Key Points
Research has also shown that consumption of some types of dietary fibre, particularly soluble dietary fibre (SDF) can attenuate glycemic responses. Thus diets enriched with SDF are recommended to individuals with Type 2 diabetes (T2D) to improve glycemic control and to the general population to reduce the risk of T2D. The main goal of the present work was to examine the mechanisms involved in postprandial glycemia and insulinemia attenuation with SDF consumption proposed in the literature. The results of the current study showed that supplementation of treatments with three types of SDF (ethanol-treated yellow mustard mucilage (YMM-ETH), ethanol-treated soluble flaxseed gum (SFG-ETH), and water-extracted fenugreek gum (FG-WE) (significantly reduced glucose and plasma Cmax values compared to controls. The concentration of each SDF type was chosen to result in equivalent viscous characteristics in the small intestinal lumen, which was established by in vitro experiments. Therefore, attenuation of postprandial glycemic and insulinemic responses observed in the present study were independent of the source of SDF but were rather affected by the ability of SDF to alter physical properties of the solution. Recommended dietary amounts of each SDF type should be specified based on the viscous properties of a particular SDF in aqueous solution. It was concluded that the delay of sugar transport from the small intestinal luminal bulk is not a primary mechanism involved in the attenuation of postprandial glycemic and insulinemic responses after consumption of SDF. The progress of starch hydrolysis does not have a substantial effect on glycemic and insulinemic responses either. Based on the postprandial changes of plasma paracetamol concentration, delay of gastric emptying caused by SDF could be the main mechanism involved in observed attenuation of glycemic and insulinemic responses.
ABSTRACT
This work examines the mechanisms involved in the attenuation of postprandial glycemic and insulinemic responses associated with soluble dietary fibre (SDF) consumption. The effect of SDF, including yellow mustard mucilage, soluble flaxseed gum and fenugreek gum on in vitro amylolysis and maltose transport was studied. Furthermore, a human clinical trial was conducted to investigate the effect of SDF consumption on postprandial glycemic and insulinemic responses and gastric emptying, as estimated based on the absorption of paracetamol. Participants (n = 15) at risk for type II diabetes consumed maltose syrup- and starch-based pudding treatments supplemented with each SDF, each at a concentration to match three times the apparent viscosity (18.54 mPa s at 60 s-1) equivalent to the European Food Safety Authority (2011) glycemia control health claim for cereal β-glucan, measured under simulated small intestinal conditions. The presence of each SDF delayed in vitro amylolysis to a similar extent, but had no effect on maltose transport. Generally, all SDF-containing treatments attenuated blood glucose and plasma insulin peak concentrations and plasma paracetamol 1 h incremental area under the curve values to a similar extent, relative to the controls, despite differences in the amounts at which each SDF was used (from 5.9 to 15.5 g). The postprandial attenuations were related to the ability of each SDF to modify digesta viscosity, perhaps through the delay of gastric emptying, as a delay of amylolysis and sugar transport under simulated upper intestinal conditions did not seem to have a substantial effect.
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