PP395 - EVALUATING EVIDENCE ON POLYPHENOL INTAKE AND DIGESTIVE SYSTEM CANCER RISK: AN UMBRELLA REVIEW OF META-ANALYSES AND SYSTEMATIC REVIEWS

PP395

EVALUATING EVIDENCE ON POLYPHENOL INTAKE AND DIGESTIVE SYSTEM CANCER RISK: AN UMBRELLA REVIEW OF META-ANALYSES AND SYSTEMATIC REVIEWS

M. Gholamalizadeh^1,*, S. Doaei², H. Abbasi³

¹Nutrition and Cancer Unit, ²Cancer Epidemiology Research Program, Catalan Institute of Oncology, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain., Barcelona, Spain, ³Student Research Committee, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran., Tehran, Iran, Islamic Republic Of

Rationale:  This umbrella review synthesizes evidence from meta-analyses on the association between dietary polyphenol consumption and the risk of DSCs, addressing limitations in the literature and identifying optimal polyphenol types and doses.

Methods:  In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive literature search was performed across PubMed, Scopus, and Web of Science up to April 2025. The search strategy incorporated predefined keywords related to polyphenols and digestive system cancers (DSCs). Eligible studies were meta-analyses that investigated the association between polyphenol intake and the risk of DSCs. Methodological quality was evaluated using the AMSTAR 2 tool, and the certainty of evidence was assessed based on the GRADE framework. Statistical analyses were conducted using RStudio, applying random-effects models in consideration of between-study heterogeneity.

Results:  A total of six meta-analyses, comprising 27 effect sizes, were included in the final analysis. The pooled results indicated a statistically significant 11% reduction in the risk of DSCs associated with polyphenol intake (RR: 0.89; 95% CI: 0.85–0.93; I²: 63%). Subgroup analyses demonstrated significant inverse associations for specific classes of polyphenols, including flavonols (22% reduction), quercetin (22%), anthocyanidins (16%), flavan-3-ols (12%), and isoflavones (9%). Although evidence of publication bias was detected, adjustment using the trim-and-fill method yielded a consistent finding, showing a 13% overall reduction in risk (RR: 0.87; 95% CI: 0.83–0.92; I²: 64%).

Conclusion: Our findings support the protective role of dietary polyphenols against DSCs, particularly flavonols and quercetin, suggesting that further investigations into the optimal intake levels and mechanisms of action are needed. 

Disclosure of Interest: None declared