Patients with nonmetastatic prostate cancer who consumed higher quantities of saturated fats, including animal fats, had a higher risk of all-cause mortality, including death from cardiovascular disease and other cancer, according to the results of a study published in JAMA Network Open.
“Our findings suggest that diet after diagnosis may be one modifiable component of survivorship care, broadening the focus beyond control of the original tumor. Protecting cardiovascular and overall health is an essential part of prostate cancer care, particularly because some treatments can affect metabolic and cardiovascular health,” said co-senior author Lorelei A. Mucci, ScD, MPH, Professor of Epidemiology at Harvard Chan School.
Study Methods
Researchers conducted a cohort study of 4,884 patients with nonmetastatic prostate cancer, from the Health Professionals Follow-Up Study, to determine how postdiagnostic dietary fat intake impacted long-term survival. Patients were diagnosed between 1986 and January 2019, and were followed through December 2022, for a median of 12.8 years.
Dietary data were collected every 4 years via validated food frequency questionnaires, which were used to estimate the patient's intake of saturated, polyunsaturated, monounsaturated, trans, plant, and animal fat after their cancer diagnosis.
The primary outcome measures were all-cause mortality and death from prostate cancer, other cancers, cardiovascular disease, and other causes.
Key Findings
During follow-up, 62% of patients died from any cause.
Patients in the highest quintile of saturated fat consumption had greater all-cause (hazard ratio [HR] = 1.24; 95% confidence interval [CI] = 1.05–1.47), cardiovascular (HR = 1.42; 95% CI = 1.02–1.98), and other cancer mortality (HR = 1.42; 95% CI = 0.93–2.17) compared with patients in the lowest quintile of saturated fat consumption.
Consumption of animal fat was particularly positively associated with all-cause mortality (HR = 1.14; 95% CI = 0.97–1.33) and death from other cancers (HR = 1.49; 95% CI = 1.00–2.21). When patients replaced 10% of their animal fat–related calories with plant-based fats (HR = 0.84; 95% CI = 0.76–0.93) and replaced 5% of saturated fat–related calories with monosatured fats (HR = 0.80; 95% CI = 0.70–0.91), this was associated with a decrease in all-cause mortality.
“The central message is not simply to ‘eat less fat.’ Rather, the type and source of fat appear to matter. Replacing some animal fats and saturated fats with plant-based and unsaturated fats may help support long-term health after a prostate cancer diagnosis,” said co-senior author David P. Labbé, PhD, scientist in the Cancer Research Program at The Institute and Associate Professor in the Department of Surgery at McGill University.
“The takeaway is to prioritize simple substitutions—choosing olive oil, nuts, seeds, avocados and other plant-based foods more often instead of foods high in animal or saturated fat,” said co-senior author Edward L. Giovannucci, MD, ScD, Professor of Nutrition and Epidemiology at Harvard Chan School.
The researchers found no associations between dietary fats and prostate cancer–related mortality.
“Ultimately, our goal is to make nutrition a more precise and evidence-based component of prostate cancer care—one that takes into account the treatment received, tumor biology, and each patient’s cardiovascular and metabolic health,” Dr. Labbé added.
DISCLOSURES: This project was supported in part by funding from the Congressionally Directed Medical Research Programs. The Health Professionals Follow-up Study was supported by funding from the National Institutes of Health. For full disclosures of the study authors, visit jamanetwork.com.
