Use of satiety peptides in assessing the satiating capacity of foods.

Foods differ in their satiating capacity. Satiety peptides may help to provide evidence for biological mechanisms behind these differences. The aim of this paper was to discuss the physiological relevance of three individual appetite peptides, i.e. CCK, GLP-1 and PYY, in assessing the satiating capacity of foods. A literature research was conducted on CCK, GLP-1, PYY and satiety; effective exogenous infusion studies and endogenous production studies, i.e. changes induced by foods, were identified. The relative changes in blood concentrations in these studies were compared in order to assess an indication of the physiological relevance of the peptides. Relative changes in the two types of studies investigating CCK overlapped, i.e. increases in serum were 3 to 14-fold in effective exogenous studies (n=7) and 2 to 8-fold in endogenous production studies (n=9). The relative changes in GLP-1 and PYY did not overlap; GLP-1: 4 to 16 fold in effective exogenous studies (n=4) and no effect to 4 fold in endogenous production studies (n=38). PYY: 3 to 11-fold in effective exogenous studies (n=14) and no effect to 2-fold in endogenous production studies (n=10). GLP-1 and PYY show effects on satiety at supra-physiological dosages, they are not likely to contribute individually to a difference in satiating capacity of foods and can therefore not be interpreted in isolation. The effects of CCK are likely to be in the physiological range and therefore may have an individual contribution to a difference in satiating capacity between foods.