Effects of an infant formula containing a whey protein concentrate on feeding tolerance and markers of intestinal immune defense in Chinese infants

Abstract Background Human milk (HM) bioactive components can have immune modulatory functions, impact the gut microbiome, and may result in functional benefits when added to infant formula (IF). In this single-arm, prospective, intervention study, we tested the effectiveness of an IF with a whey protein concentrate co-enriched in α-lactalbumin, milk fat globule membrane (MFGM), and Sn-2 palmitate resulting in protein and lipid profiles observed in HM. The outcomes tested were feeding tolerance, Bifidobacteria abundance, and intestinal and immune health of Chinese infants. Methods Predominantly formula-fed (FF) and breastfed (BF) infants were enrolled between 3 and 28 days and assigned to the FF (N= 60) or BF (N=60) group, per their feeding practice, for 6 weeks. The primary endpoint was Infant Gastrointestinal Symptom Questionnaire (IGSQ) index score assessed using a validated IGSQ-13 questionnaire after 6 weeks of intervention; non-inferiority of FF vs BF was tested. Secondary endpoints included fecal Bifidobacteria abundance assessed using shotgun metagenomics sequencing; fecal short chain fatty acids (SCFAs) analyzed by ultra-performance liquid chromatography-tandem mass spectrometry; fecal markers of immune response, inflammation, intestinal barrier integrity (secretory immunoglobulin A sIgA), cytokines, calprotectin, α1 antitrypsin, lipocalin-2) assessed using enzyme-linked immunosorbent assay; stool consistency assessed using gastrointestinal (GI) diary; anthropometric assessments; quality of life; physician reported adverse events; and use of medications. Results Good GI tolerance was observed in both groups at V2 (mean±SD IGSQ score FF: 19.9±7.4; BF: 16.8±4.2); difference of means 1.35 [95% CI: -1.312, 4.012]). After 6 weeks, Bifidobacterium genus relative abundance was not significantly different between the groups. Total SCFAs were significantly higher (p