High intake of saturated and animal fats following a diagnosis of nonmetastatic prostate cancer is associated with increased mortality from cardiovascular disease and other cancers, according to a study. But the good news is that replacing saturated and animal fats with healthier plant-based fats may improve survival outcomes.
“High intake of saturated fat and animal fat is common in Western dietary patterns characterized by consumption of red meat and processed meat, high-fat dairy, and refined grains,” noted researchers led by Dr Yiwen Zhang from the Harvard T.H. Chan School of Public Health, Boston, Massachusetts, US.
“In the US, major dietary saturated fat sources include cheese, pizza, ice cream, milk, and butter; meat products such as sausage, beef, and hamburgers; and cookies, cakes, and other grain-based desserts,” Zhang and colleagues continued.
In their study, the researchers analysed data from 4,884 patients with nonmetastatic prostate cancer (mean age at diagnosis 69.5 years) who participated in the Health Professionals Follow-Up Study. A total of 3,040 deaths from any cause were documented over a median follow-up of 12.8 years.
Zhang and colleagues found that compared with participants in the lowest quintile of postdiagnosis intake of saturated fats, those in the highest quintile had a 24-percent greater risk of all-cause mortality (hazard ratio [HR], 1.24, 95 percent confidence interval [CI], 1.05–1.47). [JAMA Netw Open 2026;9:e2630693]
The excess risk of death associated with saturated fat intake was driven by high incidence of death from cardiovascular disease (HR, 1.42, 95 percent CI, 1.02–1.98) or other cancers (HR, 1.42, 95 percent CI, 0.93–2.17). No significant effect was observed on the incidence of deaths from respiratory conditions, dementia, or neurologic diseases.
Animal fat, a major source of saturated fats, also showed a positive association with all-cause mortality (highest vs lowest intake quintile: HR, 1.14, 95 percent CI, 0.97–1.33), as well as deaths from other cancers (HR, 1.49, 95 percent CI, 1.00–2.21).
Of note, replacing 10 percent of calories from animal fats with plant-based fats conferred a 16-percent reduction in all-cause mortality (HR, 0.84, 95 percent CI, 0.76–0.93). Similarly, replacing 5 percent of calories from saturated fats with monounsaturated fats yielded a 20-percent reduction (HR, 0.80, 95 percent CI, 0.70–0.91).
There were no associations observed between dietary fats and prostate cancer mortality.
“This study, coupled with prior epidemiologic studies, provides evidence-based recommendations for patients and clinicians around dietary fat consumption to improve survivorship outcomes in the clinical setting of nonmetastatic prostate cancer,” according to Zhang and colleagues.
Translation into practice
When providing dietary counselling after a diagnosis of prostate cancer, clinicians should adopt an approach that is neither nihilistic nor overstated, according to Dr David-Dan Nguyen and co-authors in an accompanying editorial. [JAMA Netw Open 2026;9:e2630595]
“Clinicians should not present dietary fat modification as a proven prostate cancer–directed therapy, but neither should they ignore an important opportunity to promote health when patients are motivated to act,” wrote Nguyen and colleagues.
“Among patients with nonmetastatic prostate cancer, cardiovascular disease is a leading and often more common cause of death than prostate cancer itself. Therefore, using the period after diagnosis to improve diet, physical activity, smoking status, and cardiometabolic risk may provide substantial benefits, even without a demonstrated effect on prostate cancer–specific mortality,” they continued.
Nguyen and colleagues emphasized that a prostate cancer diagnosis represents a unique moment to empower patients. Clinicians should leverage this moment to recommend dietary patterns that limit saturated and animal fats and incorporate more plant-based foods and sources of unsaturated fat, alongside regular physical activity, smoking cessation, cardiometabolic risk management, and attention to emotional and social needs, to improve long-term survivorship beyond cancer therapies, they added.