Dietary Fat Intake Associated With Mortality After Prostate Cancer

Higher saturated fat consumption after diagnosis was associated with greater all-cause and cardiovascular mortality among men with nonmetastatic prostate cancer in a prospective cohort study published in JAMA Network Open. Dietary substitution models also linked replacing saturated or animal fats with monounsaturated or plant-based fats, respectively, to lower all-cause mortality.

The analysis included 4,884 Health Professionals Follow-Up Study participants diagnosed with nonmetastatic prostate cancer from 1986 through January 2019 and followed through December 2022. Dietary intake was measured every 4 years using validated semiquantitative food frequency questionnaires; postdiagnosis intake came from the first eligible questionnaire returned at least 6 months after diagnosis. Multivariable Cox models accounted for demographic, clinical, and lifestyle factors.

Over a median 12.8 years, 3,040 deaths occurred: 441 from prostate cancer, 499 from other cancers, and 803 from cardiovascular disease. Comparing the highest with the lowest saturated fat quintile, the adjusted hazard ratio (HR) was 1.24 (95% CI, 1.05-1.47) for all-cause mortality and 1.42 (95% CI, 1.02-1.98) for cardiovascular mortality. The estimate for mortality from other cancers was also elevated (HR, 1.42; 95% CI, 0.93-2.17), although the confidence interval included the possibility of no difference.

Replacing 10% of calories from animal fats with plant-based fats was associated with lower all-cause mortality (HR, 0.84; 95% CI, 0.76-0.93). Replacing 5% of calories from saturated fats with monounsaturated fats was also associated with lower all-cause mortality (HR, 0.80; 95% CI, 0.70-0.91). Dietary fat intake was not associated with prostate cancer mortality.

The authors noted that the observational design left potential for residual confounding. Postdiagnosis diet was based on one eligible questionnaire and was not updated, potentially misclassifying exposure if diets changed during follow-up. The predominantly White, health-professional cohort may limit generalizability to more racially, ethnically, and socioeconomically diverse populations.

Source: Zhang Y, Shanahan MR, Guard HE, et al. Dietary fat intake and mortality among patients with nonmetastatic prostate cancer. JAMA Netw Open. 2026;9(9):e2630693. doi:10.1001/jamanetworkopen.2026.30693