Does this diet help prevent prostate cancer?

A new study says men who followed a Mediterranean diet - one with an emphasis on fish, boiled potatoes, fruits, vegetables, legumes and olive oil - could lower their risk of aggressive prostate cancer.

But one urologist isn't so sure, and advises people to stick to what science knows works.

Prostate cancer is the most common type of cancer in men, with about one in seven facing the diagnosis in their lifetime, and can have a high mortality rate, according to the American Urological Association.

Prostate cancer cells can then spread from a prostate tumor, according to the association, traveling through blood vessels or lymph nodes to reach other parts of the body. After spreading, cancer cells may attach to other tissues and grow to form new tumors.

The scientific community agrees on several possible risk factors, including:

• Age - Prostate cancer is rarely found in men younger than 40;

• Ethnicity - African American men have the largest incidence of the disease, with one in five developing it across their lifetime, and are more likely to get it at an earlier age and in more aggressive forms;

• Family history - Men with a family history of prostate cancer are two to three times more likely to get it if his father, brother or son had it;

• Smoking - The risk may double for heavy smokers, though within 10 years of quitting your risk decreases to that of a nonsmoker of the same age;

• World area - Residents of North America and Northern Europe have a higher rate of diagnosis, though the reason for the correlation is unclear.

It is believed that there may be some tie between diet and prostate cancer, but Dr. Laurie Bachrach, urologist at Advocate Good Samaritan Hospital in Downers Grove, Ill., says the connection is unclear, and the study doesn't do a good job of proving one.

The study, published in "The Journal of Urology" and conducted by the Spanish National Center for Epidemiology in Madrid, compared the Mediterranean diet to the Prudent diet (low-fat dairy, whole grains, fruits, vegetables and juices) and Western diet (fatty dairy products, refined grains, processed meat, caloric beverages, sweets, fast food and sauces).

However, its scope was limited to a relatively small geographic area - a few regions in Spain - and didn't take into account genetic and other personal risks, Dr. Bachrach says.

"Unfortunately, there have been a lot of studies on diet and supplementation that have been very promising and been debunked later," she says. "That's one of the things that's frustrating about it - like breast cancer, there's not a whole lot patients can do in terms of changing their habits to prevent it."

Essentially, the various risk factors that seem to play a role in the development of prostate cancer must either be included or controlled for in any study on the cancer.

However, both Dr. Bachrach and the American Urological Foundation say there are some studies that link "heart healthy" activities - eating right, exercising, watching your weight and not smoking - can help avoid prostate cancer. There have also been a few drugs that may prevent or slow the development of the cancer.

But for now, Dr. Bachrach says early detection through annual prostate exams starting at age 50 was still the best bet.

"Keeping up with your screening is probably your best bet in terms of being able to catch prostate cancer early and prevent it from spreading," she says.