Researchers used data from the Health Professionals Follow-Up Study to assess associations between post-diagnosis dietary fat intake and mortality among men with nonmetastatic prostate cancer. The analysis included nearly 5,000 men diagnosed over a 32-year span. Participants had a mean age at diagnosis of about 70 years, and the median follow-up after diagnosis was 12.8 years. Every four years the men completed dietary questionnaires reporting food intake over the previous year; researchers used those reports to estimate consumption of different fat types.
Deaths from any cause were recorded and categorized as deaths from prostate cancer, cardiovascular disease, other cancers, or other causes. The investigators adjusted statistical models for potential confounders including age, cancer treatment, body mass index (BMI), and lifestyle behaviors.
The team estimated intake of saturated, monounsaturated, polyunsaturated, and trans fats. They also categorized fats by their source — whether predominantly from animal foods (for example, red meat, butter, full-fat dairy) or plant foods (for example, olive oil, nuts, seeds). Monounsaturated and polyunsaturated fats were framed as the heart-healthier options in the analysis. The investigators then examined absolute intake and substitution scenarios, assessing associations when calories from one fat type or source were replaced with another.
During follow-up, 3,040 participants died. Of those deaths, 803 were from cardiovascular disease, 499 from cancers other than prostate cancer, and 441 from prostate cancer.
Men with the highest intake of saturated fat had a 24% greater risk of death from any cause compared with men with the lowest saturated fat intake. The highest saturated fat consumers also had a 42% greater risk of dying from cardiovascular disease.
In substitution analyses, replacing 10% of total daily calories from animal fat with plant-based fat was associated with a 16% lower risk of death from any cause. Replacing saturated fat with monounsaturated fat was linked to a 20% lower risk of death from any cause. The investigators reported no association between any of the dietary fat categories studied and prostate cancer–specific mortality.
These findings suggest that the source and composition of dietary fat after a nonmetastatic prostate cancer diagnosis are associated with long-term risks of cardiovascular and non-prostate cancer mortality and overall survival.
Study author Lorelei Mucci, ScD, MPH, noted several biological pathways that may act together to explain the associations. The investigators highlighted potential roles for systemic inflammation, effects on LDL cholesterol, altered metabolism, and processes that lead to atherosclerosis. The authors also referenced prior work in the same cohort linking healthy overall dietary patterns with lower mortality, suggesting fat composition is one component among broader dietary and metabolic influences.
The article notes that plant-based foods are associated with lower inflammatory biomarkers and improved insulin and metabolic measures, which could contribute to lower cardiovascular and other-cause mortality observed when plant fats replace animal fats.
Clinicians quoted in the report framed the results as support for a plant-forward dietary approach rather than an endorsement of strict veganism. A plant-forward hierarchy emphasizes making healthy fats and plant foods the primary elements of meals and reducing reliance on red meat and high-saturated-fat dairy.
Practical features of this approach include choosing olive oil, avocados, nuts, and seeds as primary fat sources, increasing fiber-rich foods that provide beneficial compounds (for example, lycopene and isoflavones), and favoring patterns that support a healthy gut microbiome and metabolic profile. These measures align with cardiovascular risk reduction and may improve long-term survival among prostate cancer survivors where non-prostate causes of death are common.
Experts emphasized that the study’s strengths include its large cohort and lengthy follow-up. However, because the study is observational, it cannot establish causation; unmeasured or residual confounding may influence results. One clinician quoted in the article advised that the evidence alone should not compel a major change in clinical practice but that diet remains an important component of cardiovascular health and longevity.
The article underscores that the associations observed were driven primarily by reductions in cardiovascular and other non-prostate cancer deaths rather than prostate cancer–specific mortality. Overall, the findings support favoring unsaturated plant fats over saturated animal fats as part of survivorship care that addresses cardiovascular and metabolic health.