Safety and efficacy of adding postbiotics in infant formula: a systematic review and meta-analysis

Postbiotics, as emerging products, were added to infant formula, but their safety and efficacy are unclear. To clarify this issue, we wrote this meta-analysis. We searched PubMed, Embase, Web of Science and ProQuest from its establishment to February 2023. The review was registered on PROSPERO database (CRD42022352405). The effects of infant formula with and without postbiotics were compared, and the incidence of serious adverse events (SAEs), digestive symptoms, concentration of stool secretory immunoglobulin A (SIgA), and growth and development indexes were analyzed. Nine randomized controlled trials with 2065 participants were included. The addition of postbiotics to infant formula was found to increase the concentration of stool SIgA (P < 0.05) with very low certainty of evidence, without significantly impacting the incidence of SAEs, infantile colic, flatulence, diarrhea, vomiting, abdominal pain and gastrointestinal disorders, the daily weight gain, the total gain in body length and the daily head circumference gain (all P > 0.05). Adding postbiotics to the formula is safe for infants, which would not increase the incidence of SAEs, infantile colic, flatulence, diarrhea, vomiting, abdominal pain, and gastrointestinal disorders, and could increase the concentration of stool SIgA. IMPACT: Our study provides evidence that the addition of postbiotics to infant formula is safe but not effective. This is the first systematic review and meta-analysis of postbiotics. This study provides strong evidence for the safety of postbiotics and lays a foundation for related clinical trials.