Healthier fats linked to longer survival after prostate cancer diagnosis

Study conducted at Harvard T.H. Chan School of Public Health and The Institute finds that replacing saturated and animal fats with unsaturated and plant-based fats is associated with a lower risk of death among men with nonmetastatic prostate cancer.

Men diagnosed with nonmetastatic prostate cancer can generally expect to live for many years after their diagnosis. However, cardiovascular disease and other cancers remain important threats to their long-term health. For many survivors, this raises an important question: What can I do to live a longer, healthier life? A new study published in JAMA Network Open suggests that the type and source of dietary fat they consume may make a difference.

The study, co-led by researchers from the Research Institute of the McGill University Health Centre (The Institute) and Harvard T.H. Chan School of Public Health, included nearly 5000 men with nonmetastatic prostate cancer and followed them for a median of 12.8 years, drawing on data collected over more than three decades. The researchers found that the type and source of fat consumed after diagnosis were associated with long-term survival. Higher saturated fat intake, as well as higher animal fat consumption (a major dietary source of saturated fat) were associated with greater all-cause mortality. These associations were driven primarily by deaths from cardiovascular disease and, to a lesser extent, other cancers—not by prostate cancer itself.

“Our findings suggest that diet after diagnosis may be one modifiable component of survivorship care, broadening the focus beyond control of the original tumour. Protecting cardiovascular and overall health is an essential part of prostate cancer care, particularly because some treatments can affect metabolic and cardiovascular health,” says Prof. Lorelei Mucci, co-senior author of the study, Professor of Epidemiology, Harvard Chan School.

The findings are particularly relevant as the population of prostate cancer survivors continues to grow. Approximately 300,000 men are living with prostate cancer in Canada, while 3.5 million prostate cancer survivors live in the United States. Supporting long-term health after diagnosis is therefore an increasingly important aspect of prostate cancer care. 

The source and type of fat matter

During follow-up, 3,040 participants died. The researcher’s analysis showed that men with the highest saturated-fat intake had a 24% higher rate of death during follow-up than those with the lowest intake. Their estimated 10-year risk of death was 26.4%, compared with 23.4% among men with the lowest intake—a difference of about three deaths per 100 men over 10 years.

The researchers also used statistical models to estimate the potential impact of replacing certain dietary fats with healthier alternatives while keeping overall calorie intake similar. Replacing about 10% of daily calories from animal fat with plant-based fat was associated with a 16% lower rate of death from any cause. Similarly, replacing about 5% of daily calories from saturated fat with monounsaturated fat was associated with a 20% lower rate of death. 

“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,” says Prof. David P. Labbé, Ph.D., co-senior author of the study, Scientist in the Cancer Research Program at The Institute and Associate Professor in the Department of Surgery at McGill University.

The findings are also consistent with studies in people without cancer and with dietary recommendations from the American Heart Association. However, the authors stress that the study shows associations and does not establish cause and effect. The findings should not be interpreted as a recommendation to follow a restrictive diet or eliminate animal products altogether.

“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,” emphasizes Dr. Edward Giovannucci, co-senior author of the study, Professor Nutrition and Epidemiology, Harvard Chan School.

A large prospective study spanning more than three decades 

The study used data from the Health Professionals Follow-Up Study, a long-running prospective study that began in 1986 and has followed more than 50,000 male health professionals across the United States. 

The researchers identified 4,884 participants diagnosed with nonmetastatic prostate cancer between 1986 and January 2019, most of whom were white and were approximately 70 years old at the time of diagnosis. Participants completed detailed, validated food-frequency questionnaires every four years and were followed through December 2022. 

The researchers examined whether the participants’ intake of saturated, monounsaturated, polyunsaturated, trans, animal and plant-based fats was associated with overall mortality or specific causes of death. In their analysis, they accounted for many factors that could influence survival, including age, tumour stage and grade, treatment, smoking, physical activity, body weight and other health conditions. 

Of the 3,040 deaths during follow-up, 803 were from cardiovascular disease, 499 from cancers other than prostate cancer and 441 from prostate cancer.

Toward personalized nutrition in prostate cancer care 

Since the study participants were predominantly white men in the United States, the researchers hope to replicate their findings in more diverse populations. In addition, they plan to further investigate the role of diet after a prostate cancer diagnosis and examine specific foods, individual fatty acids and broader dietary patterns, as well as whether the associations between fat consumption and health outcomes differ according to the treatment patients receive.

“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, tumour biology, and each patient’s cardiovascular and metabolic health,” says Prof. Labbé.

About the study
Dietary Fat Intake and Mortality Among Patients With Nonmetastatic Prostate Cancer by Yiwen Zhang, Megan R. Shanahan, Hannah E. Guard, Jiachen Ji, Maria Celia Fernandez, Nadia Boufaied, Jane B. Vaselkiv, Binkai Liu, Chaoran Ma, Rebecca E. Graff, Stacy Loeb, Caroline Himbert, Yuan Ma, Edward L. Giovannucci, David P. Labbé and Lorelei A. Mucci, is published in JAMA Network Open on September 2, 2026.

DOI:10.1001/jamanetworkopen.2026.30693

This project was supported in part by funding from the Congressionally Directed Medical Research Programs (grant W81XWH-22-1-0585 to David P. Labbé and Lorelei A. Mucci). The Health Professionals Follow-up Study was supported by funding from the National Institutes of Health (U01 167552).

Media contacts

Fabienne Landry
McGill University Health Centre
[email protected]

Maya Brownstein
Harvard T.H. Chan School of Public Health
[email protected]