Metabolomic Insights into the Nutritional Status of Adults and Adolescents with Phenylketonuria Consuming a Low-Phenylalanine Diet in Combination with Amino Acid and Glycomacropeptide Medical Foods.

Background: Nutrient status in phenylketonuria (PKU) requires surveillance due to the restrictive low-Phe diet in combination with amino acid medical foods (AA-MF) or glycomacropeptide medical foods (GMP-MF). Micronutrient profiles of medical foods are diverse, and optimal micronutrient supplementation in PKU has not been established.

Methods: In a crossover design, 30 participants with PKU were randomized to consume AA-MF and Glytactin™ GMP-MF in combination with a low-Phe diet for 3 weeks each.

Reassessment of phenylalanine tolerance in adults with phenylketonuria is needed as body mass changes.

Lifelong treatment of phenylketonuria (PKU) includes a phenylalanine (phe) restricted diet that provides sufficient phe for growth and maintenance plus phe-free amino acid formula to meet requirements for protein, energy and micronutrients. Phe tolerance (mg phe/kg body weight/day) is the amount of phe those with PKU can consume and maintain acceptable blood phe levels; it requires individual assessment because of varying phenylalanine hydroxylase activity. The objective was to reassess phe tolerance in eight adults with PKU considering phe requirements, blood phe levels, genotype and phe tolerance at 5 years of age.

Improved nutritional management of phenylketonuria by using a diet containing glycomacropeptide compared with amino acids.

Background: Phenylketonuria (PKU) requires a lifelong low-phenylalanine diet that provides the majority of protein from a phenylalanine-free amino acid (AA) formula. Glycomacropeptide (GMP), an intact protein formed during cheese production, contains minimal phenylalanine.

Objective: The objective was to investigate the effects of substituting GMP food products for the AA formula on acceptability, safety, plasma AA concentrations, and measures of protein utilization in subjects with PKU.

Acceptable low-phenylalanine foods and beverages can be made with glycomacropeptide from cheese whey for individuals with PKU.

Glycomacropeptide (GMP) is a whey protein that contains no aromatic amino acids including phenylalanine (phe). The objective of this study was to make a variety of palatable, low-phe foods and beverages with GMP and to assess their acceptability by conducting consumer sensory studies in individuals with PKU. Results demonstrate acceptability of products made with GMP.