Sugar beet pulp and apple pomace dietary fibers improve lipid metabolism in rats fed cholesterol

The effect of diets supplemented with sugar beet pulp fiber (SBP, 10%) and apple pomace fiber (AP, 10%) on lipids and lipids peroxides was investigated in 60 male Wistar rats. The rats were divided into six groups of 10 and adapted to cholesterol-free or 0.3% cholesterol diets. The basal diet (BD) contained wheat meal, barley meal, wheat hulls, meat-bone meal, barley sprouts, skimmed milk, fodder yeast, mineral and vitamin mixtures. The Control group (Control) consumed BD only. To the BD were added 3 g/kg cholesterol (Chol), 100 g/kg dry sugar beet pulp fiber (SBP), both 100 g/kg sugar beet pulp fiber and 3 g/kg cholesterol (SBP+Chol), 100 g/kg apple pomace fiber (AP), both 100 g/kg apple pomace fiber and 3 g/kg cholesterol (AP+Chol). The experiment lasted 40 days. Plasma total cholesterol (TC), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), triglycerides (TG), total phospholipids (TPH), HDL phospholipids (HDL-PH), lipid peroxides (LP) and liver TC concentration were measured. Groups did not differ before the experiment. In the Chol+SBP and the Chol+AP vs. Chol group the sugar beet pulp and apple pomace dietary fiber supplemented diet significantly (P<0.05) hindered the rise of plasma lipids: (a) TC−2.97 vs. 3.69 mmol/l, −20% and 3.01 vs 3.69 mmol/l, −18.4%, respectively; (b) LDL-C −1.36 vs. 2.02 mmol/l, −32.6% and 1.39 vs. 2.02 mmol/l, −31.2%, respectively; (c) TG −0.73 vs. 0.88 mmol/l, and 0.75 vs. 0.88 mmol/l; −17 and −14.8%, respectively, and TC in liver (17.1 vs. 24.3 μmol/g, −29.6% and 17.9 v. 24.3 μmol/g, −26.3%, respectively. Sugar beet and apple pomace fiber-supplemented diets significantly hindered the decrease in HDL-PH (0.79 vs. 0.63 mmol/l, −25.3%, P<0.025 and 0.75 vs. 0.63 mmol/l, −19%, P<0.05, respectively) and decreased the level of TPH (1.34 vs. 1.74 mmol/l, −23%, P<0.005 and 1.37 vs. 1.74 mmol/l, −21.3%, P<0.01, respectively). Both sugar beet pulp fiber and apple pomace fiber, in rats fed the basal diet without cholesterol, did not significantly affect the variables measured. Neither sugar beet pulp fiber or apple pomace fiber-supplemented diets influenced the level of lipid peroxides. These results demonstrate that sugar beet pulp fiber and to a lesser degree apple pomace fiber possess hypolipidemic properties. This is more evident when sugar beet pulp fiber or apple pomace fiber are added to the diet of rats fed cholesterol. The hypolipidemic effects of both sugar beet pulp fiber and apple pomace fiber can be attributed to their water-soluble parts. The sugar beet pulp and apple pomace fibers have no antioxidant properties.