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The Effect of Various Doses of Phenylalanine Supplementation on Blood Phenylalanine and Tyrosine Concentrations in Tyrosinemia Type 1 Patients
- Source :
- Nutrients, Volume 11, Issue 11, Nutrients, 11(11):2816. MDPI AG, Nutrients, Vol 11, Iss 11, p 2816 (2019)
- Publication Year :
- 2019
-
Abstract
- 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 &lt<br />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.
- Subjects :
- 0301 basic medicine
Adult
Male
medicine.medical_specialty
Adolescent
Phenylalanine supplementation
phenylalanine
Phenylalanine
lcsh:TX341-641
030105 genetics & heredity
Blood phenylalanine
Article
Tyrosinemia
03 medical and health sciences
Young Adult
0302 clinical medicine
Internal medicine
medicine
Humans
030212 general & internal medicine
Tyrosine
Enzyme Inhibitors
Child
Meal
Nutrition and Dietetics
Chemistry
Cyclohexanones
Tyrosinemias
NTBC
Tryptophan
MEN
medicine.disease
Heptanoates
TRYPTOPHAN
Endocrinology
Metabolic control analysis
Nitrobenzoates
Dietary Supplements
supplementation
Linear Models
Female
tyrosinemia type 1
lcsh:Nutrition. Foods and food supply
tyrosine
Food Science
Subjects
Details
- Language :
- English
- ISSN :
- 20726643
- Volume :
- 11
- Issue :
- 11
- Database :
- OpenAIRE
- Journal :
- Nutrients
- Accession number :
- edsair.doi.dedup.....62aeba311807b87ac312b1ac9b53b0b5