Consuming more plant-based food reduces risk for prostate cancer progression
Key takeaways:
- Men who had diets rich in plant-based foods had lower risk for prostate cancer progression.
- No statistical difference occurred in prostate-specific cancer mortality.
Men with nonmetastatic prostate cancer who ate more plant-based foods experienced significantly lower risk for disease progression compared with individuals who ate lower quantities, according to study data published in JAMA Network Open.
Those in the top quintile of plant-based diets consumed a mean of four more servings combined of vegetables, fruit and whole grains per day than those in the bottom quintile, study investigators reported.
“While not all diets are equal in terms of modifiable risk factors for prostate cancer progression, these results could guide people to make better, more healthful choices across their whole diet rather than adding [or]removing select foods,” Vivian N. Liu, MAS, clinical research lead at MANUAL, London, and clinical research coordinator at University of California, San Francisco, told Healio.
Background and methodology
Healio previously reported on the quality-of-life benefits plant-based diets could have on men with prostate cancer and lower risk for recurrence.
“Yet, little is known about plant-based dietary patterns and prostate cancer-specific clinical outcomes after diagnosis,” Liu and colleagues wrote.
“Progressing to advanced disease is one of many pivotal concerns among patients with prostate cancer, their family and caregivers, and their physicians,” Liu told Healio. “Given the growing interest in plant-based food at the population level, examining whether dietary patterns are associated with prostate cancer is an important topic of research and may be more biologically meaningful than studying the association of individual foods.”
Researchers conducted a longitudinal observational study to investigate.
The analysis included men with stage IIIA or lower nonmetastatic prostate cancer who had taken part in the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) study.
The subset of patients chosen by researchers received a comprehensive diet and lifestyle questionnaire, which included a food frequency questionnaire. Participants received the questionnaire between 2004 and 2016.
The study cohort consisted of 2,062 men (median age at diagnosis, 65 years; 95% white; 57% stage I or lower).
Researchers created 18 different food groups (seven healthful plant foods, six animal foods, five unhealthful plant foods) and scored patient responses based on their intake.
They evaluated time to prostate cancer progression — which included biochemical recurrence, secondary treatment, bone metastasis or death attributable to prostate cancer — as the study’s primary endpoint, with a secondary assessment of prostate cancer-specific mortality.
Results and next steps
After a median follow-up of 6.5 years, researchers observed 190 disease progression events and 61 deaths.
Men who had a plant-based diet score in the top quintile had a 47% lower chance of disease progression compared with those in the lowest quintile.
Those in the highest quintile ate a mean of 1.9 more servings of vegetables, 1.6 fruits and 0.9 whole grains daily than the lowest quintile.
“These findings were in line with our expectations,” Liu said.
“Previous studies have suggested benefits of plant-based diets on various health outcomes, including cardiovascular disease, diabetes and overall mortality,” she added. “Individual plant foods — especially cooked tomatoes, cruciferous vegetables like broccoli and kale, and top food sources of vegetable fats including nuts, avocado and olive oil — have links to prostate-cancer specific outcomes [such as] risk, recurrence and progression.”
Researchers reported no statistically meaningful difference among the highest and lowest healthful plant-based diet groups.
They also did not find statistically significant difference in prostate cancer mortality based on dietary indices, but “confidence intervals were too wide to draw meaningful conclusions from point estimates,” they wrote.
“Doctors could use this study to recommend a shift toward a plant-based diet rich in fruits, vegetables, whole grains, nuts and legumes to improve prostate cancer outcomes and overall health,” Liu said. “Providing guidance on practical ways to incorporate these foods into daily meals and addressing any concerns or barriers patients may have regarding dietary changes may empower patients to make positive lifestyle choices.”
Study limitations included self-reported data on dietary intake, lack of diversity among the study cohort and inability to measure vegan diets’ impact on prostate cancer progression.
Liu said the next steps in research would be to evaluate a more diverse cohort and whether plant-based diets produce the same results in individuals with advanced disease.
“While our study provides insights into the benefits of consuming more plant-based foods and less animal-based foods after a prostate cancer diagnosis, dietary recommendations should be personalized and take into account individual factors such as genetics, metabolism and food preferences,” Liu said.
For more information:
Vivian N. Liu, MAS, can be reached at vvnliu@berkeley.edu.
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Liu VN, et al. JAMA Network Open. 2024;doi:10.1001/jamanetworkopen.2024.9053.