Growth trajectories in exclusively breastfed infants with clinically diagnosed food allergy: a prospective longitudinal cohort study

Abstract

Background Food allergy (FA) in infancy may be accompanied by feeding difficulties and dietary modifications during breastfeeding, which may influence early growth. However, longitudinal growth patterns in exclusively breastfed infants with clinically diagnosed FA remain incompletely characterized. Methods In this prospective longitudinal cohort study, 73 exclusively breastfed infants (30 with FA and 43 without FA) were enrolled at 4–6 months of age and followed through infancy. A total of 268 anthropometric observations were included in the longitudinal analysis. Weight-for-length Z-score (WLZ), weight-for-age Z-score (WAZ), length-for-age Z-score (LAZ), and head circumference-for-age Z-score (HCZ) were calculated according to the WHO Child Growth Standards. Growth trajectories were evaluated using linear mixed-effects models with infant-specific random intercepts. Age was modeled continuously and centered at 5 months. Sensitivity analyses examined nonlinear age effects and group-by-sex interactions. Results Maternal dietary avoidance was substantially more common among mothers of infants with FA than among those without FA (83.3% vs. 18.6%, p < 0.001). In the longitudinal WLZ model, the estimated difference between the NFA and FA groups at 5 months was 0.423 Z -score units (95% CI 0.036 to 0.811, p = 0.035), with lower estimated WLZ in the FA group. There was no evidence of a group-by-age interaction (estimate = −0.011, 95% CI − 0.086 to 0.063, p = 0.763), indicating no detectable difference in the linear rate of WLZ change between groups. Sensitivity analysis did not support a nonlinear WLZ trajectory, and no group-by-sex interaction was detected. Conclusion Infants with clinically diagnosed FA had lower estimated WLZ around 5 months of age than infants without FA, but the longitudinal analysis did not provide evidence that WLZ changed at a different linear rate between groups over time. Maternal dietary avoidance was substantially more common among mothers of infants with FA, underscoring the importance of appropriate nutritional counseling and growth monitoring in this population.

The authors' abstract, as published at the source. Frontiers in Nutrition, 2026 · DOI ↗