In vitro digestion and bioaccumulation of food-born processing contaminant 3-MCPD diesters in rats

3-Monochloropropane-1,2-diol (3-MCPD) is a process-born contaminant formed during edible oil refining. While toxicity of free 3-MCPD is well established and strictly regulated, the digestive fate, absorption and tissue distribution of its fatty acid diesters remains insufficiently characterised. This study examined the hydrolysis and bioaccumulation of 3-MCPD diesters through in vitro gastro-intestinal digestion, their absorption/transport in lymph and plasma as well as their bioaccumulation in rat tissues. We showed that both, gastric and pancreatic lipases can hydrolyze 3-MCPD diesters, reaching 4.34 ± 0.24% and 15.38 ± 0.98%, respectively. This resulted in a cumulative absorption in lymph of 17.4 ± 1.5% over 24 h, with approximately 65% occurring within the first 6 h postprandially (11.3 ± 2.1%). Moreover, after four weeks of dietary exposure, 3-MCPD diesters predominantly accumulated in the liver, gonads, kidneys, brain and heart, with higher tissue concentrations observed in females, particularly in liver and ovaries. Although the digestive hydrolysis of 3-MCPD esters remains limited, their absorption nevertheless leads to a selective storage in tissues, contributing to sex-related differences in toxicity.