Men with early stage prostate cancer may live longer if they eat a diet rich in heart-healthy nuts, vegetable oils, seeds and avocados, researchers said.
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. The study, published in JAMA Internal Medicine, is the first to analyze fat consumption after diagnosis and the risk of death.
There are several possible explanations for why healthy fats may slow the progression of prostate cancer and boost survival, said lead researcher Erin Richman, a post-doctoral scholar at the University of California, San Francisco. Nuts and vegetable oils increase levels of antioxidants, which protect against cell damage, and reduce inflammation and oxidative stress that's related to aging, she said.
"Based on this study, combined with extensive literature on cardiovascular disease, it's appropriate to recommend that men with prostate cancer consume a heart healthy diet with unsaturated fats that comes from nuts, healthy oils like olive and canola, seeds and avocados," she said. "I don't think we need more research to make the recommendation, though we do need it to better understand the biology of prostate cancer."
Unsaturated fats are heart healthy, and previous research shows they also help patients with advanced prostate cancer.
While 1 in 6 men will be diagnosed with prostate cancer, making it the most common type of tumor, most don't die from it. There are currently 2.5 million men living in the U.S. with the cancer today, according to the American Cancer Society.
The researchers examined men participating in the Health Professionals Follow-up Study who were diagnosed with prostate tumors between 1986 and 2010. During the quarter-century of research, 1,064 men died, mainly from heart disease.
Those who reported eating an additional serving of oil- based dressing each day were 29 percent less likely to die from prostate cancer, with a 13 percent lower risk of dying from any causes. A daily serving of nuts cut prostate cancer death by 18 percent and death from any cause by 11 percent.
The research isn't a randomized trial and doesn't conclusively prove that men with early stage prostate cancer can reduce their risk of dying by changing their diet, wrote Stephen Freedland, from Duke University Medical Center in Durham, in an editorial. The only proven link to death from prostate cancer is obesity, he said.
"Avoiding obesity is essential," he wrote. "Exactly how this should be done remains unclear."
The data suggest that substituting healthy foods such as vegetable fats for unhealthy foods, such as carbohydrates may have a benefit, he said.