Gene expression changes by high-polyphenols cocoa powder intake: a randomized crossover clinical study

Purpose To assess the effect of the intake of a single dose of high-polyphenols cocoa on gene expression in peripheral mononuclear cells (PBMCs), and analyze conjugated (-)-epicatechin metabolites in plasma, which may be related with an antioxidant response in healthy human. Methods A randomized, controlled, double-blind, cross-over, clinical trial in healthy young adults who consumed a single dose of high-polyphenols cocoa powder and maltodextrins as control, with a one-week washout period. Analysis of circulating metabolites, plasma antioxidant capacity and gene expression changes in PBMCs were performed under fasting conditions and 2-h after treatment using microarray in a subsample. Pathway analysis was conducted using Ingenuity Pathway Analysis (IPA). Results Twenty healthy participants (9F) were included in the study. A significant increase in circulating (-)-epicatechin metabolites was found after cocoa intake in all participants without related changes in antioxidant capacity of plasma. The metabolites profile slightly varied across subjects. Treatments triggered different transcriptional changes in PBMC. A group of 98 genes showed changes in expression after cocoa treatment, while only 18 were modified by control. Differentially expressed genes included inflammatory cytokines and other molecules involved in redox balance. Gene and network analysis after cocoa intake converged in functions annotated as decreased production of reactive oxygen species (p=9.58E-04), decreased leukocyte activation (p=4E-03) and calcium mobilization (p=2.51E-05). Conclusions No association was found between conjugated metabolites in plasma and antioxidant capacity. Changes in PBMCs gene expression suggest anti-inflammatory effects.