Effects of grape consumption on biomarkers of inflammation, endothelial function, and PBMC gene expression in obese subjects

This study investigated effects of grape consumption on biomarkers of cardiovascular health in obese participants in both postprandial and chronic settings. Twenty obese adults participated in this randomized, placebo controlled, double-blinded crossover trial. Participants were randomized to consume 60 g freeze-dried polyphenol-rich whole grape powder (GP) or placebo (PBO) followed by high fat high carbohydrate (HFHC) meal challenge. Following acute challenge, participants consumed their respective treatment daily for 4 weeks to determine effects of chronic consumption. Consumption of GP with HFHC meal significantly increased nuclear factor (erythroid-derived 2)-like 2 (NRF2) expression in peripheral blood mononuclear cells (PBMC) at 3 h (p < 0.05) and decreased plasma endothelin-1 (ET-1) concentration at 5 h (p < 0.05) after meal challenge compared with PBO. Following 4 weeks of daily GP consumption, soluble vascular cell adhesion molecule 1 (sVCAM-1) plasma concentration increased compared with PBO (p < 0.05), however baseline values differed between treatments. In conclusion, GP consumption resulted in decreased vasoconstrictor ET-1 concentration and increased gene expression related to oxidative stress defense following HFHC meal. Except for increase in sVCAM-1 concentration, 4 weeks of chronic GP consumption had little effect on cardiovascular biomarkers measured in this study. This trial was registered: clinicaltrials.gov NCT01674231.