Polyphenolic fractions isolated from red raspberry whole fruit, pulp, and seed differentially alter the gut microbiota of mice with diet-induced obesity

Polyphenol extracts from red raspberry (RR) whole fruit or pulp, but not seed, attenuate high-fat (HF) diet-induced obesity in mice. Because host metabolism is linked to the microbiota, we investigated the effects of polyphenols from RR fruit, pulp, and seed on the microbiome. RR polyphenols significantly decreased the abundance of specific taxa that were increased during HF feeding relative to a low-fat diet, including Ruminococcus and an unclassified genus from Clostridiales. Compared to a HF diet, pulp and seed polyphenols increased Roseburia abundance and decreased levels of an unclassified genus from Mogibacteriaceae. RR seed polyphenols uniquely increased Bifidobacterium compared to a HF diet. The most notable taxon driving differential abundance among all diets was an unclassified genus from Coriobacteriaceae. Importantly, host metabolic markers improved by pulp polyphenols were strongly correlated with select microbiome features, indicating that specific gut bacteria may be involved in RR polyphenol catabolism and/or mediating health benefits.