McLean, Va. – Fellas, take note: An apple a day just might keep the urologist away.

Researchers at the Mayo Clinic in Rochester, Minn., report that quercetin – a plant-based nutrient found most abundantly in apples, onions, tea and red wine – may provide a new method for preventing or treating prostate cancer.

Mayo Clinic researchers found in a laboratory study that quercetin reduced or prevented the growth of human prostate cancer cells by blocking activity of androgen hormones. Previous research has linked androgens to prostate cancer’s development and progression.

"By blocking androgen activity, the growth of prostate cancer cells can be prevented or stopped," said Nianzeng Xing, Ph.D., the Mayo Clinic’s lead researcher on this project, in a Mayo Clinic press release. "Our study suggests quercetin may be a potential non-hormonal approach to preventing or treating prostate cancer."

The Mayo Clinic research is hopeful news in the battle against prostate cancer, a serious threat to male health. Prostate cancer is the most common cancer in men and the second leading cause of cancer death in men in the United States, behind only lung cancer, according to the American Cancer Society. It strikes silently, usually causing no symptoms until it reaches an advanced stage, and can spread to bone, kidneys and brain. The most common treatment for advanced prostate cancer is castration.

The American Cancer Society estimates that nearly 200,000 men will be diagnosed with prostate cancer, and that 31,500 will die of it this year alone in the United States.

The Mayo Clinic study was published in the March edition of the peer-reviewed journal Carcinogenesis, and was presented late last month at the American Association of Cancer Research annual meeting. The study was partly funded by a grant from the National Institutes of Health. The next step would be to seek to validate the laboratory findings in an animal study.

Quercetin: A Wonder Nutrient?
Quercetin may prove to be a wonder nutrient. In addition to the Mayo Clinic prostate cancer study findings, quercetin has also been linked to a reduced risk of lung cancer. Researchers at the University of Hawaii reported in the Journal of the National Cancer Institute last January that increased consumption of quercetin from food was associated with a reduced risk of lung cancer, based on their study of 1,200 people. Finnish researchers had drawn the same conclusion after studying nearly 10,000 men for 24 years in a report published in the American Journal of Epidemiology in August 1997.

The Mayo Clinic study is the latest addition to a growing body of research evidence linking apple nutrients with a notable range of health benefits. Cornell University researchers reported in the journal Nature in June 2000 on laboratory research finding that apple antioxidants inhibit the growth of certain types of cancer cells. In addition to the Hawaii and Finnish lung cancer findings, other recent population studies have associated apples with improved lung function, reduced risk of certain types of stroke and reduced risk of coronary mortality, often attributed to the plant-based nutrients found in apples.

The U.S. Apple Association (USApple) is the national trade association representing all segments of the apple industry. Members include 40 state apple associations representing 9,000 apple growers throughout the country, as well as nearly 500 individual firms involved in the apple business. USApple’s mission is to provide the means for all segments of the U.S. apple industry to join in appropriate collective efforts to profitably produce and market apples and apple products.