Abstract
When most people think of cholesterol, they think of the waxy fat- like substance that is found in many of the foods we eat. Often feared, the truth is that cholesterol is needed by the body for a number of different things. For example it is used in the manufacture and maintenance of strong cell walls, it is critical for hormone and vitamin D production, it even is used to coat the nerve cells in the body.
Introduction
Recently, studies in which the effects of dietary fiber on differences in plasma-cholesterol lowering between men and women were evaluated, men were more responsive than postmenopausal women in lowering plasma LDL cholesterol and apolipoprotein B (apo B) concentrations. In addition, reported data on guinea pigs demonstrate that females are more susceptible than males to a hypercholesterolemic diet; thus the cholesterol-lowering properties of dietary soluble fiber are not as effective as with male guinea pigs.
The study was performed to determine some of the mechanisms responsible for the plasma cholesterol lowering previously observed in female guinea pigs fed pectin, guar gum and psyllium and to evaluate whether those mechanisms are different from our reports in male guinea pigs. Guinea pigs were chosen in this and previous investigations , because, like humans, they transport cholesterol mainly in LDL, they have similar distribution of hepatic cholesterol pools with higher concentrations of free vs. esterified cholesterol and they have plasma cholesteryl ester transfer protein (CETP) activity, which makes the intravascular processing of lipoproteins analogous to that of humans. In addition, dietary fiber lowers plasma LDL cholesterol concentrations in guinea pigs as in humans; this has been documented in numerous reports from our laboratory. All of these characteristics make the guinea pig an appropriate animal model with which to evaluate the effects of dietary soluble fiber on the mechanisms of plasma LDL cholesterol lowering.
