More than 2 in 5 American adults (136 million people) have prediabetes, which places them at increased risk for developing type-2 diabetes (T2D) and cardiovascular disease (CVD). Dietary polyphenols in plant foods are associated with reduced risk and symptoms of chronic metabolic disease, but only about 10% of US adults consume the recommended daily servings of fruits and vegetables. Our preclinical murine studies have shown that Concord grape polyphenols (GPs), rich in the proanthocyanidin (PAC) class of compounds, can promote metabolic benefits at least in part by altering specific gut microbes and bile acids involved in glucose homeostasis. We performed a longitudinal, single arm intervention study to investigate how our murine data would translate to humans (NCT04018066). Metabolomic, metagenomic, and metaproteomic changes were measured in healthy participants (n= 27) before and after 5 days of soy protein isolate (SPI) supplementation alone followed by 10 days of supplementation with GPs complexed to SPI (GP-SPI). Serum, fecal, and urine samples were collected before and during the 17 day study and prepared for shotgun metagenomic sequencing, mass spectrometry-based metaproteomics, and targeted metabolomics (i.e., bile acids and polyphenols metabolites). Most multi-omic changes observed after 2 and/or 4 days of GP-SPI intake were temporary, returning to pre-supplementation profiles by day 10, suggesting microbial adaptation to PAC-rich GPs. Notably, 10 days of GP-SPI supplementation decreased fasting blood glucose in association with increased serum hyocholic acid (HCA), a bile acid known to promote glucose homeostasis through increasing glucagon-like peptide 1 (GLP-1). While causal relationships remain to be investigated, to our knowledge, this is the first study linking intake of GPs (mainly PACs) with increased serum HCA species, providing a novel mechanism by which GPs may contribute to glucose homeostasis.
Sunday October 11, 2026 9:00am - 10:00am PDT N214 Memorial Union518 Hitt St.
