Epithelial ovarian cancer remains a highly lethal malignancy, and to date, few modifiable risk factors have been established. With respect to diet, early ecologic studies suggested that a high plant-based diet that is rich in fruit and vegetables may be related to decreased risk, although subsequent case-control and prospective studies have yielded inconsistent findings. Plants contain bioactive constituents called flavonoids that modulate key cellular signaling pathways and regulate multiple cancer-inflammation pathways and epigenetic cofactors. These compounds have the potential to exert chemopreventive effects, suggesting that flavonoids might be specific components in plants that could reduce ovarian cancer risk. Flavonoids are present in many foods and beverages including fruit, vegetables, and black tea.

The researchers examined the association of 6 flavonoid subclasses, total flavonoid intake, and their main food sources with risk of epithelial ovarian cancer in the Nurses’ Health Study (NHS) and Nurses’ Health Study II (NHSII). In the proclaimed study, dietary habits of 171,940 women aged between 25-55 were studied over the course of 3 decades.  Dietary intake data were assessed in 1984, 1986, and every 4 years thereafter in the NHS. Similar FFQs were initially administered in 1991 and subsequently every 4 years in the NHSII.

According to result of the study, higher intakes of flavonols and flavanones as well as black tea consumption may be associated with lower risk of ovarian cancer. Although the researchers added "Additional prospective studies are required to confirm these findings."

The lead author Prof. Aedin Cassidy, from UEA's Norwich Medical School says:"The main source of these compounds include tea and citrus fruits and juices, which are readily incorporated into the diet, suggesting that simple changes in food intake could have an impact on reducing ovarian cancer risk. In particular, just a couple of cups of black tea every day was associated with a 31% reduction in risk."