The Effect of Inulin Supplementation on Blood Lipid Levels, and Fecal Excretion of Bile Acid and Neutral Sterol in Korean Postmenopausal Women

ABSTRACT

Lipid-lowering effects of the inulin have been demonstrated in animal, yet attempts to reproduce similar effects in humans have generated conflicting results. In this study, the lipid-lowering potential of inulin and especially its effect on bile acid and neutral sterol excretion were investigated in Korean postmenopausal women. Nineteen postmenopausal women were randomly divided into two groups in a double-blind parallel design and consumed one of two supplements for 12 weeks; placebo of 8 g maltodextrins/sucrose mixture (placebo group) or 8 g inulin (inulin group). There were no significant changes in body weight during the supplementation period in either inulin or placebo group. Dietary consumption of animal fat in both group tended to decrease after 12 weeks of experiment. Intake of cholesterol was lower in placebo group, whereas the decrease of cholesterol intake in inulin group did not reach statistical significance after 12 weeks. The levels of serum total cholesterol (TC) and LDL-cholesterol (LDL-C) were significantly decreased in both placebo (p < 0.05) and inulin group (p < 0.01) after supplementation for 12 weeks compared with the baseline. The levels of serum triglyceride (TG) and HDL-cholesterol (HDL-C) were not significantly affected by inulin supplements, but atherogenic index (AI)and LDL-C/HDL-C ratio (LHR) as a predictor for coronary heart disease were improved (p < 0.01) significantly after inulin supplementation. Therefore, inulin supplement may decrease the risk of cardiovascular disease via improving blood cholesterol level. Fecal weight and pH were not changed after 12 weeks of supplementation. There were no statistically significant changes for the fecal short-chain fatty acids (SCFAs). In inulin group, fecal deoxycholic acid (DCA) was significantly lowered compared with the baseline (p < 0.05) whereas other bile acids were not changed. During the 12 weeks of intervention, no differences were found in fecal excretion of neutral sterol in the two groups. In summary, dietary inulin decreases serum TC, LDL-C, AI, LHR and lowers excretion of fecal DCA in the Korean postmenopausal women. These results support the use of inulin for reducing risk factors for hyperlipidemic postmenopausal women. However, the exact mechanism(s) responsible for the blood lipid lowering action of inulin including altered fecal bile acid remain to be elucidated.