH4 treatment are lacking. We systematically reviewed protein substitute usage with long-term BH4 therapy. Electronic databases were searched for articles published between January 2000 and March 2020. Eighteen studies (306 PKU patients) were eligible. Meta-analyses demonstrated a significant increase in Phe and natural protein intakes and a significant decrease in protein equivalent intake from protein substitute with cofactor therapy. Protein substitute could be discontinued in 51% of responsive patients, but was still required in 49%, despite improvement in Phe tolerance. Normal growth was maintained, but micronutrient deficiency was observed with BH4 treatment. A systematic protocol to increase natural protein intake while reducing protein substitute dose should be followed to ensure protein and micronutrient requirements are met and sustained. We propose recommendations to guide healthcare professionals when adjusting dietary prescriptions of PKU patients on BH4. Studies investigating new therapeutic options in PKU should systematically collect data on protein substitute and natural protein intakes, as well as other nutritional factors.https://www.mdpi.com/2072-6643/13/3/1040phenylalanine hydroxylase deficiencyhyperphenylalaninemiaPKUprotein substitutemedical formulaamino acid mixture
spellingShingle Fatma Ilgaz
Cyril Marsaux
Alex Pinto
Rani Singh
Carmen Rohde
Erdem Karabulut
Hülya Gökmen-Özel
Mirjam Kuhn
Anita MacDonald
Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis
Nutrients
phenylalanine hydroxylase deficiency
hyperphenylalaninemia
PKU
protein substitute
medical formula
amino acid mixture
title Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis
title_full Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis
title_fullStr Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis
title_full_unstemmed Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis
title_short Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis
title_sort protein substitute requirements of patients with phenylketonuria on bh4 treatment a systematic review and meta analysis
topic phenylalanine hydroxylase deficiency
hyperphenylalaninemia
PKU
protein substitute
medical formula
amino acid mixture
url https://www.mdpi.com/2072-6643/13/3/1040
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