Flavonols may reduce colorectal cancer risk

An increased intake of antioxidant flavonols from tea, onions, beans, and apples may slash the risk of colorectal cancer by a whopping 76 per cent, according to findings published in this month's Cancer Epidemiology Biomarkers & Prevention.

The study adds to a growing body of science linking increased consumption of flavonol-rich foods, such as fruit and vegetables, to risk reductions for a range of cancers, including lung, pancreatic, and breast cancer.

Flavonoids, found in certain wine, fruits, vegetables, tea, nuts, and chocolate, have received extensive research due to their potent antioxidant activity and purported health benefits. Many have also been implicated in possible protection against diseases such as cancer and cardiovascular disease.

The researchers, led by Gerd Bobe from the National Cancer Institute, used data from the flavonoid database from the US Department of Agriculture to quantify the intake of 29 individual flavonoids, total flavonoids, and six flavonoid subgroups among participants of the Polyp Prevention Trial.

The trial studied the effect of a low-fat, high fibre diet, rich in fruit and vegetables on the recurrence of pre-cancerous polyps in the colon and rectum. Over 2,000 men and women were randomly assigned to either the 'healthy' diet, or a normal diet.

Using food frequency questionnaires, Bobe and co-workers analysed dietary consumption of the polyphenols, and, after adjusting for potential confounding factors such as age, fibre intake, BMI, sex, and the use of regular non-steroidal anti-inflammatory medication, they found that an increased intake of flavonols was linked to a 76 per cent reduction in the recurrence of advanced tumors.