Fat absorption in the newborn.

Dietary fat is an important source of energy to the newborn. Pancreatic lipase and esterase activity are both low in newborns, particularly in premature ones; similarly, bile salt metabolism is markedly compromised. This could result in grossly defective intraluminal lipolysis and micellar solubilisation, leading to appreciable steatorrhea and energy loss. Lingual lipase and bile salt-stimulated lipase (BS-SL), however, play an important compensatory role. Lingual lipase is secreted from branching serous glands (von Ebner's glands) located on the dorsal aspect of the posterior region of the tongue, and its physicochemical properties are highly suited to passage through the stomach into the small intestine; a high fat diet and the act of suckling stimulates this enzyme's activity, and it may act in a synergistic fashion with pancreatic lipase. BS-SL (i.e. milk lipase) also has properties which are well designed for promoting fat absorption in the newborn. For example, it has no positional specificity for the ester bonds of the triglyceride molecule, and the optimal concentration of bile salts required for activation are low.