On the extent of hydrolysis of triglyceride ester bonds in the lumen of human small intestine during digestion.

Abstract

Summary.Glycerides containing a fraction of a percentage of 2,2‐dimethyl[1‐14C] long‐chain fatty acids, the ester bonds of which are resistent to the action of pancreatic lipase, have been fed to human subjects.From the concentration of the labelled acid in the neutral fat of the intestinal contents it is possible to calculate the real extent of hydrolysis of the glyceride esters fed if it is assumed that the different glycerides are absorbed at the same rate.The results show that as a mean around sixty per cent of fed glyceride ester bonds are split in the lumen of the small intestine before absorption. About forty per cent of the fed triglycerides are completely hydrolyzed to glycerol and fatty acids, the remaining sixty per cent are partly hydrolyzed to an extent of around forty per cent, giving rise to a mixture of tri‐, di‐ and monoglycerides and free fatty acids.It is, therefore, clear that fatty acids fed to human subjects in the form of triglycerides are absorbed from the small intestine to a greater extent as free fatty acids than as glycerides.We are indebted to Prof. S. Bergström for placing the 13C‐labelled glycerides at our disposal.The technical assistance of Mrs. M. B. Nilsvik and Miss K. Sjöström is gratefully acknowledged. The investigation has been supported by grants from Statens Medicinska Forsk‐ningsråd, from Knut och Alice Wallenbergs Stiftelse, from the Medical Faculty of the University of Lund and from Statens naturvetenskapliga forskningsråd.