[Binding of PCB by several types of dietary fiber in vivo and in vitro]

We investigated the binding of PCB by dietary fiber in vivo and in vitro. Forty male rats consisting of four rats a group were housed and rats of each group were given a treatment diet containing rice-bran fiber, spinach fiber, burdock fiber, cabbage fiber, soybean fiber Japanese-radish fiber, carrot fiber, corn fiber and cellulose for five days. The remaining four rats were fed a non-fiber diet as controls. The animals were administered with 0.5 ml of the race-bran oil used by Yusho patients and kept on the same diets for five days. Fecal excretion of PCB in the group fed rice-bran fiber and spinach fiber was significantly (p < 0.01) stimulated 6.6 and 4.1 times, respectively, as compared with controls. Dietary fiber was suspended in distilled water, and methanolic solution of PCB was added to these suspensions. The mixtures were then incubated. After centrifugation, the unbound PCB in supernatant was analyzed by gas chromatograph. Rice-bran fiber and spinach fiber bount more PCB than any of the other dietary fiber. A significant correlation existed between the amounts of binding PCB in vitro and fecal PCB output in rats by eight types of dietary fiber (r = 0.986, p < 0.01).