Abstract
OBJECTIVE: To test the long-term effect on growth status at 24 months of age in formula-fed infants who were randomized to consume a meat- or dairy-based complementary diet from 5 to 12 months of age. STUDY DESIGN: Observational assessments, including anthropometric, dietary, and blood biomarkers, were conducted at 24 months of age, 1 year after the intervention ended. RESULTS: The retention rate at 24 months of age was 84% for the meat group and 81% for the dairy group. Mean (±SD) protein intakes at 24 months of age were 4.1 ± 1.2 and 4.0 ± 1.1 g/kmeat (n = 27) and dairy (n = 26) groups, respectively, and comparable with the estimates of US population intake. At 24 months of age, weight-for-age z score did not differ significantly between groups and was similar to that at 12 months. Length-for-age z score remained significantly higher in the meat group compared with the dairy group, and the average length was 1.9 cm greater in the meat group. Weight-for-length z score also did not differ significantly between groups. Insulin-like growth factor 1 significantly increased from 12 to 24 months of age in both groups, but insulin-like growth factor-binding protein 3 and blood urea nitrogen did not change significantly from 12 to 24 months of age and were comparable between groups. CONCLUSIONS: The protein source-induced distinctive growth patterns observed during infancy persisted at 24 months of age, suggesting a potential long-term impact of early protein quality on growth trajectories in formula-fed infants. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02142647.