Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/20/2007
Publication Date: 11/3/2007
Citation: Hong, Y., Turowski, M., Lin, J.T., Yokoyama, W.H. 2007. Simultaneous Characterization of Bile Acid, Sterols, and Determination of Acyglycerides in Feces from Soluble Cellulose-Fed Hamsters using HPLC with Evaporative Light Scattering Detection and APCI-MS. Journal of Agricultural and Food Chemistry. 55:9759-9757. Interpretive Summary: Soluble fibers have been known to lower LDL cholesterol in blood, therefore reducing the risk of heart disease. However, the mechanism by which soluble fibers show these beneficial effects has not been clarified yet. In order to see the effect of soluble modified cellulose on lipid metabolism, we used a hamster animal model and showed that soluble modified cellulose resulted in the increase in the excretion of bile acids, cholesterol metabolites as well as total fecal fat, indicating that soluble cellulose appears to alter the cholesterol metabolism and prevent TG absorption. This study can shed a light on the mechanism of some soluble fibers beneficial to health.
Technical Abstract: The rapid rise in obesity-related diseases has increased interest in oral and dietary agents that disrupt fat metabolism resulting in the excretion of dietary lipids in the feces. In this study, a rapid and convenient liquid chromatography method to comprehensively analyze fecal lipids in a single injection was developed. An evaporative light scattering detector (ELSD) for routine analysis, or atmosphere pressure chemical ionization tandem mass spectrometry ((+)APCI-MS/MS) for structural confirmation and peak purity were used. The method was applied to characterize lipid components of feces from hamsters fed high-fat diets with either 5% microcrystalline cellulose or 5% hydroxypropyl methylcellulose (HPMC) fibers in order to test the effect of HPMC on lipid metabolism. HPMC is a non-fermentable, soluble cellulose fiber. The fecal lipid components identified using this method includes two secondary bile acids, deoxycholic acid, lithocholic acid and neutral sterols including cholesterol, coprostanol, sitostanol and stigmastanol. The profile of fecal lipid components was compared between the two groups. It was found that the bile acid excretion was increased two-fold in HPMC fed hamsters. More interestingly, diacylglycerides and triacylglycerides were detected in feces from hamsters on HPMC included high fat diets and further identified by APCI-MS/MS. We believe that this is the first report of excretion of acylglycerides following neutral soluble fiber feeding.