A set of six healthy habits, including eating more tomatoes and less processed red meat, helped men reduce their risk of dying from prostate cancer, a study found.
Researchers analyzed information gathered from almost 46,000 men for 25 years and found that those who adopted five or six of the habits had a 39 percent lower risk of developing lethal prostate cancer than those who adopted one or none of the habits, according to the results presented at the European Cancer Congress in Amsterdam on Sunday. In another study involving more than 21,000 men, the risk reduction was 47 percent.
Each of the six habits, which also included not smoking, exercising, eating fatty fish and having a body-mass index of less than 30, has been linked with lowering prostate cancer risk, but their joint effect hasn't been studied before, said Stacey Kenfield, a University of California, San Francisco, researcher who presented the results. The scientists are now studying which elements play the most important role in reducing cancer risk, she said.
"Encouraging men and counseling men to adopt these six factors will likely improve their overall health and hopefully also improve their prostate-cancer risk," Kenfield said in the presentation. "Our data suggest that adopting these practices may prevent a large proportion of lethal prostate cancer."
While one in six men will be diagnosed with prostate cancer, making it the most common type of tumor, most don't die from it. There are 2.5 million men living in the U.S. with prostate cancer, according to the American Cancer Society.
Tomatoes contain lycopene, an antioxidant that can block the action of cell-damaging free radicals, according to the society's website.
In one of the two studies, men who only adopted the dietary habits had a 27 percent lower risk of lethal prostate cancer than those who adopted none. In the other study, the risk reduction was 48 percent.
"Genes load the gun but lifestyle pulls the trigger," Axel Heidenreich, director of urology at the University Hospital Aachen in Germany, said in comments following Kenfield's presentation. "There is definitely some impact from diet on the progression of prostate cancer."
Men with early-stage prostate cancer may live longer if they eat a diet rich in heart-healthy nuts, vegetable oils, seeds and avocados, the same group of researchers said in June.
Their analysis of 4,577 men found those who reported eating vegetable fats were less likely to develop fatal tumors or die from other causes than those with diets high in animal fats and carbohydrates.
A separate study presented in Amsterdam on Monday found that a test commonly used to detect prostate cancer does more harm than good. For every 1,000 men who have a prostate-specific antigen test, or PSA, one death is prevented and 12 additional cases of impotence and three cases of incontinence are caused by unnecessary surgery, Mathieu Boniol, research director at the International Prevention Research Institute in Lyon, France, said at a briefing with reporters.
The American Urological Association in May dropped its recommendation that men over the age of 40 consider getting a PSA test.