The Effect of Glycomacropeptide versus Amino Acids on Phenylalanine and Tyrosine Variability over 24 Hours in Children with PKU: A Randomized Controlled Trial

<b>Introduction:</b> In phenylketonuria (PKU), evidence suggests that casein glycomacropeptide supplemented with rate-limiting amino acids (CGMP-AA) is associated with better protein utilisation and less blood phenylalanine (Phe) variability. <b>Aim:</b> To study the impact o...

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Main Authors: Anne Daly, Sharon Evans, Satnam Chahal, Saikat Santra, Alex Pinto, Cerys Gingell, Júlio César Rocha, Francjan van Spronsen, Richard Jackson, Anita MacDonald
Format: Article
Language:English
Published: MDPI AG 2019-02-01
Series:Nutrients
Subjects:
Online Access:https://www.mdpi.com/2072-6643/11/3/520
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author Anne Daly
Sharon Evans
Satnam Chahal
Saikat Santra
Alex Pinto
Cerys Gingell
Júlio César Rocha
Francjan van Spronsen
Richard Jackson
Anita MacDonald
author_facet Anne Daly
Sharon Evans
Satnam Chahal
Saikat Santra
Alex Pinto
Cerys Gingell
Júlio César Rocha
Francjan van Spronsen
Richard Jackson
Anita MacDonald
author_sort Anne Daly
collection DOAJ
description <b>Introduction:</b> In phenylketonuria (PKU), evidence suggests that casein glycomacropeptide supplemented with rate-limiting amino acids (CGMP-AA) is associated with better protein utilisation and less blood phenylalanine (Phe) variability. <b>Aim:</b> To study the impact of CGMP-AA on blood Phe variability using 3 different dietary regimens in children with PKU. <b>Methods:</b> This was a 6-week randomised controlled cross-over study comparing CGMP-AA vs. Phe-free <span style="font-variant: small-caps;">l</span>-amino acids (<span style="font-variant: small-caps;">l</span>-AA) assessing blood Phe and tyrosine (Tyr) variability over 24 h in 19 children (7 boys) with PKU, with a median age of 10 years (6&#8315;16). Subjects were randomised to 3 dietary regimens: (1) R1, CGMP-AA and usual dietary Phe (CGMP + Phe); (2) R2, CGMP-AA &#8722; Phe content of CGMP-AA from usual diet (CGMP &#8722; Phe); and (3) R3, <span style="font-variant: small-caps;">l</span>-AA and usual dietary Phe. Each regimen was administered for 14 days. Over the last 48 h on days 13 and 14, blood spots were collected every 4 h at 08 h, 12 h, 16 h, 20 h, 24 h, and 04 h. Isocaloric intake and the same meal plan and protein substitute dosage at standardised times were maintained when blood spots were collected. <b>Results:</b> Eighteen children completed the study. Median Phe concentrations over 24 h for each group were (range) R1, 290 (30&#8315;580), R2, 220 (10&#8315;670), R3, 165 (10&#8315;640) &#956;mol/L. R1 vs. R2 and R1 vs. R3 <i>p</i> &lt; 0.0001; R2 vs. R3 <i>p</i> = 0.0009. There was a significant difference in median Phe at each time point between R1 vs. R2, <i>p</i> = 0.0027 and R1 vs. R3, <i>p</i> &lt; 0.0001, but not between any time points for R2 vs. R3. Tyr was significantly higher in both R1 and R2 [70 (20&#8315;240 &#956;mol/L] compared to R3 [60 (10&#8315;200) &#956;mol/L]. In children &lt; 12 years, blood Phe remained in the target range (120&#8315;360 &#956;mol/L), over 24 h, for 75% of the time in R1, 72% in R2 and 64% in R3; for children aged &#8805; 12 years, blood Phe was in target range (120&#8315;600 &#956;mol/L) in R1 and R2 for 100% of the time, but 64% in R3. <b>Conclusions:</b> The residual Phe in CGMP-AA increased blood Phe concentration in children. CGMP-AA appears to give less blood Phe variability compared to <span style="font-variant: small-caps;">l</span>-AA, but this effect may be masked by the increased blood Phe concentrations associated with its Phe contribution. Reducing dietary Phe intake to compensate for CGMP-AA Phe content may help.
