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Over Restriction of Dietary Protein Allowance: The Importance of Ongoing Reassessment of Natural Protein Tolerance in Phenylketonuria

Phenylalanine (Phe) tolerance is highly variable in phenylketonuria (PKU) and rarely described in patients aged ≥12 years. Patients ≥12 years of age with PKU were systematically challenged with additional natural protein (NP) if blood Phe levels remained below 480 µmol/L (i.e., upper target blood Ph...

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Autores principales: Pinto, Alex, Ferreira Almeida, Manuela, MacDonald, Anita, Cristina Ramos, Paula, Rocha, Sara, Guimas, Arlindo, Ribeiro, Rosa, Martins, Esmeralda, Bandeira, Anabela, Jackson, Richard, van Spronsen, Francjan, Payne, Anne, César Rocha, Júlio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6566391/
https://www.ncbi.nlm.nih.gov/pubmed/31052331
http://dx.doi.org/10.3390/nu11050995
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author Pinto, Alex
Ferreira Almeida, Manuela
MacDonald, Anita
Cristina Ramos, Paula
Rocha, Sara
Guimas, Arlindo
Ribeiro, Rosa
Martins, Esmeralda
Bandeira, Anabela
Jackson, Richard
van Spronsen, Francjan
Payne, Anne
César Rocha, Júlio
author_facet Pinto, Alex
Ferreira Almeida, Manuela
MacDonald, Anita
Cristina Ramos, Paula
Rocha, Sara
Guimas, Arlindo
Ribeiro, Rosa
Martins, Esmeralda
Bandeira, Anabela
Jackson, Richard
van Spronsen, Francjan
Payne, Anne
César Rocha, Júlio
author_sort Pinto, Alex
collection PubMed
description Phenylalanine (Phe) tolerance is highly variable in phenylketonuria (PKU) and rarely described in patients aged ≥12 years. Patients ≥12 years of age with PKU were systematically challenged with additional natural protein (NP) if blood Phe levels remained below 480 µmol/L (i.e., upper target blood Phe level for patients aged ≥12 years using Portuguese PKU guidelines). In PKU patients, NP tolerance was calculated at baseline and a median of 6 months after systematic challenge with NP whilst patients were maintaining a blood Phe ≤480 μmol/L. Anthropometry was assessed at both times. Routine blood Phe levels were collected. We studied 40 well-controlled PKU patients (10 hyperphenylalaninemia (HPA), 23 mild and 7 classic PKU), on a low-Phe diet with a mean age of 17 years (12–29 years). Median daily NP intake significantly increased between assessments (35 vs. 40 g/day, p = 0.01). Twenty-six patients (65%) were able to increase their median NP intake by a median 12 g/day (2–42 g)/day and still maintain blood Phe within target range. Out of the previous 26 patients, 20 (77%) (8 HPA, 11 mild and 1 classical PKU) increased NP from animal sources (e.g., dairy products, fish and meat) and 6 patients (23%) (3 mild and 3 classical PKU) from plant foods (bread, pasta, potatoes). Median protein equivalent intake from Phe-free/low-Phe protein substitute decreased (0.82 vs. 0.75 g/kg, p = 0.01), while median blood Phe levels remained unchanged (279 vs. 288 μmol/L, p = 0.06). Almost two-thirds of patients with PKU tolerated additional NP when challenged and still maintained blood Phe within the national target range. This suggests that some patients with PKU treated by a low-Phe diet only may over restrict their NP intake. In order to minimise the burden of treatment and optimise NP intake, it is important to challenge with additional NP at periodic intervals.
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spelling pubmed-65663912019-06-17 Over Restriction of Dietary Protein Allowance: The Importance of Ongoing Reassessment of Natural Protein Tolerance in Phenylketonuria Pinto, Alex Ferreira Almeida, Manuela MacDonald, Anita Cristina Ramos, Paula Rocha, Sara Guimas, Arlindo Ribeiro, Rosa Martins, Esmeralda Bandeira, Anabela Jackson, Richard van Spronsen, Francjan Payne, Anne César Rocha, Júlio Nutrients Article Phenylalanine (Phe) tolerance is highly variable in phenylketonuria (PKU) and rarely described in patients aged ≥12 years. Patients ≥12 years of age with PKU were systematically challenged with additional natural protein (NP) if blood Phe levels remained below 480 µmol/L (i.e., upper target blood Phe level for patients aged ≥12 years using Portuguese PKU guidelines). In PKU patients, NP tolerance was calculated at baseline and a median of 6 months after systematic challenge with NP whilst patients were maintaining a blood Phe ≤480 μmol/L. Anthropometry was assessed at both times. Routine blood Phe levels were collected. We studied 40 well-controlled PKU patients (10 hyperphenylalaninemia (HPA), 23 mild and 7 classic PKU), on a low-Phe diet with a mean age of 17 years (12–29 years). Median daily NP intake significantly increased between assessments (35 vs. 40 g/day, p = 0.01). Twenty-six patients (65%) were able to increase their median NP intake by a median 12 g/day (2–42 g)/day and still maintain blood Phe within target range. Out of the previous 26 patients, 20 (77%) (8 HPA, 11 mild and 1 classical PKU) increased NP from animal sources (e.g., dairy products, fish and meat) and 6 patients (23%) (3 mild and 3 classical PKU) from plant foods (bread, pasta, potatoes). Median protein equivalent intake from Phe-free/low-Phe protein substitute decreased (0.82 vs. 0.75 g/kg, p = 0.01), while median blood Phe levels remained unchanged (279 vs. 288 μmol/L, p = 0.06). Almost two-thirds of patients with PKU tolerated additional NP when challenged and still maintained blood Phe within the national target range. This suggests that some patients with PKU treated by a low-Phe diet only may over restrict their NP intake. In order to minimise the burden of treatment and optimise NP intake, it is important to challenge with additional NP at periodic intervals. MDPI 2019-04-30 /pmc/articles/PMC6566391/ /pubmed/31052331 http://dx.doi.org/10.3390/nu11050995 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Pinto, Alex
Ferreira Almeida, Manuela
MacDonald, Anita
Cristina Ramos, Paula
Rocha, Sara
Guimas, Arlindo
Ribeiro, Rosa
Martins, Esmeralda
Bandeira, Anabela
Jackson, Richard
van Spronsen, Francjan
Payne, Anne
César Rocha, Júlio
Over Restriction of Dietary Protein Allowance: The Importance of Ongoing Reassessment of Natural Protein Tolerance in Phenylketonuria
title Over Restriction of Dietary Protein Allowance: The Importance of Ongoing Reassessment of Natural Protein Tolerance in Phenylketonuria
title_full Over Restriction of Dietary Protein Allowance: The Importance of Ongoing Reassessment of Natural Protein Tolerance in Phenylketonuria
title_fullStr Over Restriction of Dietary Protein Allowance: The Importance of Ongoing Reassessment of Natural Protein Tolerance in Phenylketonuria
title_full_unstemmed Over Restriction of Dietary Protein Allowance: The Importance of Ongoing Reassessment of Natural Protein Tolerance in Phenylketonuria
title_short Over Restriction of Dietary Protein Allowance: The Importance of Ongoing Reassessment of Natural Protein Tolerance in Phenylketonuria
title_sort over restriction of dietary protein allowance: the importance of ongoing reassessment of natural protein tolerance in phenylketonuria
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6566391/
https://www.ncbi.nlm.nih.gov/pubmed/31052331
http://dx.doi.org/10.3390/nu11050995
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