Diana E. Roopchand, PhD

Assistant Professor, Department of Food Science
New Jersey Institute for Food, Nutrition, and Health
Rutgers, The State University of New Jersey, New Brunswick, NJ

 image of Dr. Diana Roopchand
Abstract: Poorly absorbed polyphenols are associated with metabolic resilience raising questions about their mechanisms of action. C57BL/6j mice fed high-fat diet (HFD) supplemented with 1% grape polyphenols (GP) for 12 weeks showed attenuated metabolic syndrome symptoms and changes in gut gene expression consistent with metabolic resilience. Mice also developed a bloom in Akkermansia muciniphila, a mucin dwelling gut microbe associated with metabolic health. To better understand the dynamics of these GP-induced changes we investigated the timing of the A. muciniphila bloom and the responsible class of GP. In two 14-day time course studies mice were fed HFD, low-fat diet (LFD), or formulations supplemented with 1% GP (HFD-GP, LFD-GP). Mice fed HFD-GP for two weeks showed significantly improved oral glucose tolerance (OGT) compared to control, while LFD and LFD-GP groups displayed similar OGT. In a separate study, mice gavaged with GP extract (GPE) or grape proanthocyanidins (PAC), in each case delivering 360 mg PAC/kg body weight, showed increased fecal and cecal A. muciniphila. Initial abundance of intestinal A. muciniphila determined the rate of GPE- or PAC-induced bloom. A. muciniphila growth in vitro was inhibited by exposure to GPE or PAC. Our data suggest that grape PAC are sufficient to induce a bloom of A.muciniphila, which can occur independently of specific changes in intestinal gene expression. In vitro inhibition of A. muciniphila by GPE or PAC suggests that, rather than directly promoting growth, PAC alter the gut microbiota providing A. muciniphila with a selective growth advantage that may benefit host metabolic health.