Retrospective Evaluation of Diet Compliance on Plasma Amino Acid and Vitamin Levels in Patients with Phenylketonuria

Year 2025, Volume: 9 Issue: 1, 158 - 165, 31.01.2025

Buse Aytop Kol , Özlenen Şimşek Papur , Bahar Kulu , Nur Arslan

https://doi.org/10.30621/jbachs.1539286

Abstract

Retrospective Evaluation of Diet Compliance on Plasma Amino Acid and Vitamin Levels in Patients with Phenylketonuria

Abstract

Purpose: In this study, it was aimed to compare the plasma amino acid and blood vitamin/mineral levels in patients with classical phenylketonuria and healthy controls.
Material and Methods: 54 patients with classical phenylketonuria and 22 healthy controls (76 children, 47 boys, 61.8%) were included in the study. The patient group was divided into two subgroups as high adherence to phenylalanine-restricted diet (HAD, 16 patients) and low adherence to this diet (LAD, 38 patients) according to the mean plasma phenylalanine level of the patients of the previous year. Anthropometric measurements (body weight and height and standard deviation score values), plasma phenylalanine and other amino acid levels, hemoglobin, vitamin B12, folic acid, vitamin D, zinc, ferritin levels of all groups were recorded.
Results: The mean age of the entire study group was 10.1 ± 3.6 (minimum: 3.5 - maximum: 17) years. There was no significant difference between the phenylketonuria group and the control group in terms of age, gender distribution and anthropometric data. There was a significant difference between the three groups in terms of plasma phenylalanine levels (plasma phenylalanine levels 299.0 ± 77.2; 813.7 ± 356.6 and 47.5 ± 15.9 µmol/L in HAD, LAD and control groups respectively, p= 0.001). Tryptophan was significantly lower in the HAD group than in the LAD and control groups (p= 0.001 and p= 0.006, respectively). Lysine was found to be significantly higher and histidine was lower in the HAD group than the control group (p= 0.016 and p= 0.008, respectively). Hemoglobin, vitamin B12, folic acid and 25-OH vitamin D levels were found to be significantly higher in the PKU patient group compared to healthy children and no difference between zinc and ferritin levels.
Conclusion: As a result, in patients with phenylketonuria who comply with the diet and whose anthropometric data are in the normal range, no significant deterioration in vitamin/mineral and amino acid values is observed. Compliance of the patients with a diet restricted from phenylalanine will both reduce the neurological effects and ensure that the patient is nutritionally balanced.

Keywords

Classical phenylketonuria, phenylalanine-restricted diet, hemoglobin, plasma amino acids, vitamins

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