Plasma levels of cholecystokinin and peptide YY in humans: Response to dietary fats of different degrees of unsaturation (olive and sunflower oil)

The influence of the type of dietary fat (degree of unsaturation) upon plasma levels of cholecystokinin (CCK) and peptide YY (PYY) was investigated in cholecystectomized human. The levels of these peptides were examined before and after the administration of isocaloric liquid meals containing olive (Group O) or sunflower oil (Group S) to the subjects who for thirty days prior to surgery had been comsuming (30 days) diets in which olive (Group O) and sunflower oil (Group S) were the main source of dietary fat. Plasma levels of CCK were greater in Group O throughout the entire postprandial period. Fasting plasma PYY concentration was significantly higher in Group O than in Group S. No significant changes in plasma PYY were found after food ingestion in either group, although the concentration of this hormone in Group O was consistently higher than in Group S. It is concluded that these type of dietary fats affect plasma CCK and PYY concentrations and that the postprandial release of PW is mediated, at least in part, by CCK.