In vitro Digestive Lipolysis and Intestinal Lipid Absorption in Mice

Impact of Dietary Polar Lipids from Different Sources on

in vitro Digestive Lipolysis and Intestinal Lipid Absorption in Mice

Manon Lecomte¹, Claire Bourlieu², Gaëlle Pineau¹, Mathilde Claude², Alain Géloën¹, Fabienne Laugerette¹, and Marie-Caroline Michalski<sup>1

1</sup>INRA USC1362, INSERM U1060, INSA-Lyon, CarMeN laboratory,

Lyon, France

² INRA-Agrocampus, UMR 1253 Science and Technology of Milk and Eggs,

Rennes, France

Metabolic diseases of nutritional origin, such as obesity and type 2 diabetes, are characterized by disordered lipid metabolism including postprandial hyperlipemia. Recent works suggest that the composition of dietary fat can modulate the kinetics of postprandial lipemia. In this context, polar lipids (PL) are of utmost importance in food formulation because of their multifunctionality and excellent emulsifying properties. Recently, interest has developed on potential beneficial metabolic effect of dietary PL, among which is improved lipid metabolism. In the present study, we hypothesized that (i) PL from different sources (vegetal vs animal) could have a different impact on postprandial lipemia and (ii) this could be linked to different digestive lipolysis due to emulsion interface. For this purpose, mice were administrated an oral gavage of triacylglycerols (TAG) emulsified with soybean PL or milk PL. The two emulsions presented similar initial lipid phase surface area (i.e. ~24 m²/g of lipid). After gavage, blood samples were collected. We observed higher plasma TAG and Free Fatty Acids (FFA) concentrations at 1 h in mice fed with the milk PL emulsion. Noteworthy, at 4 h plasma TAG and FFA concentrations were significantly lower for these mice suggesting that the kinetics of TAG-rich lipoproteins in plasma depends on the type of emulsifier. Additionally, the two emulsions were digested in vitro using a static model of human digestion (gastric and intestinal phases of 60 minutes using simulated digestive fluids and porcine enzymes mainly). In the gastric phase, the hydrolysis kinetics of TAG were comparable however in the intestinal phase, the kinetics of lipolysis of the milk PL emulsion were faster than the soybean PL emulsion.

All together, these data suggest that the quality of PL have an impact on digestive lipolysis and postprandial lipemia.