Choline concentration and composition in human milk across lactation stages: a systematic review and meta-analysis.

An adequate choline intake is essential for infant health. Choline profiles in human milk, critical for setting adequate intake levels and developing infant formulas, varied markedly across studies. This study aimed to systematically review and analyze choline concentrations and compositions in human milk and explore influencing factors. PubMed, Embase, Web of Science, Scopus, and CNKI were searched through August 16, 2025, for studies reporting total choline (TC) or water-soluble choline (WSC) concentrations in milk from healthy mothers within six months postpartum. Three-level meta-analytic models were used. Seventeen studies involving 1747 women were included. The primary analysis of seven studies reporting both TC and WSC showed a pooled TC concentration of 126.2 mg/L (95% CI: 103.7, 148.7), with WSC accounting for 83.3% (76.1%, 90.6%). The secondary analysis included ten additional studies reporting only WSC, estimating TC at 134.2 mg/L (122.6, 145.8), consistent with the primary analysis (p = 0.507). Across all studies, TC significantly increased from 71.5 mg/L in colostrum to 152.2 mg/L in transitional milk, then stabilized at 145.0 mg/L in mature milk. Although TC concentrations varied by assay methods and geographic regions, economic levels of countries demonstrated a significant influence. These findings could provide guidance for infant feeding.