(P30-050-24) Assessing the Effect of California Grape Consumption on Gut Microbiome, Cardiovascular Health, Genomics and Metabolomics in Overweight Individuals – Study Protocol

Objectives: This study aims to demonstrate the capacity of California table grape consumption to counteract changes in gut microbiome, intestinal permeability, systemic inflammation, vascular function, genomic and metabolomic profiles associated with excess adiposity in overweight individuals, as well as to characterize sex-based response differences.

Methods: A randomized, cross-over, placebo-controlled design will be utilized. Participants will include 40 healthy individuals (20 men and menopausal women), aged 45-70 years, with BMI 25-30kg/m².

The dietary intervention consists of consumption of 40g/d freeze-dried grape powder (FDGP) vs 40g placebo. Two 4-week intervention periods will be separated by a 3-week washout period and a 1-week run-in period where participants will limit grape intake and other polyphenol-rich foods, followed by randomization to treatment order. Participants will dissolve FDGP in water and consume the drink, divided into two doses, morning and mid-day, while maintaining their usual diet without grapes and other polyphenol-rich foods. Compliance will be assessed using 3-day food intake records and assessment of blood polyphenols at each intervention end. The FDGP dose corresponds to 220g fresh grapes and provides ≈500mg of polyphenols/d. Anthropometrics, vascular function measurements, blood and fecal samples will be taken at beginning and end of each intervention.

Vascular outcomes include vascular stiffness and blood pressure, inflammatory and clinical lipid profiles, and intestinal outcomes include microbiome composition and gut permeability. Global genomics, metabolomic and lipidomic analyses will be conducted. Statistical analyses will be performed using linear mixed effects models, with transformed data if non-normality exists and multiple comparison corrections. Measured variables will be subjected to predictive modeling with partial least square regression.

Results: N/A

Conclusions: We anticipate to observe positive effect on vascular function, gut microbiome profile, intestinal permeability, associated with changes in cardiometabolic risk factors, which could be dependent on sex. Use of genomics, metabolomics and lipidomics will provide valuable insight into mechanisms underlying observed health effects.

Funding Sources: California Table Grape Commission