Soluble Fiber with High Water-Binding Capacity, Swelling Capacity, and Fermentability Reduces Food Intake by Promoting Satiety Rather Than Satiation in Rats

Abstract

To understand whether soluble fiber (SF) with high water-binding capacity (WBC), swelling capacity (SC) and fermentability reduces food intake and whether it does so by promoting satiety or satiation or both, we investigated the effects of different SFs with these properties on the food intake in rats. Thirty-two male Sprague-Dawley rats were randomized to four equal groups and fed the control diet or diet containing 2% konjac flour (KF), pregelatinized waxy maize starch (PWMS) plus guar gum (PG), and PWMS starch plus xanthan gum (PX) for three weeks, with the measured values of SF, WBC, and SC in the four diets following the order of PG > KF > PX > control. Food intake, body weight, meal pattern, behavioral satiety sequence, and short-chain fatty acids (SCFAs) in cecal content were evaluated. KF and PG groups reduced the food intake, mainly due to the decreased feeding behavior and increased satiety, as indicated by decreased meal numbers and increased inter-meal intervals. Additionally, KF and PG groups increased concentrations of acetate acid, propionate acid, and SCFAs in the cecal contents. Our results indicate that SF with high WBC, SC, and fermentability reduces food intake-probably by promoting a feeling of satiety in rats to decrease their feeding behavior.

Keywords: food intake; guar gum; meal pattern; satiety; water binding capacity.

Figure 1

Food intake and body weight. (A) Average daily food intake; (B) cumulative food intake; (C) final body weight; and (D) body weight gain in rats given diets containing different dietary fibers for three weeks. Diets were control (C) or supplemented with 2% fiber of konjac flour (KF), pregelatinized waxy maize starch plus guar gum (PG) or pregelatinized waxy maize starch plus xanthan gum (PX); Values are mean ± SEM of n = 8 per group. Bars with different letters indicate a significant difference (p < 0.05).

Figure 1

Food intake and body weight. (A) Average daily food intake; (B) cumulative food intake; (C) final body weight; and (D) body weight gain in rats given diets containing different dietary fibers for three weeks. Diets were control (C) or supplemented with 2% fiber of konjac flour (KF), pregelatinized waxy maize starch plus guar gum (PG) or pregelatinized waxy maize starch plus xanthan gum (PX); Values are mean ± SEM of n = 8 per group. Bars with different letters indicate a significant difference (p < 0.05).

Figure 2

Food intake (A) in rats was calculated at 1 h and is presented as mean ± SEM for n = 8 per group. Bars with different letters indicate a significant difference (p < 0.05). Periods 1–12 correspond to the twelve 5-min time bins comprising the 60 min test session; (B–E) Frequency data within each behavioral category are expressed as a proportion of the total number of observations per time bin; (F–I) correspond to crossover graphs illustrating the point of transition from eating to resting. The perpendicular line indicates satiety point. Diets were control (C) or supplemented with 2% fiber of konjac flour (KF), pregelatinized waxy maize starch plus guar gum (PG), or pregelatinized waxy maize starch plus xanthan gum (PX).

Figure 3

Plasma concentrations (A) and mRNA abundance in distal ileum (B) of GLP-1 and PYY in rats given diets containing different dietary fibers for three weeks; Diets were control (C) or supplemented with 2% fiber of konjac flour (KF), pregelatinized waxy maize starch plus guar gum (PG), or pregelatinized waxy maize starch plus xanthan gum (PX); Values are mean ± SEM, n = 6–8 per group. GLP-1, glucagon-like peptide-1; PYY, peptide tyrosine-tyrosine.

Figure 4

Concentration of SCFAs in cecal contents of rats given diets containing different dietary fibers for three weeks. Diets were control (C) or supplemented with 2% fiber of konjac flour (KF), pregelatinized waxy maize starch plus guar gum (PG) or pregelatinized waxy maize starch plus xanthan gum (PX); Values are mean ± SEM of n = 6–8 per group. Bars with different letters indicate a significant difference (p < 0.05). SCFAs, short-chain fatty acids; AC, acetate acid; PC, propionate acid; BC, butyrate acid.