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spelling doaj.art-da00a761021644ad90af5c57b62ece1b2022-12-22T03:41:45ZengMDPI AGNutrients2072-66432019-02-0111352010.3390/nu11030520nu11030520The Effect of Glycomacropeptide versus Amino Acids on Phenylalanine and Tyrosine Variability over 24 Hours in Children with PKU: A Randomized Controlled TrialAnne Daly0Sharon Evans1Satnam Chahal2Saikat Santra3Alex Pinto4Cerys Gingell5Júlio César Rocha6Francjan van Spronsen7Richard Jackson8Anita MacDonald9Birmingham Women’s and Children’s Hospital, Steelhouse Lane, Birmingham B4 6 NH, UKBirmingham Women’s and Children’s Hospital, Steelhouse Lane, Birmingham B4 6 NH, UKBirmingham Women’s and Children’s Hospital, Steelhouse Lane, Birmingham B4 6 NH, UKBirmingham Women’s and Children’s Hospital, Steelhouse Lane, Birmingham B4 6 NH, UKBirmingham Women’s and Children’s Hospital, Steelhouse Lane, Birmingham B4 6 NH, UKNottingham Queen’s Medical Centre, University Hospital, Derby Road, Nottingham NG7 2UH, UKCentro de Genética Médica, Centro Hospitalar Universitário do Porto (CHUP), 4099-028 Porto, PortugalBeatrix Children’s Hospital, University Medical Centre of Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The NetherlandsLiverpool University, Brownlow Hill, Liverpool L69 7ZX, UKBirmingham Women’s and Children’s Hospital, Steelhouse Lane, Birmingham B4 6 NH, UK<b>Introduction:</b> In phenylketonuria (PKU), evidence suggests that casein glycomacropeptide supplemented with rate-limiting amino acids (CGMP-AA) is associated with better protein utilisation and less blood phenylalanine (Phe) variability. <b>Aim:</b> To study the impact of CGMP-AA on blood Phe variability using 3 different dietary regimens in children with PKU. <b>Methods:</b> This was a 6-week randomised controlled cross-over study comparing CGMP-AA vs. Phe-free <span style="font-variant: small-caps;">l</span>-amino acids (<span style="font-variant: small-caps;">l</span>-AA) assessing blood Phe and tyrosine (Tyr) variability over 24 h in 19 children (7 boys) with PKU, with a median age of 10 years (6&#8315;16). Subjects were randomised to 3 dietary regimens: (1) R1, CGMP-AA and usual dietary Phe (CGMP + Phe); (2) R2, CGMP-AA &#8722; Phe content of CGMP-AA from usual diet (CGMP &#8722; Phe); and (3) R3, <span style="font-variant: small-caps;">l</span>-AA and usual dietary Phe. Each regimen was administered for 14 days. Over the last 48 h on days 13 and 14, blood spots were collected every 4 h at 08 h, 12 h, 16 h, 20 h, 24 h, and 04 h. Isocaloric intake and the same meal plan and protein substitute dosage at standardised times were maintained when blood spots were collected. <b>Results:</b> Eighteen children completed the study. Median Phe concentrations over 24 h for each group were (range) R1, 290 (30&#8315;580), R2, 220 (10&#8315;670), R3, 165 (10&#8315;640) &#956;mol/L. R1 vs. R2 and R1 vs. R3 <i>p</i> &lt; 0.0001; R2 vs. R3 <i>p</i> = 0.0009. There was a significant difference in median Phe at each time point between R1 vs. R2, <i>p</i> = 0.0027 and R1 vs. R3, <i>p</i> &lt; 0.0001, but not between any time points for R2 vs. R3. Tyr was significantly higher in both R1 and R2 [70 (20&#8315;240 &#956;mol/L] compared to R3 [60 (10&#8315;200) &#956;mol/L]. In children &lt; 12 years, blood Phe remained in the target range (120&#8315;360 &#956;mol/L), over 24 h, for 75% of the time in R1, 72% in R2 and 64% in R3; for children aged &#8805; 12 years, blood Phe was in target range (120&#8315;600 &#956;mol/L) in R1 and R2 for 100% of the time, but 64% in R3. <b>Conclusions:</b> The residual Phe in CGMP-AA increased blood Phe concentration in children. CGMP-AA appears to give less blood Phe variability compared to <span style="font-variant: small-caps;">l</span>-AA, but this effect may be masked by the increased blood Phe concentrations associated with its Phe contribution. Reducing dietary Phe intake to compensate for CGMP-AA Phe content may help.https://www.mdpi.com/2072-6643/11/3/520glycomacropeptidephenylalaninephenylketonuriaphenylalanine variabilityamino acidstyrosine
spellingShingle Anne Daly
Sharon Evans
Satnam Chahal
Saikat Santra
Alex Pinto
Cerys Gingell
Júlio César Rocha
Francjan van Spronsen
Richard Jackson
Anita MacDonald
The Effect of Glycomacropeptide versus Amino Acids on Phenylalanine and Tyrosine Variability over 24 Hours in Children with PKU: A Randomized Controlled Trial
Nutrients
glycomacropeptide
phenylalanine
phenylketonuria
phenylalanine variability
amino acids
tyrosine
title The Effect of Glycomacropeptide versus Amino Acids on Phenylalanine and Tyrosine Variability over 24 Hours in Children with PKU: A Randomized Controlled Trial
title_full The Effect of Glycomacropeptide versus Amino Acids on Phenylalanine and Tyrosine Variability over 24 Hours in Children with PKU: A Randomized Controlled Trial
title_fullStr The Effect of Glycomacropeptide versus Amino Acids on Phenylalanine and Tyrosine Variability over 24 Hours in Children with PKU: A Randomized Controlled Trial
title_full_unstemmed The Effect of Glycomacropeptide versus Amino Acids on Phenylalanine and Tyrosine Variability over 24 Hours in Children with PKU: A Randomized Controlled Trial
title_short The Effect of Glycomacropeptide versus Amino Acids on Phenylalanine and Tyrosine Variability over 24 Hours in Children with PKU: A Randomized Controlled Trial
title_sort effect of glycomacropeptide versus amino acids on phenylalanine and tyrosine variability over 24 hours in children with pku a randomized controlled trial
topic glycomacropeptide
phenylalanine
phenylketonuria
phenylalanine variability
amino acids
tyrosine
url https://www.mdpi.com/2072-6643/11/3/520
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