Red Raspberry Polyphenols and Fructo-oligosaccharide on Gut Microbiome

This study aimed to investigate if supplementation with (poly)phenol-dense red raspberries (RRB) alone or with a fructo-oligosaccharide (FOS) prebiotic would improve biomarkers of cardio-metabolic risk in individuals with prediabetes and insulin resistance (PreDM-IR) and whether the effects are related to modulation of the gut microbiota.Adults with PreDM-IR or that were metabolically healthy participated in a randomized crossover trial with two 4-week supplementation periods consuming RRB (125 g fresh equivalents) daily or RRB+8g FOS daily separated by a 4-week washout. The primary outcome variable was the composition of gut microbiota by shotgun sequencing assessed before and at the end of each supplementation period. Secondary outcomes were markers of glucose and lipid metabolism, anti-inflammatory status, and anthropometry.