Green and black tea consumption and risk of breast cancer: a systematic review and meta-analysis of prospective cohort studies

Background: Breast cancer risk may be influenced by dietary factors. Green and black teas contain bioactive polyphenols that may have anticancer properties, but epidemiological evidence regarding their association with breast cancer risk remains inconsistent.Objectives: To systematically review and meta-analyse prospective cohort studies evaluating the association between green and black tea consumption and breast cancer risk, including by menopausal status.Methods: PubMed, Scopus and Web of Science were searched from inception through July 1, 2026, to identify prospective cohort studies assessing the association between green or black tea consumption and breast cancer risk. Relative risks and 95% confidence intervals were pooled using random-effects models. Heterogeneity was assessed with the I2 statistic, and subgroup, sensitivity and publication-bias analyses were conducted.Results: Twenty-two cohort studies, providing 41 effect sizes, were included. Overall, tea consumption was not significantly associated with breast cancer risk (pooled effect size [ES] = 1.01, 95% CI: 0.97–1.06, p = 0.518; I2 = 18.7%). Subgroup analysis by tea type showed no significant association for black tea (ES = 1.03, 95% CI: 0.97–1.09) or green tea (ES = 0.96, 95% CI: 0.88–1.04). No significant association was observed among premenopausal (ES = 1.03, 95% CI: 0.92–1.16) or postmenopausal women (ES = 1.07, 95% CI: 0.96–1.20), regardless of follow-up duration. Sensitivity analysis confirmed the robustness of these null findings, and no evidence of publication bias was detected (Egger’s p = 0.193; Begg’s p = 0.711).Conclusion: Tea consumption is not associated with breast cancer risk in either premenopausal or postmenopausal women. These findings do not support either a protective or a harmful association between green or black tea consumption and breast cancer risk and should be regarded as reassuring rather than as a basis for specific dietary or public health recommendations.