Effect of Short-Term Grape Powder Supplementation in Patients with Crohn's Disease: A Pilot Study

Background: The overall objective of this pilot diet intervention study was to determine the effect of grape powder (GP) supplementation on gut microbiota composition and inflammatory markers in individuals with Crohn's disease (CD). Methods: Adult CD participants were recruited from the Digestive Health Institute at University Hospitals Medical Center, Cleveland. All participants were supplemented with 45 g/day of freeze-dried grape powder (equivalent to ~1.5 cups of fresh grapes) daily for 21 days. The primary outcome was the change in fecal microbiome profiles. Secondary outcomes included the absolute difference (day 21-day 0) in Harvey Bradshaw Index (HBI) score, fecal myeloperoxidase (MPO), and high-sensitivity C-reactive protein (hsCRP). Results: A total of 21 CD participants were included in the final analysis. After 21 days of GP supplementation, more than half of the participants (13, 61.9%) experienced a reduction in fecal MPO, while 80% (17) experienced either a reduction or no change in HBI score. Microbiome analysis revealed modest but directional shifts, including enrichment of Akkermansiaceae, Bacteroidaceae, Tannerellaceae, Rikenellaceae, and Monoglobaceae. While overall community structure did not significantly change at the cohort level, individualized microbiome responses as well as functional pathway shifts were observed following the intervention. Conclusions: Daily supplementation with freeze-dried grape powder for 21 days was safe and well-tolerated in adults with CD and was associated with modest shifts in gut microbiome composition. This study was registered on clinicaltrials.gov (NCT05972694; 5 February 2024).