Ea. Trautwein et al., DIETARY INULIN LOWERS PLASMA-CHOLESTEROL AND TRIACYLGLYCEROL AND ALTERS BILIARY BILE-ACID PROFILE IN HAMSTER, The Journal of nutrition, 128(11), 1998, pp. 1937-1943
The mechanisms by which inulin may elicit its lipid-lowering effect ar
e not well elucidated. To examine the lipid-lowering potential of inul
in and especially its effect on bile acid metabolism, male golden Syri
an hamsters were fed semipurified diets containing 20 g/100 g fat, 0.1
2 g/100 g cholesterol and 0 (control), 8, 12 or 16% inulin for 5 wk. P
lasma total cholesterol concentrations were significantly lowered by 1
8, 15 and 29% in hamsters fed 8, 12 and 16% inulin, respectively. Diet
ary inulin specifically decreased VLDL cholesterol, which was signific
antly lower in hamsters fed 16% inulin compared with controls (1.1 +/-
0.3 vs. 2.9 +/- 0.6 mmol/L). LDL and HDL cholesterol were not signifi
cantly affected by dietary inulin. Plasma triacylglycerol was signific
antly reduced by 40 and 63% in hamsters fed 12 and 16% inulin, respect
ively. Hepatic total cholesterol and particularly esterified cholester
ol accumulation were significantly lower in hamsters fed 8% inulin com
pared with controls. All three levels of dietary inulin caused distinc
t alterations in the bile acid profile of gallbladder bile. Taurocheno
deoxycholic acid was significantly lower, whereas glycocholic and glyc
odeoxycholic acid were greater in hamsters fed inulin. Daily fecal bil
e acid excretion (mu mol/d) tended to be greater (P = 0.056) in inulin
-fed hamsters compared with controls, whereas daily neutral sterol exc
retion was not affected. These data demonstrate that the lipid-lowerin
g action of inulin is possibly due to several mechanisms, including al
tered hepatic triacylglycerol synthesis and VLDL secretion and impaire
d reabsorption of circulating bile acids.