Abstract
Summary: A supplement of the branched chain amino acids, valine, isoleucine, and leucine (VIL) was administered orally to patients with phenylketonuria, either together with unrestricted diet of natural protein or with a low phenylalanine diet. The VIL supplement brought about a significant reduction of the cerebrospinal fluid-serum ratio of phenylalanine from a mean value of 0.254 without VIL to 0.204 with VIL. The reduction varied from 15–40% (mean 21%). Concentrations of glycine, lysine, methionine, threonine, tryptophan, and tyrosine were within normal limits in serum and cerebrospinal fluid of infants with phenylketonuria. No amino acid imbalance was created by the supplement and no adverse effects from VIL were observed.
Speculation: The branched chain amino acids and phenylalanine share a common transport system. High levels of phenylalanine in brain of children with phenylketonuria may be reduced by administration of a supplement of valine, isoleucine and leucine (VIL). Supplementation of the low-phenylalanine diet with VIL during the first 2 years of life may add a measure of protection to the developing brain beyond that which can be achieved by diet alone. In older children, VIL supplementation may permit liberalization of the diet without unfavorable behavioral consequences.
Similar content being viewed by others
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Berry, H., Bofinger, M., Hunt, M. et al. Reduction of Cerebrospinal Fluid Phenylalanine after Oral Administration of Valine, Isoleucine, and Leucine. Pediatr Res 16, 751–755 (1982). https://doi.org/10.1203/00006450-198209000-00009
Issue Date:
DOI: https://doi.org/10.1203/00006450-198209000-00009
This article is cited by
-
Large neutral amino acids in the treatment of PKU: from theory to practice
Journal of Inherited Metabolic Disease (2010)
-
Large neutral amino acids supplementation in phenylketonuric patients
Journal of Inherited Metabolic Disease (2009)
-
Large neutral amino acids in the treatment of phenylketonuria (PKU)
Journal of Inherited Metabolic Disease (2006)
-
The role of the blood‐brain barrier in the aetiology of permanent brain dysfunction in hyperphenylalaninaemia
Journal of Inherited Metabolic Disease (1989)
-
Increased neurotransmitter biosynthesis in phenylketonuria induced by phenylalanine restriction or by supplementation of unrestricted diet with large amounts of tyrosine
European Journal of Pediatrics (1988)