The Influence of Food on the In Vivo Bioavailability of DDT and Its Metabolites in Soil.

Incidental soil ingestion is considered to be an important route of exposure to hydrophobic organic contaminants (HOCs), such as dichlorodiphenyl-trichloroethane (DDT). Contaminant ingestion often occurs during food consumption; however, knowledge on the influence of food on DDT bioavailability remains limited. In this study, the relative bioavailability (RBA) of soil DDTr (i.e., DDT and metabolites) was determined using an in vivo mouse model in the presence of eight kinds of food including rice, egg, pork, pear, soybean, bread, spinach, and milk powder. The values of DDTr-RBA ranged from 19.8 ± 10.9 to 114 ± 25.1%. DDTr-RBA was positively correlated with fat (r = 0.71) and negatively correlated with fiber (r = 0.63) content in food. A mechanistic study showed that fat enhanced micellarization and promoted the formation of chylomicron, which facilitated the dissolution and transport of DDTr in the intestinal tract. Bioaccessibility of DDTr was determined using a physiologically based in vitro method. The addition of lipase significantly improved the ability of the method to predict DDTr-RBA, indicating that the "fasted state" in vitro method required optimization for food scenarios. To the best of our knowledge, this is the first study to explore the mechanistic influence of food on DDTr-RBA and provide important knowledge on dietary approaches for reducing exposure to HOCs.