Trial reportThe American journal of clinical nutrition2016
Glycomacropeptide for nutritional management of phenylketonuria: a randomized, controlled, crossover trial.
Trial report in The American journal of clinical nutrition, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT01428258 (Phase 2 Study of Glycomacropeptide vs. Amino Acid Diet for the Management of PKU), which is not on this map. Cited by 47 papers, 2 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Phase 2 Study of Glycomacropeptide vs. Amino Acid Diet for the Management of PKU
Who cites it
47 citing papers in PubMed, 2 syntheses or guidelines pooled it, 85 citations in OpenAlex.
- Morphofunctional Assessment beyond Malnutrition: Fat Mass Assessment in Adult Patients with Phenylketonuria-Systematic Review.Nutrients · 2024Pooled it
- The Use of Glycomacropeptide in Patients with Phenylketonuria: A Systematic Review and Meta-Analysis.Nutrients · 2018Pooled it
- Protein Substitute Absorption: A Randomised Controlled Trial Comparing CGMP vs. Amino Acids vs. Micellar Casein in Healthy Volunteers.Nutrients · 2025Trial
- Trial
- Metabolomic Markers of Essential Fatty Acids, Carnitine, and Cholesterol Metabolism in Adults and Adolescents with Phenylketonuria.The Journal of nutrition · 2018Trial
- Metabolomic changes demonstrate reduced bioavailability of tyrosine and altered metabolism of tryptophan via the kynurenine pathway with ingestion of medical foods in phenylketonuria.Molecular genetics and metabolism · 2017Trial
- Observational
- Nutritional and Therapeutic Strategies in Paediatric Phenylketonuria: A Narrative Literature Review.Nutrients · 2026Review
- Global Use of Casein Glycomacropeptide Protein Substitutes for Phenylketonuria (PKU): Health Professional Perspectives.Nutrients · 2026Article
- Review
- The relationship between adult phenylketonuria and the cardiovascular system - insights into mechanisms and risks.Orphanet journal of rare diseases · 2025Review
- Current Insights into Nutritional Management of Phenylketonuria: An Update for Children and Adolescents.Children (Basel, Switzerland) · 2025Review
- Diagnosis, treatment, management and monitoring of patients with tyrosinaemia type 1: Consensus group recommendations from the German-speaking countries.Journal of inherited metabolic disease · 2025Review
- Protein requirements in adults with phenylketonuria and bioavailability of glycomacropeptide compared to an l-amino acid-based product.Journal of inherited metabolic disease · 2025Article
- Glycomacropeptide-Based Protein Substitutes for Children with Phenylketonuria in Italy: A Nutritional Comparison.Nutrients · 2024Review
- Article
- Evaluation of a New Glycomacropeptide-Based Protein Substitute in Powdered and Liquid Format in Patients with PKU.Nutrients · 2023Article
- Characterization of Choline Nutriture among Adults and Children with Phenylketonuria.Nutrients · 2022Article
- Body Composition in Adolescent PKU Patients: Beyond Fat Mass.Children (Basel, Switzerland) · 2022Article
- Quality of life aspects of a low protein diet using GMP in patients with phenylketonuria.The Journal of international medical research · 2022Observational
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
7 authors at 3 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundTo prevent cognitive impairment, phenylketonuria requires lifelong management of blood phenylalanine (Phe) concentration with a low-Phe diet. The diet restricts intake of Phe from natural proteins in combination with traditional amino acid medical foods (AA-MFs) or glycomacropeptide medical foods (GMP-MFs) that contain primarily intact protein and a small amount of Phe.
objectiveWe investigated the efficacy and safety of a low-Phe diet combined with GMP-MFs or AA-MFs providing the same quantity of protein equivalents in free-living subjects with phenylketonuria.
designThis 2-stage, randomized crossover trial included 30 early-treated phenylketonuria subjects (aged 15-49 y), 20 with classical and 10 with variant phenylketonuria. Subjects consumed, in random order for 3 wk each, their usual low-Phe diet combined with AA-MFs or GMP-MFs. The treatments were separated by a 3-wk washout with AA-MFs. Fasting plasma amino acid profiles, blood Phe concentrations, food records, and neuropsychological tests were obtained.
resultsThe frequency of medical food intake was higher with GMP-MFs than with AA-MFs. Subjects rated GMP-MFs as more acceptable than AA-MFs and noted improved gastrointestinal symptoms and less hunger with GMP-MFs. ANCOVA indicated no significant mean ± SE increase in plasma Phe (62 ± 40 μmol/L, P = 0.136), despite a significant increase in Phe intake from GMP-MFs (88 ± 6 mg Phe/d, P = 0.026). AA-MFs decreased plasma Phe (-85 ± 40 μmol/L, P = 0.044) with stable Phe intake. Blood concentrations of Phe across time were not significantly different (AA-MFs = 444 ± 34 μmol/L, GMP-MFs = 497 ± 34 μmol/L), suggesting similar Phe control. Results of the Behavior Rating Inventory of Executive Function were not significantly different.
conclusionsGMP-MFs provide a safe and acceptable option for the nutritional management of phenylketonuria. The greater acceptability and fewer side effects noted with GMP-MFs than with AA-MFs may enhance dietary adherence for individuals with phenylketonuria. This trial was registered at www.clinicaltrials.gov as NCT01428258.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.