The Short-Chain Fatty Acid Uptake Fluxes by Mice on a Guar Gum Supplemented Diet Associate with Amelioration of Major Biomarkers of the Metabolic Syndrome

Abstract

Studies with dietary supplementation of various types of fibers have shown beneficial effects on symptoms of the metabolic syndrome. Short-chain fatty acids (SCFAs), the main products of intestinal bacterial fermentation of dietary fiber, have been suggested to play a key role. Whether the concentration of SCFAs or their metabolism drives these beneficial effects is not yet clear. In this study we investigated the SCFA concentrations and in vivo host uptake fluxes in the absence or presence of the dietary fiber guar gum. C57Bl/6J mice were fed a high-fat diet supplemented with 0%, 5%, 7.5% or 10% of the fiber guar gum. To determine the effect on SCFA metabolism, 13C-labeled acetate, propionate or butyrate were infused into the cecum of mice for 6 h and the isotopic enrichment of cecal SCFAs was measured. The in vivo production, uptake and bacterial interconversion of acetate, propionate and butyrate were calculated by combining the data from the three infusion experiments in a single steady-state isotope model. Guar gum treatment decreased markers of the metabolic syndrome (body weight, adipose weight, triglycerides, glucose and insulin levels and HOMA-IR) in a dose-dependent manner. In addition, hepatic mRNA expression of genes involved in gluconeogenesis and fatty acid synthesis decreased dose-dependently by guar gum treatment. Cecal SCFA concentrations were increased compared to the control group, but no differences were observed between the different guar gum doses. Thus, no significant correlation was found between cecal SCFA concentrations and metabolic markers. In contrast, in vivo SCFA uptake fluxes by the host correlated linearly with metabolic markers. We argue that in vivo SCFA fluxes, and not concentrations, govern the protection from the metabolic syndrome by dietary fibers.

Consumption of antimicrobial manuka honey does not significantly perturb the microbiota in the hind gut of mice

“…There were some effects on formate and succinate production, but we found no impact on the numbers of some relevant microbial groups, or other less directly-relevant groups. Further investigation with stable isotope labelling, organic acid uptake flux analyses (Den Besten et al, 2014) or detailed phylogenetic analyses using next generation sequencing may shed light here, although in light of the current findings we do not consider them to be justified (Hanage, 2014). …”

Comparisons of Effects on Intestinal Short-Chain Fatty Acid Concentration after Exposure of Two Glycosidase Inhibitors in Mice

“…The concentrations of SCFA, including acetate, propionate and butyrate in intestinal tract increased in varying degrees after extra addition of slowly digested carbohydrates in daily diets, such as resistant starch, 39) guar gum, 40) pectin, 41) inulin 42) and so on. In this study, acarbose and voglibose significantly increased butyrate concentration (Fig.…”

Vinegar as a functional ingredient to improve postprandial glycemic control—human intervention findings and molecular mechanisms

“…This further suggests that activation of FFAR2 by acetic acid locally in the intestinal L‐cells, via nutrient sensing, leading to increased GLP‐1 and other anorexegenic hormone secretions may be more important than the systemic effects of acetate. Furthermore, in a recent study using a mouse model, it was shown that SCFA flux might be important in determining the beneficial effects of SCFAs in improving metabolic homeostasis . This may therefore provide a further explanation of the increased effectiveness of vinegar in healthy subjects, who have an increased acetate turnover rate and therefore greater intestinal acetate flux, as will be discussed in more detail in Section of this review.…”