Comparison of hypolipidemic effect of refined konjac meal with several common dietary fibers and their mechanisms of action.

The effects of RKM in comparison with pectin, algin and agar on lipid levels in serum and liver and on liver histopathology in rats were studied. In addition, the effects of all the tested materials on the composition and output of fecal bile acid were observed. All four kinds of dietary fiber were given at a level of 5% of diet to young male rats of Wistar strain fed on a lipid-rich diet containing 5% lard, 1% cholesterol and 0.25% cholate. All the dietary fibers tested have similar effects on serum lipid composition. In all groups, these substances prevented increases in total cholesterol in fasting serum, but the level of triglyceride was unchanged. The concentrations of total cholesterol and triglyceride in the liver were lower in the RKM group than in the control group and the other three groups. Hepatic histopathological examination also showed the most significant lipotropic effect in the RKM group. The daily output of fecal bile acids (CDCA + GDCA) was significantly increased in the four experimental groups than in the normal group and the control group. The increase of CDCA was more significant than GDCA, suggesting that the increase of fecal bile acids, especially CDCA, may be one of the mechanisms by which RKM and the other three dietary fibers exerts a hypocholesterolemic effect.