Breast, ovary and endometrial cancers

Coffee and breast cancer

Overall, research to date has not linked coffee consumption to an increased risk of breast cancer. However, data inpre-menopausal women who are regular coffee drinkers suggests a potential inverse association^52,53. The International Agency for Cancer Research (IARC) 2016 review concluded that studies show either no association, or a modest inverse association, between breast cancer risk and coffee consumption¹. 

The World Cancer Research Fund (WCRF) 2018 Breast Cancer Report does not mention coffee as a risk factor⁵⁴. Variable resultshave been observed, associated with different genetic mutations. Clearly further research is required to clarify the detail in this area, since integrating individual genetic variability when assessing diet-disease associations is likely to be important.

• A 2021 meta-analysis and dose response found a negative correlation between coffee intake and breast cancer risk, especially in post-menopausal and European women⁵²

• A 2021 narrative view of coffee consumption and breast cancer risk in the general population concluded that there is no evidence of an association between coffee intake and breast cancer risk, however there may be a slight reduced risk. In postmenopausal women, and in those carrying the BRCA1 mutation, coffee is inversely associated with breast cancer risk. The effects of coffee in other sub groups is less clear and needs further investigation⁵³

‍

Post-menopausal women

Studies have shown no association between coffee consumption and the incidence of breast cancer in post-menopausal women^53,55,56, with more recent research suggesting a potentially lower risk.

• A 2021 systematic review concluded that a low coffee intake (2-3 cups per day) and high dose tea intake (>5 cups per day) is associated with a potentially lower risk of overall breast cancer and specifically oestrogen receptor breast cancer in post-menopausal women⁵⁵

• A 2021 meta-analysis of 26 studies suggested a negative correlation between coffee consumption and breast cancer risk, especially in post-menopausal and European women⁵⁶

‍

Coffee and ovarian cancer

Ovarian cancer is the fifth most common and lethal cancerin European women¹². Research to date has shown no conclusive association between coffee consumption and risk of ovarian cancer^57,58. The WCRF 2018 Ovarian Cancer Report lists coffee under ‘limited evidence - no conclusion’⁵⁹, and IARC’s 2016 review also concluded that there is inadequate evidence to suggest an association between coffee consumption andovarian cancer¹.

• A 2019 dose response meta-analysis found no association between the risk of ovarian cancer and coffee consumption (caffeinated or decaffeinated), and caffeine intake⁵⁷

• A further 2019 systematic review and meta-analysis concluded that there was no association between total caffeine intake and ovarian cancer risk. However, the authors did find an inverse association between decaffeinated coffee consumption and the risk of ovarian cancer⁵⁸

‍

Coffee and endometrial cancer

The majority of data available suggests that coffee consumption is linked to a lower risk of endometrial cancer^60-62. IARC’s 2016 review found that many epidemiological studies showed reduced risks for cancers of the uterine endometrium¹. The WCRF Endometrial Cancer Report lists coffee under a probable decrease in risk, and mentions that the effect is found in both caffeinated and decaffeinated coffee, and cannot be attributed to caffeine⁶³.

• A 2018 meta-analysis of 12 cohort studies and eight case-control studies, with 11,663 participants and 2,746 endometrial cancer cases, concluded there was an inverse association between coffee consumption and the risk of endometrial cancer. In particular that increased coffee intake might be beneficial for women with obesity⁶⁰

• A 2022 meta-analysis of 24 studies suggested a 29% reduction in endometrial cancer risk when comparing the highest versus the lowest categories of coffee intake. This inverse association was stronger in caffeinated coffee drinkers, those with higher BMI, non-smokers and users of HRT⁶¹. Similar results were presented in a further 2022 pooled analysis, which also suggested a stronger association in participants with higher BMI⁶²