The effect of diets with various dietary fiber sources on
the plasma lipids, liver cholesterol, the histology of the
gastrointestinal tract, heart, liver and kidney and the
fecal neutral steroid excretion was investigated in
hamsters. 155, 9-11 wk old, male Golden-syrian hamsters
were fed a purified basal hypercholesterolemic diet (0.1%
cholesterol, 10% fat, 4% dietary fiber) for 5 wk to elevate
plasma lipid levels. Based on wk 4 plasma total cholesterol
(TC) levels hamsters with elevated levels were randomly
assigned, 16 animals/group, into six groups for another 4
wk: control, oat bran, guar gum, cellulose, xylan and
sacrifice. After 4 wk of the fiber diets (10% dietary
fiber), the plasma TC levels were significantly lowered in
the oat bran, guar gum and xylan groups (16%, 12% and 15%,
respectively) (p<.05). They were also significantly lower
than the control and cellulose groups. Plasma HDL-C
concentrations tended to be lower in all the treatment
groups, but was significantly decreased only in the guar gum
group (12%) (p<.05). The combined plasma VLDL-C + LDL-C was
significantly lowered by the oat bran, cellulose and xylan
diets (38%, 40% and 34%, respectively) (p<.05). The liver
cholesterol concentration increased significantly from
1 mg cholesterol/g liver to 4.1 mg cholesterol/g liver
(p<.05) after 4 wk of the control diet; this was further
increased significantly only in the cellulose group (5.6 mg
cholesterol/g liver), while the other treatment groups
showed no significant changes or differences compared to the
control diet group (wk 4). The total fecal neutral steroid
excretion was significantly (p<.05) higher in the oat bran
group compared to the other treatment groups. No major
differences were observed in the tissue histology of the
animals in the different treatment groups. In the present
study, it appeared that oat bran, guar gum and xylan were
effective hypocholesterolemic agents; however, their
mechanism of action is still not clear.
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