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Open AccessArticle

The Effect of Various Doses of Phenylalanine Supplementation on Blood Phenylalanine and Tyrosine Concentrations in Tyrosinemia Type 1 Patients

1
Department of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
2
Department of Metabolic Diseases, Birmingham Children’s Hospital, Birmingham B4 6NH, UK
3
Department of Dietetics, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
4
Department of Epidemiology, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
5
Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Nutrients 2019, 11(11), 2816; https://doi.org/10.3390/nu11112816
Received: 15 September 2019 / Revised: 12 November 2019 / Accepted: 15 November 2019 / Published: 18 November 2019
Tyrosinemia type 1 (TT1) treatment with 2-(2-nitro-4-trifluormethyl-benzyl)-1,3-cyclohexanedione (NTBC) and a phenylalanine-tyrosine restricted diet is associated with low phenylalanine concentrations. Phenylalanine supplementation is prescribed without comprehensive consideration about its effect on metabolic control. We investigated the effect of phenylalanine supplementation on bloodspot phenylalanine, tyrosine, NTBC and succinylacetone. Eleven TT1 patients received 0, 20 and 40 mg/kg/day phenylalanine supplementation with the phenylalanine-tyrosine free L-amino acid supplements. Bloodspots were collected before breakfast, midday and evening meal. Differences between study periods, sample times and days within a study period were studied using (generalized) linear mixed model analyses. Twenty and 40 mg/kg/day phenylalanine supplementation prevented daytime phenylalanine decreases (p = 0.05) and most low phenylalanine concentrations, while tyrosine concentrations increased (p < 0.001). Furthermore, NTBC and succinylacetone concentrations did not differ between study periods. To conclude, 20 mg/kg/day phenylalanine supplementation can prevent most low phenylalanine concentrations without increasing tyrosine to concentrations above the target range or influencing NTBC and succinylacetone concentrations, while 40 mg/kg/day increased tyrosine concentrations to values above the targeted range. Additionally, this study showed that the effect of phenylalanine supplementation, and a possible phenylalanine deficiency, should be assessed using pre-midday meal blood samples that could be combined with an overnight fasted sample when in doubt. View Full-Text
Keywords: tyrosinemia type 1; phenylalanine; supplementation; tyrosine tyrosinemia type 1; phenylalanine; supplementation; tyrosine
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MDPI and ACS Style

van Ginkel, W.G.; van Reemst, H.E.; Kienstra, N.S.; Daly, A.; Rodenburg, I.L.; MacDonald, A.; Burgerhof, J.G.M.; de Blaauw, P.; van de Krogt, J.; Santra, S.; Heiner-Fokkema, M.R.; van Spronsen, F.J. The Effect of Various Doses of Phenylalanine Supplementation on Blood Phenylalanine and Tyrosine Concentrations in Tyrosinemia Type 1 Patients. Nutrients 2019, 11, 2816. https://doi.org/10.3390/nu11112816

AMA Style

van Ginkel WG, van Reemst HE, Kienstra NS, Daly A, Rodenburg IL, MacDonald A, Burgerhof JGM, de Blaauw P, van de Krogt J, Santra S, Heiner-Fokkema MR, van Spronsen FJ. The Effect of Various Doses of Phenylalanine Supplementation on Blood Phenylalanine and Tyrosine Concentrations in Tyrosinemia Type 1 Patients. Nutrients. 2019; 11(11):2816. https://doi.org/10.3390/nu11112816

Chicago/Turabian Style

van Ginkel, Willem G.; van Reemst, Hannah E.; Kienstra, Nienke S.; Daly, Anne; Rodenburg, Iris L.; MacDonald, Anita; Burgerhof, Johannes G.M.; de Blaauw, Pim; van de Krogt, Jennifer; Santra, Saikat; Heiner-Fokkema, M. R.; van Spronsen, Francjan J. 2019. "The Effect of Various Doses of Phenylalanine Supplementation on Blood Phenylalanine and Tyrosine Concentrations in Tyrosinemia Type 1 Patients" Nutrients 11, no. 11: 2816. https://doi.org/10.3390/nu11112816

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