The bulk of dietary lipids is neutral fat or triglycerides composed of a glycerol backbone with each carbon linked to a fatty acid. Foodstuffs typically also contain phospholipids, sterols like cholesterol and many minor lipids, including fat-soluble vitamins. Finally, small intestinal contents contain lipids from sloughed epithelial cells and considerable cholesterol delivered in bile. In order for the triglyceride to be absorbed, two processes must occur: 1) large aggregates of dietary triglyceride, which are virtually insoluble in an aqueous environment, must be broken down physically and held in suspension - a process called emulsification, and 2) triglyceride molecules must be enzymatically digested to yield monoglyceride and fatty acids, both of which can efficiently diffuse or be transported into the enterocytes. The key players in these two transformations are bile acids and pancreatic lipase, which are mixed with semi-fluid mass of partially digested food that is expelled by the stomach into duodenum through pyloric valve and gets absorbed to the lymphatic fluid and then from the lymphatic fluid to the blood stream in the small intestine. Bile acids are also necessary to solubilize food lipids, including cholesterol. Bile acids play their first critical role in lipid assimilation by promoting emulsification. As derivatives of cholesterol, bile acids have both hydrophilic and hydrophobic domains.