Grape Impact on Human Gut Microbiome

The human gut microbiome consists of trillions of microorganisms that are essential tohost metabolism, immune system regulation, and the maintenance of disease resistance.Recent findings indicate that dietary changes can rapidly and significantly alter thecomposition of these microbial communities, leading to substantial effects on the host'soverall physiology. Foods rich in polyphenols are highly effective at modulating thisenvironment because they possess selective antimicrobial properties and exert beneficialprebiotic effects on the resident microbiota.Polyphenol‐rich foods beneficially modulate the human gut microbiome with downstreammetabolic and immune effects. California table grapes contain a complex mixture ofphenolics, resveratrol, flavans, flavonols, and anthocyanins, making them idealcandidates for investigating gastrointestinal and immune health. However, previousgrape‐microbiome studies have been limited by small sample sizes (n=21‐29), shortdurations (2 weeks), low‐resolution microbiome technologies (16S profiling), and failureto measure corresponding inflammatory or immune biomarkers.This project will first conduct a microbiome screening phase in up to 300 healthy adultsto identify individuals who meet pre‐specified microbiome and other study eligibilitycriteria. Eligible individuals may then be invited to participate in a rigorous,multi‐omic pilot study using standardized freeze‐dried grape powder to determine howdaily grape consumption modulates the gut microbiome‐immune axis in up to 40 healthyadults. The study team will employ state‐of‐the‐art metagenomic sequencing to achievehigh‐resolution microbiome profiling; metabolomic analysis; and immune biomarkerprofiling to assess gastrointestinal inflammation.Specific AimsOverarching Goal: To build on our unique expertise in high‐resolution microbiome analysesto conduct a rigorous, multi‐omic pilot study determining how daily consumption ofCalifornia table grape powder modulates the human gut microbiome‐immune axis in healthyadults.Hypothesis: Compared to a placebo, daily consumption of California table grape powderwill beneficially modulate the gut microbiome by: (1) altering microbial composition; (2)shifting the fecal metabolome to increase grape‐derived and microbial‐derivedanti‐inflammatory compounds; and (3) reducing baseline biomarkers of gastrointestinalinflammation.