Dietary and Behavioral Determinants of Blood Phenylalanine Levels in Children With Phenylketonuria: A Cross-Sectional Study.

INTRODUCTION: Maintaining optimal blood phenylalanine (Phe) levels in children with phenylketonuria (PKU) depends on dietary, behavioral, and psychosocial factors. This study examined dietary and behavioral determinants of metabolic control in pediatric PKU. METHOD: This cross-sectional study included 50 children with PKU. Participants were categorized according to whether their Phe levels were within or above age-specific therapeutic target ranges. RESULTS: The mean Phe level was 536.3 ± 311.7 µmol/L, and 54% of participants had uncontrolled Phe values. Those with uncontrolled Phe levels more frequently exhibited poor dietary adherence, consumption of protein-rich foods, lack of satiety after meals, and social difficulties (p < .05), whereas no associations were observed for age and gender. Intake of protein-rich foods emerged as the strongest independent predictor of elevated Phe levels. CONCLUSION: Metabolic control in PKU is closely linked to feeding behaviors and psychosocial challenges. Health care providers should address behavioral and social barriers alongside dietary prescriptions to improve long-term Phe control.