Phenylalanine-Free Infant Formula in Patients with Phenylketonuria: A Retrospective Study

• Published in: Nutrients 2024-07, Vol.16 (14), p.2204
• Main Authors: Yilmaz Nas, Ozlem, Ashmore, Catherine, Evans, Sharon, Pinto, Alex, Daly, Anne, Yabancı Ayhan, Nurcan, MacDonald, Anita
• Format: Article
• Language: English
• Subjects: Age; Amino acids; Babies; Baby foods; Body mass index; Caregivers; Child; Child, Preschool; Constipation - diet therapy; Data collection; Diet; Dietary Proteins - administration & dosage; Energy Intake; Enzymes; Families & family life; Female; growth; Hospitals; Humans; infancy; Infant; Infant Formula; infant protein substitute; Longitudinal Studies; Male; Marital status; Medical screening; metabolic control; Metabolism; Newborn babies; Nutrition research; Parent educational background; Phenylalanine - administration & dosage; Phenylalanine - blood; Phenylketonuria; Phenylketonurias - diet therapy; Proteins; Retrospective Studies; Software; Statistical analysis; Trace elements
• ISSN: 2072-6643; 2072-6643
• DOI: 10.3390/nu16142204

The long-term efficacy and use of phenylalanine-free infant amino acid formula (PFIF) is understudied. This retrospective, longitudinal study evaluated PFIF (PKU Start: Vitaflo International) in children with phenylketonuria, collecting data on metabolic control, growth, dietary intake, and symptoms and the child's experience with PFIF. Twenty-five children (12 males, 48%) with a median age of 3.6 years (2.0-6.2 years) were included. During 24 months follow-up, children maintained normal growth and satisfactory metabolic control. The protein intake from protein substitutes increased from 2.7 at 6 months to 2.8 g/kg/day at 24 months, while natural protein decreased from 0.6 to 0.4 g/kg/day. By 24 months, most children (n = 16, 64%) had stopped PFIF, while nine (36%) continued with a median intake of 450 mL/day (Q1:300 mL, Q3: 560 mL). Children who continued PFIF after 24 months of age had higher energy and fat intakes with higher weight/BMI z-scores compared with those who stopped earlier ( < 0.05). Constipation was reported in 44% of infants but improved with age. Initial difficulty with PFIF acceptance was reported in 20% of infants but also improved with time. Prolonged use of PFIF in pre-school children may contribute to poor feeding patterns and overweight; thus, replacing the majority of the protein equivalent provided by PFIF with a weaning protein substitute by 12 months and discontinuing PFIF before 2 years is recommended.