Feb. 15, 2008 (San Francisco) -- Men: Take off the skin!
That's the advice of U.S. researchers who found that poultry and eggs double the risk of prostate cancer progression.
"But when we broke it down, the increased risk was confined to poultry with the skin on and eggs," says June M. Chan, ScD, of the University of California, San Francisco.
The study of about 1,250 men treated for prostate cancer also showed that orange and yellow vegetables, such as squash, yams, and carrots, and cruciferous vegetables, such as broccoli, cut the risk of recurrence by about half.
Fruit and fish did not appear to help prevent prostate cancer from returning, Chan tells WebMD.
The study results were based on data from CaPSURE, a national registry of men with prostate cancer.
Though the findings need to be confirmed in other studies, Chan says that they held up even after the researchers took into account other factors -- such as age, weight, and exercise -- that can affect prostate cancer risks.
"If you eat chicken or poultry, eat it without the skin," she advises.
Pomegranate Juice Protective
The study was presented at the Genitourinary Cancers Symposium, presented by the American Society of Clinical Oncology (ASCO) and two other cancer care organizations.
Other research reported at the meeting pointed to the benefits of pomegranate juice and lycopene in preventing prostate cancer progression.
UCLA researcher Allan Pantuck, MD, and colleagues enrolled 46 men in a study funded by the owners of POM Wonderful Co., the maker of the pomegranate juice used in the study. The men all had rising PSA (prostate-specific antigen) levels after cancer treatment; all drank 8 ounces of pomegranate juice every day.
Original results of the study, published in 2006, showed that the men's overall PSA doubling time was nearly four times slower after they began drinking pomegranate juice.
Pantuck says that when the study was scheduled to end, a lot of the men didn't want to give up the pomegranate juice. So its design was amended and men were allowed to continue consuming their purple drink.
As of August 2007, 17 men had been followed for an average of 58 months. Their PSA doubling time is now nearly five times slower than before they started drinking the juice, Pantuck tells WebMD.
"There's a very durable improvement," he says.
Tomatoes Fight Prostate Cancer
A third study presented at the meeting suggests that lycopene -- an antioxidant found mainly in tomatoes and tomato products -- can cut the chance that prostate cancer will spread.
The researchers gave 45 men with cancer confined to the prostate either no supplement or lycopene supplements for four to six weeks. The supplements contained 15, 30, or 45 milligrams of lycopene.
While the study was too short to determine if lycopene lowered PSA, "we did see evidence that lycopene, at both the 30-milligram and 45-milligram doses slows cell proliferation," says researcher Nagi Kumar, RD, of the Moffitt Cancer Center in Tampa. Cell proliferation is a sign of tumor growth and spread.
Last year, a major study of lycopene in 28,000 men made headlines when it showed that lycopene had little impact on prostate cancer risk.
It contradicted earlier research suggesting a protective role for lycopene.
Chan says that she's still a believer. "My reading of the literature is that on balance, lycopene-rich products such are tomatoes are likely to have benefit," she tells WebMD.
ASCO spokesman Alan Pollack, MD, PhD, a prostate cancer specialist at Fox Chase Cancer Center in Philadelphia, stresses the importance of a balanced diet.
"I generally tell my patients, 'What is good for your heart is good for your prostate,'" he says.