Men with prostate cancer had a lower risk of dying from the disease if they increased their consumption of vegetable fat, nuts and olive oil, a new study suggests.

The study, published online in the Journal of the American Medical Association (JAMA) Internal Medicine, found that men who followed some simple dietary improvements can effectively lower their death risk after being diagnosed with prostate cancer.

Nuts and vegetable oils (such olive and canola oil) were the 2 sources of vegetable fats associated with reduced overall and disease-specific mortality.

"Consumption of healthy oils and nuts increases plasma antioxidants and reduces insulin and inflammation, which may deter prostate cancer progression," said lead author Erin Richman, a postdoctoral scholar in the University of California San Francisco Department of Epidemiology and Biostatistics.

"The potential benefit of vegetable fat consumption for prostate cancer-specific outcomes merits further research," he added.

The US authors stressed the research involving 4,577 prostate cancer patients had revealed an association and not a causal link.

Of the male health workers with prostate cancer enrolled into the Health Professionals Follow-up Study, around a fifth (21%) died from the disease over a period of about eight years. Another 31 per cent died from heart disease and almost 21% from other cancers.

The study compared the highest versus the lowest quintile of fat intake, they found the following rates of lethal prostate cancer per 1,000 person-years:

  • Saturated -- 7.6 versus 7.3
  • Monounsaturated -- 6.4 versus 7.2
  • Polyunsaturated -- 5.8 versus 8.2
  • Trans-- 8.7 versus 6.1
  • Animal -- 8.3 versus 5.7
  • Vegetable -- 4.7 versus 8.7

"Men who consumed more vegetable fat after diagnosis had a lower risk of lethal prostate cancer," the authors said. "Replacing 10% of calories from carbohydrates with vegetable fat was associated with a 29% lower risk of lethal prostate cancer. The magnitude of the association was similar, but not statistically significant, when animal fat was replaced with vegetable fat (HR 0.76, 95% CI 0.52-1.10).