Background:Polar lipid (PL) emulsifiers such as milk PLs (MPLs) may affect digestion and subsequent lipid metabolism,but focused studies on postprandial lipemia are lacking.Objective:We evaluated the impact of MPLs on postprandial lipemia in mice and on lipid digestion in vitro.Methods:Female Swiss mice were gavaged with 150mL of oil-in-water emulsion stabilized with 5.7 mg of either MPLs or soybean PLs (SPLs) and killed after 1, 2, or 4 h. Plasma lipids were quantified and in the small intestine, gene expression was analyzed by reverse transcriptase–quantitative polymerase chain reaction. Emulsions were lipolyzed in vitro using a static human digestion model; triglyceride (TG) disappearance was followed by thin-layer chromatography. Results:In mice, after 1 h, plasma TGs tended to be higher in the MPL group than in the SPL group (141 mg/mL vs. 90mg/mL; P = 0.07) and nonesterified fatty acids (NEFAs) were significantly higher (64 mg/mL vs. 44 mg/mL;P