alpha-Galacto-oligosaccharides Dose-Dependently Reduce Appetite and Decrease Inflammation in Overweight Adults

International audienceBackground: Dietary fibers have been associated with a reduction in appetite and energy intake. Although a few studies suggest that nonviscous fibers can exert such effects, likely through colonic fermentation, limited data are available. Objective: The objective of this study was to determine whether alpha-galacto-oligosaccharides (alpha-GOSs), fermentable soluble fibers extracted from legumes, could reduce appetite, food intake, and inflammation in overweight subjects. Methods: In 2 single-center, double-blind, randomized, placebo-controlled trials, 88 overweight adults [50% men and 50% women; 18-60 y old; body mass index (in kg/m(2)): 25-28] were supplemented for 14 d with tea that contained alpha-GOSs with different alpha-GOS dosages (6, 12, or 18 g alpha-GOSs/d), formulas (12 g alpha-GOSs/d with > 80% of molecules with a degree of polymerization of 2, 3, or 4), or a control substance (glucose syrup). Appetite scores (5 appetite dimensions were assessed on visual analog scales during a preload test meal), food intake (test meal and 24-h food recall), and inflammatory markers [plasma lipopolysaccharide (LPS) and C-reactive protein (CRP)] were evaluated at day 0 (baseline) and day 15. Results: Changes in appetite scores from day 0 to day 15 were significantly higher after alpha-GOS intake, with areas under the curve for the satiety score of + 121 +/- 108, +218 +/- 218, and +306 +/- 205 score . min for 6, 12, and 18 g alpha-GOSs/d, respectively, and -5 +/- 64 score . min for the control group. We observed dose-dependent effects that did not vary by alpha-GOS composition. The administration of 6, 12, or 18 g alpha-GOSs/d significantly and dose-dependently increased the change in energy intake from day 0 to day 15 during a test meal (-13 +/- 19, -26 +/- 22, and -32 +/- 22 kcal, respectively; +6 +/- 21 kcal for the control group). Reductions in energy intake during lunch and dinner were also higher in the alpha-GOS groups in the dose-effect study. At day 15, LPS was dose-dependently reduced without an association with alpha-GOS composition (0.16 +/- 0.02, 0.12 +/- 0.08, and 0.08 +/- 0.05 EU/mL for 6, 12, and 18 g alpha-GOSs/d, respectively, and 0.06 +/- 0.04 EU/mL for the control group) and CRP was significantly lower in the alpha-GOS groups than in the control group in the formulation-effect study. Conclusions: Consumption of alpha-GOSs for 14 d dose-dependently reduced appetite, food intake, and inflammation in overweight adults with no impact of alpha-GOS composition. Consequently, alpha-GOSs appear to promote long-term weight loss and mitigate metabolic disorders