Plant-based flavonoids may cut ovarian cancer risk

NEW YORK (Reuters Health) - High consumption of two types of flavonoids -- antioxidant chemicals found in plant foods -- may help protect women from ovarian cancer, research from Italy suggests.

Dr. Maria Rossi, of Istituto di Ricerche Farmacologiche "Mario Negri" in Milan, and her colleagues found that the women who took in the most isoflavones and flavonols were the least likely to have ovarian cancer.

"On the basis of our findings and the relevant literature, we infer that isoflavones, and perhaps flavonols, may have favorable effects with respect to ovarian cancer risk," they conclude.

Lab studies suggest flavonoids may also have cancer fighting properties in addition to their antioxidant effects, Rossi and her team note in the International Journal of Cancer.

The researchers compared flavonoid intake for 1,031 women diagnosed with epithelial ovarian cancer and 2,411 women who had been hospitalized for acute, non-cancer-related conditions, categorizing them into five groups based on their intake of each of six different flavonoids.

After the researchers controlled for birth control pill use, number of children the women had, family cancer history and other relevant factors, they found that the women with the highest flavonol intake were 37 percent less likely to have ovarian cancer than women with the lowest flavonol intake.

High intake of isoflavones cut ovarian cancer risk by 49 percent.

The researchers found no relationship between intake of the other four flavonoid types, or total flavonoid intake, and ovarian cancer risk.

Isoflavones are found in tea and soy foods, both of which have been linked to a lower ovarian cancer risk, possibly due to isoflavones' estrogen-blocking effects, Rossi and her colleagues note.

Flavonols are found in many fruits and vegetables, they add. Adjusting the findings for women's fruit and vegetable intake didn't change the relationship between flavonol intake and ovarian cancer risk, the researchers note, suggesting that "flavonols may have a distinct role in explaining the effect of fruit and vegetable against ovarian cancer."