Huge 40-year, 180,000 woman cohort shows flavanols can reduce ovarian cancer risk

02-Sep-2014 - By Nicola Cottam
“To our knowledge, this is the first population-based study to suggest a chemopreventive effect for flavanones on ovarian cancer risk..."
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Regular consumption of flavanols and flavanone bioactive compounds, found in tea, citrus fruits and fruit juices, can lower the risk of ovarian cancer by as much as 21%, according to a cohort study involving nearly 180,000 women and begun in 1976.

Six commonly consumed flavonoid subclasses – flavanones, flavonols, anthocyanins, flavan-3-ols, flavones, and polymeric flavonoids – as well as their main food sources, were examined for their association with epithelial ovarian cancer.

Published in the American Journal of Clinical Nutrition, the cohort linked flavanol and flavanone intakes of about 75 milligrams per day (mg/d) with lower risk of ovarian cancer, especially in women aged 30-55 years.

The ‘polymer’ subclass was identified as the main flavonoid group consumed by subjects (at 95.4–274.7mg/d) with a notable link observed between the polymer flavanone ‘proanthocyanidin’ and a ‘low risk’ of fatal tumors, the UK and US team said.

“There was a suggestion that flavanones were more-strongly associated with lower risk of serous (or surface) invasive and poorly differentiated tumors than risk of non serous tumors. Because serous tumors tend to have poorer outcomes, this may have important implications for prevention.”

First population-based study

Flavonoids are present in a variety of foods and drinks, including fruit, vegetables, tea, and wine, but few studies have examined the association between these compounds and ovarian cancer risk.

“To our knowledge, this is the first population-based study to suggest a chemopreventive effect for flavanones on ovarian cancer risk”, they wrote.

Study details

The study involved 171,940 female participants aged 25-to-55 years old. Each subject completed an initial questionnaire to assess risk factors for cancer and cardiovascular disease, along follow-up biennial questionnaires to track subsequent lifestyle factors and disease diagnoses.

Flavonoid intake was validated using food-frequency questionnaires collected every four years.

Oranges and orange juice were found to be the main source of flavonoids among participants and were consumed by 27% and 54% of participants, respectively. Black tea was another major source (in 31% of cases), followed by onions (20%) and apples (10%).

Source: The American Journal of Clinical Nutrition

First published August 20, 2014

‘Intake of dietary flavonoids and risk of epithelial ovarian cancer’

doi: 10.3945/ajcn.114.088708

Authors: Aedin Cassidy, Tianyi Huang, Megan S Rice, Eric B Rimm, Shelley S Tworoger

Related topics: Research, Antioxidants/carotenoids, Polyphenols, Cancer risk reduction

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