Abstract Objectives Breast‐fed (BF) have lower risk of infections during infancy compared to those formula‐fed (FF). A higher content of alpha‐lactalbumin (α‐lac) in breast milk, which may promote a more favorable gut microbiota, could be one reason. In this study, we evaluated whether increased concentration of α‐lac in low‐protein infant formula affects the immune response and the incidence of infections during infancy. Methods In a double‐blinded randomized controlled trial, healthy‐term infants ( n = 245) received low‐protein infant formulas with α‐lac‐enriched whey (α‐lac‐EW; 1.75 g protein/100 kcal, 27% α‐lac) or casein glycomacropeptide‐reduced whey (CGMP‐RW; 1.76 g protein/100 kcal, 14% α‐lac), or standard formula (SF; 2.2 g protein/100 kcal, 10% α‐lac) from 2 to 6 months. BF constituted a reference group. Cytokines and high‐sensitivity C‐reactive protein (hsCRP) were measured during intervention and infection‐related morbidity, and treatment was evaluated until 12 months. Results Serum interleukin‐6 (IL‐6) was lower in BF than in all FF groups during intervention ( p < 0.001). No other differences in cytokines (tumor necrosis factor alpha TNF‐α, transforming growth factor beta 1 TGF‐β1, TGF‐β2, IL‐1, IL‐10, IL‐12, interferon gamma INF‐γ) or hsCRP were found among the study groups. Infection‐related morbidity did not differ among study groups, except slight differences in the use of antibiotics during (α‐lac‐EW vs. CGMP‐RW p = 0.008) and after intervention (α‐lac‐EW vs. BF p = 0.016). Conclusions Increased α‐lac concentration in low‐protein infant formula to levels similar to breast milk did not affect the cytokine profile and had minor effect on infection‐related morbidity. The higher IL‐6 concentrations in FF than in BF needs further investigation.
Nilsson et al. (Fri,) studied this question.