MADRID, Spain — A healthy diet does not guarantee that men will be free of prostate cancer, according to a recent study. At the same time, researchers in Spain also discovered that unhealthy diets significantly increase the risk of aggressive forms of the disease. Their study found that men who regularly consume junk food and sugary drinks are more susceptible to life-threatening tumors.

“Our results indicate that avoiding unhealthy dietary habits could be the best nutritional strategy to prevent aggressive prostate cancer,” says lead author Dr. Adela Castello-Pastor, of the Carlos III Institute of Health in Madrid.

The study followed 15,296 Spanish participants for an average of 17 years. Over 600 prostate cancer cases were diagnosed during the follow-up period.

Diets were categorized as “Western,” “Prudent,” or “Mediterranean.” The Western dietary pattern consisted of high-fat dairy products, processed meats, refined grains, sweets, caloric drinks, convenience food, and sauces, with a low intake of low-fat dairy products and whole grains. Dr. Castello-Pastor explains that milk and other dairy products suppress the production of prostate cancer-fighting chemicals.

The Prudent dietary pattern featured a high intake of low-fat dairy products, vegetables, fruits, whole grains, and juices. Meanwhile, the Mediterranean dietary pattern included high consumption of fish, vegetables, legumes, boiled potatoes, fruits, olives, and vegetable oil, with a low intake of juices.

Those who adhered to a Western-style diet were most likely to develop tumors that spread to other organs.

“Total and saturated fats and trans fatty acids from red and processed meats, sweets, sauces, and convenience food are suspected to enhance PCa (advanced prostate cancer) progression through the disruption of hormonal regulation to increase oxidative stress (that impairs the repair of DNA damage) and inflammation (that increases cellular proliferation),” Dr. Castello-Pastor continues in a media release.

Although adhering to a healthy diet, such as the Prudent and Mediterranean diets, was not enough to prevent prostate cancer entirely, it did reduce the risk of the most aggressive forms of the disease. This is the first study to specifically examine the deadliest tumors associated with prostate cancer.

Prostate cancer is the second leading cause of cancer death in American men, according to the American Cancer Society. About 1 man in 41 will die of the disease.

The study is published in the journal BJU International.

South West News Service writer Mark Waghorn contributed to this report.