[Stimulation of the fecal excretion of polychlorinated biphenyls (KC-600) by diets containing rice bran fiber and cholestyramine].

Among the eight kinds of dietary fiber tested, rice bran fiber (RBF) mostly bound Kanechlor 600 (PCB) in vitro. The PCB bound to dietary fiber was in proportion to the lignin content in dietary fiber. We investigated whether RBF, lignin, cholestyramine and their combination stimulate the fecal excretion of PCB in rats. In the group fed a diet containing 10% (w/w) RBF, fecal excretion of PCB was stimulated. In the group fed a diet containing 10% (w/w) RBF and 5% (w/w) cholestyramine, more PCB was excreted in the feces. However, the group fed a diet containing 10% (w/w) RBF and 5% (w/w) lignin excreted the same amount of PCB as the group fed a diet containing 10% (w/w) RBF. The total PCB excreted into the feces for 21 days in the groups fed 10% (w/w) RBF, 10% (w/w) RBF and 5% (w/w) lignin, 5% (w/w) cholestyramine and 10% (w/w) RBF and 5% (w/w) cholestyramine diet was 3.4, 3.8, 2.3 and 5.7 times, respectively, that of the control. The stool transit time of rats fed 10% (w/w) RBF and 5% (w/w) cholestyramine diet was one hour faster than that of rats fed a 5% (w/w) cholestyramine diet. Therefore, we concluded that RBF has the greatest effect when administered in combination with cholestyramine on the fecal excretion of PCB.