Dietary flavonoid and lignan intake and gastric adenocarcinoma risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

Several experimental studies have suggested potential anticarcinogenic effects of flavonoids, although epidemiologic evidence for the impact of dietary flavonoids on risk of gastric cancer (GC) is limited. We investigated the association between intake of dietary flavonoids and lignans and incident GC. The study followed 477,312 subjects (29.8% men) aged 35-70 y from 10 European countries who participated in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Validated dietary questionnaires and lifestyle information were collected at baseline. A food-composition database on flavonoids and lignans was compiled by using data from USDA and Phenol-Explorer databases. During an average follow-up of 11 y, 683 incident GC cases (57.8% men) were mostly validated by a panel of pathologists and used in this analysis. We observed a significant inverse association between total flavonoid intake and GC risk in women (HR: 0.81; 95% CI: 0.70, 0.94; for the continuous variable after log₂ transformation) but not in men (HR: 0.97; 95% CI: 0.85, 1.09). In women, significant inverse associations with GC risk were also observed for intakes of some flavonoid subgroups (anthocyanidins, flavonols, flavones, and flavanols), particularly with intestinal type tumors for total flavonoid and flavanol intakes (P-heterogeneity < 0.1). After stratification by smoking status and sex, there was no significant heterogeneity in these associations between ever- and never-smokers. Total dietary flavonoid intake is associated with a significant reduction in the risk of GC in women.