GRAPE seed extract reduced high-sensitivity C-reactive protein (hs-CRP) and modestly improved disease activity in patients with mild-to-moderate ulcerative colitis (UC), although most outcomes did not differ significantly from placebo.
The randomised, triple-blind, placebo-controlled trial evaluated whether grape seed extract (GSE) supplementation affected immune-related gene expression, inflammatory biomarkers, disease activity, and quality of life in patients with mild-to-moderate UC. A total of 66 patients were randomly assigned to receive either GSE at 600 mg/day or placebo at 600 mg/day for 12 weeks.
Disease activity was assessed using the Simple Clinical Colitis Activity Index Questionnaire (SCCAIQ), while quality of life was measured using the Inflammatory Bowel Disease Questionnaire-9 (IBDQ-9). At the end of the study, 29 participants in each group had completed the trial.
Serum hs-CRP decreased significantly in both treatment groups, with a significantly greater reduction observed among patients receiving GSE compared with placebo at the end of the study: between-group p=0.002; change p=0.018.
SCCAIQ scores also decreased significantly within the GSE group: p=0.023. However, the difference between the GSE and placebo groups was not significant. These data suggest that the observed improvement in disease activity did not demonstrate superiority of GSE over placebo.
No significant between-group differences were identified for interleukin-17 (IL-17) or erythrocyte sedimentation rate. Expression of the immune-related genes T-bet and RORγt decreased in both groups, while FOXP3 and GATA3 expression increased. None of these gene expression changes differed significantly between groups.
Quality of life scores measured using the IBDQ-9 also showed no significant between-group difference. Overall, GSE was associated with a reduction in hs-CRP and a modest within-group improvement in disease activity, but the findings did not establish a broader benefit over placebo.
The researchers indicated that further clinical trials with larger sample sizes are needed to clarify the therapeutic potential of GSE in UC. Future studies should also include patients across a broader spectrum of disease activity to provide additional evidence regarding its potential clinical effects.
Reference
Heydarian A et al. Effects of grape seed extract on immune-related gene expression, inflammatory biomarkers, disease activity, and quality of life in patients with ulcerative colitis: a randomized, triple-blind, placebo-controlled trial. Sci Rep. 2026;DOI:10.1038/s41598-026-71714-9.
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