Mediterranean Diet Might Benefit Low-Risk Prostate Cancer Patients

A recent study from the University of Texas MD Anderson Cancer Center found that men with localized prostate cancer on active surveillance might benefit from following a Mediterranean-style diet over the course of their disease.¹

The Mediterranean diet emphasizes eating plenty of vegetables; getting protein from sources like fish, poultry, beans, and eggs; eating moderate portions of dairy; and limiting red meat consumption. The study, published in the journal Cancer, homed in on the diet as a potentially outcome-changing eating strategy because it has been shown to have an array of protective effects when followed consistently. Research has linked the Mediterranean diet to many potential health benefits, including a lower risk of heart disease, lower cholesterol and blood pressure, and even a decreased risk of developing cancer.^2-4

To find out whether the Mediterranean diet might benefit men with localized prostate cancer, researchers had 410 patients with newly diagnosed prostate cancer on active surveillance complete a baseline food frequency questionnaire with 170 items. They calculated a Mediterranean diet score based on 9 energy-adjusted food groups and categorized the patients based on high, medium, or low adherence to the diet; they then looked for associations between diet score and progression-free survival (PFS).

Patients underwent confirmatory biopsies at the start of the study and had Gleason Grade Group (GG) 1 or 2 localized prostate cancer. They were monitored biennially, and PFS was defined as an increase in GG score. Cox proportional hazard models were used to adjust for other known risk factors in the analysis.

Men whose diets included more fruits, vegetables, legumes, grains, and fish were less likely to have their cancer advance to the point where active treatment was necessary. At a median follow-up of 36 months, the researchers found that for every 1-point increase in Mediterranean diet score, participants had a 12% lower risk of disease progression (HR per 1-point increase, 0.88; 95% CI, 0.77‐1.01).

In non-White men, the effect was even more pronounced (HR, 0.64; 95% CI, 0.45‐0.92; P = .07). Of the men in the overall cohort, 15% were had diabetes and 44% used statins. In men without diabetes, the HR was 0.82 (95% CI, 0.71‐0.96; P = .03).

“Men with prostate cancer are motivated to find a way to impact the advancement of their disease and improve their quality of life,” lead study author Justin Gregg, MD, assistant professor of urology at MD Anderson, said in a statement.⁵ “A Mediterranean diet is noninvasive, good for overall health, and, as shown by this study, has the potential to affect the progression of their cancer.”

The analysis was limited by a low number of events, with only 76 men seeing their cancer progress during the study. Disease risk was also low in most of the cohort, so larger and more diverse studies that include men with higher-risk disease are warranted to confirm the potential benefits of the Mediterranean diet, the authors wrote.

In cases where patients with low-risk disease and their physicians opt for active surveillance, exploring the potential of lifestyle changes to manage progression is of interest given the known quality-of-life adverse effects of active treatment for prostate cancer and cancer in general.

“The Mediterranean diet consistently has been linked to lower risk of cancer, cardiovascular disease, and mortality,” senior author Carrie Daniel-MacDougall, PhD, an associate professor of epidemiology at the University of Texas, said in the statement. “This study in men with early-stage prostate cancer gets us another step closer to providing evidence-based dietary recommendations to optimize outcomes in cancer patients, who, along with their families, have many questions in this area.”

References

1. Gregg JR, Zhang X, Chapin BF, et al. Adherence to the Mediterranean diet and grade group progression in localized prostate cancer: an active surveillance cohort. Cancer. Published online January 7, 2021. doi:10.1002/cncr.33182

2. Diet review: Mediterranean diet. Harvard T.H. Chan School of Public Health. Updated December 2018. Accessed January 22, 2021. https://www.hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/mediterranean-diet/

3. What is the Mediterranean diet? American Heart Association. Updated January 9, 2021. Accessed January 22, 2021. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/mediterranean-diet

4. Mentella MC, Scaldaferri F, Ricci C, Gasbarrini A, Miggiano GAD. Cancer and Mediterranean diet: a review. Nutrients. Published online September 2, 2019. doi:10.3390/nu11092059

5. Mediterranean diet may decrease risk of prostate cancer progression for men on active surveillance. News release. MD Anderson Cancer Center. January 7, 2021. Accessed January 22, 2021. https://www.mdanderson.org/newsroom/mediterranean-diet-may-decrease-risk-of-prostate-cancer-progression-for-men-on-active-surveillance.h00-159457689.html#.YAbliuVv8zE.mailto