Effects of soluble corn bran arabinoxylans on cecal digestion, lipid metabolism, and mineral balance (Ca, Mg) in rats.

The effects of soluble corn bran arabinoxylans on cecal digestion, lipid metabolism, and mineral utilization [calcium (Ca) and magnesium (Mg)] were investigated in rats adapted to semipurified diets. The diets provided either 710 g/kg wheat starch alone (control) or 610 g/kg wheat starch plus 100 g/kg corn soluble fiber (arabinoxylans) and either 0 or 2 g/kg cholesterol (control + cholesterol and arabinoxylans + cholesterol, respectively). Compared with rats fed the control diets, rats fed the arabinoxylan diets had significant cecal hypertrophy (+50% after 3 days of the fiber adaptation) and an accumulation of short-chain fatty acids, especially propionic acid (up to 45% in molar percentage).

Cholesterol-lowering effects of guar gum: changes in bile acid pools and intestinal reabsorption.

Soluble fibers such as guar gum (GG) may exert cholesterol-lowering effects. It is generally accepted that bile acid (BA) reabsorption in portal blood is reduced, thus limiting the capacity of BA to down-regulate liver cholesterol 7alpha-hydroxylase, the rate-limiting enzyme of BA synthesis. In the present work, rats were adapted to fiber-free (FF) or 5% GG diets (supplemented or not with 0.

Effectiveness of resistant starch, compared to guar gum, in depressing plasma cholesterol and enhancing fecal steroid excretion.

Amylase-resistant starch (RS) represents a substrate that can be administered in substantial amounts in the diet, in contrast to gel-forming polysaccharides, such as guar gum (GG). The aim of this work was thus to compare the effects of GG and RS on cholesterol metabolism in rats adapted to 0.4% cholesterol diets, using dietary GG or RS levels (8 or 20%, respectively) that led to a similar development of fermentations, as assessed by the degree of enlargement of the cecum.

Resistant starch is more effective than cholestyramine as a lipid-lowering agent in the rat.

Amylase-resistant starch (RS) represents a substrate for the bacterial flora of the colon, and the question arises as whether RS shares with soluble fibers common mechanisms for their lipid-lowering effects. It is uncertain whether a cholesterol-lowering effect depends basically on an enhanced rate of steroid excretion or whether colonic fermentations also play a role in this effect. In the present study, the effect of RS (25% raw potato starch), of a steroid sequestrant (0.