COMPARISON OF THE HYPOLIPIDEMIC EFFECTS OF REFINED KONJAC MEAL WITH SEVERAL COMMON DIETARY FIBERS AND THEIR MECHANISMS OF ACTION / 营养学报

ABSTRACT

In order to evaluate appropriately the role of lipid metabolism by the refined konjac meal (RKM), a new source of dietary fiber, the effects of RKM on the level of serum and liver lipids, hepatic histopathology and on the composition and output of fecal bile acids in comparison with pectin, algin and agar were studied.The RKM contained about 75-80% of glucomannan. All four kinds of dietary fiber "were given at a level of 5% in the diet to the young male Wistar rats fed on a lipid-rich diet containing 5% lard, 1% cholesterol and 0.25% chplate. The control group was fed on a lipid-rich diet alone withput fiber. The normal group was fed on a basal diet without extra lipid added. Feeding period was 9 weeks.The results obtained were as follows;1)All the dietary fibers tested have the similar effects on serum lipid composition. At the end of 2-week of the experiment, the serum total cholesterol levels of the four experimental groups were only 62% to 75% of that of the control group, and at the end of 7-week they were lowered to the same level of the normal group. The level of the triglyceride in serum did not change in all groups during the experiment.2)Relative liver weights were lower in four experimental groups than in control group. Hepatic hisiopathological examinations showed lipotropic effect in RKM, pectin and algin groups. Both of the above effects appeared most significantly in RKM group. The concentrations of total cholesterol and triglyceride in liver in RKM group were lower than those in control group as well as other three experimental groups.3)No harmful effects on the intake of food and growing of rats were found when feeding these four kinds of dietary fiber at the level of 5%.4)The daily output of fecal bile acids (CDCA + GDCA) was significantly increased in four experimental groups.The increase of fecal output of bile acids, especially CDCA, may be one of the mechanisms of hypocholesterola-emic effect of dietary fibers.It could be concluded that RKM has the same significant hypocholestero-lemic effect as the pectin, algin and agar, but its lipotropic effect is more potent.