Dietary protein content and its impact on amino acid profile and appetite in patients with methylmalonic acidemia
- 1Division of Pediatric Metabolism, Department of Pediatrics, Ankara University Faculty of Medicine, Ankara, Turkiye.
- 2Ankara University Rare Diseases Research and Application Center, Ankara, Turkiye.
- 3Department of Physiopathology, Ankara University, Ankara, Turkiye.
Abstract
Background: Medical formulas used in the dietary management of methylmalonic acidemia (MMA) are typically enriched in leucine and may contribute to branched-chain amino acid imbalance and appetite suppression. However, the relationship between dietary protein composition, circulating leucine levels, and appetite-regulating hormonal pathways in MMA remains unclear.
Objectives: To investigate the impact of dietary protein content and medical formula proportion on plasma amino acid profiles, appetite scores, and appetite-related hormonal regulation in pediatric patients with MMA.
Design: Prospective, single-center, three-phase dietary intervention study.
Methods: Ten pediatric patients with genetically confirmed MMA underwent a sequential three-step dietary intervention in which both total protein intake and the proportion of leucine-rich medical formula varied across phases. Each phase lasted at least two months. At the end of each phase, plasma amino acid levels (leucine, valine, and isoleucine), appetite-related hormones and peptides (GLP-1, ghrelin, neuropeptide Y [NPY], agouti-related peptide [AgRP], insulin, and leptin), and caregiver-reported appetite scores were assessed using fasting blood samples whenever clinically feasible, with a minimum fasting interval of 4 hours accepted in younger children.
Results: The dietary phases were associated with significant differences in plasma leucine and GLP-1 levels, with higher levels observed during the first phase than during the final phase (p=0.032 and p=0.002, respectively). Ghrelin, NPY, and AgRP levels also differed significantly across dietary phases (p=0.034, p=0.011, and p=0.012, respectively), alongside significantly improved appetite scores (p=0.001). No significant differences were observed in insulin or leptin concentrations across dietary phases.
Conclusion: In children with MMA, changes in dietary protein composition and medical formula exposure were associated with improved appetite and changes in appetite-related hormonal profiles. Because both total protein intake and medical formula intake changed across the study phases, the independent effects of protein quantity and protein source could not be determined. These findings suggest a potential association between dietary protein composition and appetite regulation in MMA but should be interpreted cautiously given the exploratory design and limited sample size.
Registration: Not applicable.
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BibTeX
@article{kose2026dietary,
title = {{Dietary protein content and its impact on amino acid profile and appetite in patients with methylmalonic acidemia}},
author = {Engin Köse and Neslihan Doğulu and Furkan Yolcu and Naci Polat and Fatma Tuba Eminoğlu},
journal = {Therapeutic Advances in Endocrinology and Metabolism},
year = {2026},
month = sep,
doi = {10.1177/20420188261489499},
url = {https://doi.org/10.1177/20420188261489499},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Dietary protein content and its impact on amino acid profile and appetite in patients with methylmalonic acidemia
AU - Engin Köse
AU - Neslihan Doğulu
AU - Furkan Yolcu
AU - Naci Polat
AU - Fatma Tuba Eminoğlu
PY - 2026
DA - 2026/09/17
JO - Therapeutic Advances in Endocrinology and Metabolism
DO - 10.1177/20420188261489499
UR - https://doi.org/10.1177/20420188261489499
AB - Background: Medical formulas used in the dietary management of methylmalonic acidemia (MMA) are typically enriched in leucine and may contribute to branched-chain amino acid imbalance and appetite suppression. However, the relationship between dietary protein composition, circulating leucine levels, and appetite-regulating hormonal pathways in MMA remains unclear. Objectives: To investigate the impact of dietary protein content and medical formula proportion on plasma amino acid profiles, appetite scores, and appetite-related hormonal regulation in pediatric patients with MMA. Design: Prospective, single-center, three-phase dietary intervention study. Methods: Ten pediatric patients with genetically confirmed MMA underwent a sequential three-step dietary intervention in which both total protein intake and the proportion of leucine-rich medical formula varied across phases. Each phase lasted at least two months. At the end of each phase, plasma amino acid levels (leucine, valine, and isoleucine), appetite-related hormones and peptides (GLP-1, ghrelin, neuropeptide Y [NPY], agouti-related peptide [AgRP], insulin, and leptin), and caregiver-reported appetite scores were assessed using fasting blood samples whenever clinically feasible, with a minimum fasting interval of 4 hours accepted in younger children. Results: The dietary phases were associated with significant differences in plasma leucine and GLP-1 levels, with higher levels observed during the first phase than during the final phase (p=0.032 and p=0.002, respectively). Ghrelin, NPY, and AgRP levels also differed significantly across dietary phases (p=0.034, p=0.011, and p=0.012, respectively), alongside significantly improved appetite scores (p=0.001). No significant differences were observed in insulin or leptin concentrations across dietary phases. Conclusion: In children with MMA, changes in dietary protein composition and medical formula exposure were associated with improved appetite and changes in appetite-related hormonal profiles. Because both total protein intake and medical formula intake changed across the study phases, the independent effects of protein quantity and protein source could not be determined. These findings suggest a potential association between dietary protein composition and appetite regulation in MMA but should be interpreted cautiously given the exploratory design and limited sample size. Registration: Not applicable.
SN - 2042-0188
SN - 2042-0196
ER -