Beta-glucans supplementation associates with reduction in P-cresyl sulfate levels and improved endothelial vascular reactivity in healthy individuals

Abstract

Background: Oat and barley beta-glucans are prebiotic fibers known for their cholesterol-lowering activity, but their action on the human gut microbiota metabolism is still under research. Although the induction of short-chain fatty acids (SCFA) following their ingestion has previously been reported, no study has investigated their effects on proteolytic uremic toxins p-cresyl sulfate (pCS) and indoxyl sulfate (IS) levels, while others have failed to demonstrate an effect on the endothelial function measured through flow-mediated dilation (FMD). Objective: The aim of our study was to evaluate whether a nutritional intervention with a functional pasta enriched with beta-glucans could promote a saccharolytic shift on the gut microbial metabolism and improve FMD. Methods: We carried out a pilot study on 26 healthy volunteers who underwent a 2-month dietary treatment including a daily administration of Granoro "Cuore Mio" pasta enriched with barley beta-glucans (3g/100g). Blood and urine routine parameters, serum pCS/IS and FMD were evaluated before and after the dietary treatment. Results: The nutritional treatment significantly reduced LDL and total cholesterol, as expected. Moreover, following beta-glucans supplementation we observed a reduction of serum pCS levels and an increase of FMD, while IS serum levels remained unchanged. Conclusions: We demonstrated that a beta-glucans dietary intervention in healthy volunteers correlates with a saccharolytic shift on the gut microbiota metabolism, as suggested by the decrease of pCS and the increase of SCFA, and associates with an improved endothelial reactivity. Our pilot study suggests, in addition to cholesterol, novel pCS-lowering properties of beta-glucans, worthy to be confirmed in large-scale trials and particularly in contexts where the reduction of the microbial-derived uremic toxin pCS is of critical importance, such as in chronic kidney disease.