Study: Mediterranean Diet May Decrease Risk of Prostate Cancer Progression for Men on Active Surveillance

Researchers from the University of Texas MD Anderson Cancer Center found that men with localized prostate cancer who reported a baseline dietary pattern that more closely follows the key principles of a Mediterranean-style diet fared better over the course of their disease.

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

Men with a diet that contained more fruits, vegetables, legumes, cereals, and fish had a reduced risk of their prostate cancer growing or advancing to a point where many would consider active treatment after adjusting for factors known to increase the risk of cancer progression, such as age, prostate-specific antigen (PSA) levels, and tumor volume. Additionally, the researchers examined the effect of diabetes and statin use and found a similar risk reduction in these patient groups.

The study also found that the effect of a Mediterranean diet was more pronounced in African American participants and others who self-identified as non-white. These findings were significant, as the rate of prostate cancer diagnosis is more than 50% higher in African American men, who also have a higher risk of prostate cancer death and disease progression, according to the study authors.

“The Mediterranean diet consistently has been linked to lower risk of cancer, cardiovascular disease and mortality,” said senior study author Carrie Daniel-MacDougall, PhD, in a press release. “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.”

The study followed 410 men on an active surveillance protocol with Gleason grade group 1 or 2 localized prostate cancer. All participants underwent a confirmatory biopsy at the beginning of the study and were evaluated every 6 months through clinical exam and laboratory studies of serum antigen PSA and testosterone.

The participants were 82.9% Caucasian, 8.1% Black, and 9% other or unknown. The median age was 64 years, 15% of the men were diabetic, and 44% were using statins.

The men completed a 170-item baseline food frequency questionnaire, and Mediterranean diet score was calculated for each participant across 9 energy-adjusted food groups. The participants were then divided into 3 groups of high, medium, and low adherence to the diet, according to the study authors.

The researchers saw a significant association between high baseline diet score and lower risk of cancer grade progression after adjustments for age and clinical characteristics were taken into consideration. For every 1-point increase in the Mediterranean diet score, researchers observed a less than 10% lower risk of progression. After a median follow-up of 36 months, 76 men saw their cancer progress.

The study had limitations, including the low number of events in these men with mostly low risk disease monitored at MD Anderson. The study authors noted that further research is needed to see whether the same effects are seen for larger and more diverse patient groups and men with higher-risk prostate cancer.

“Our findings suggest that consistently following a diet rich in plant foods, fish and a healthy balance of monounsaturated fats may be beneficial for men diagnosed with early-stage prostate cancer,” Gregg said in a press release. “We are hopeful that these results, paired with additional research and future validation, will encourage patients to adapt a healthy lifestyle.”

REFERENCE

Mediterranean diet may decrease risk of prostate cancer progression for men on active surveillance. MD Anderson Cancer Center. https://www.mdanderson.org/newsroom/mediterranean-diet-may-decrease-risk-of-prostate-cancer-progression-for-men-on-active-surveillance.h00-159457689.html#:~:text=In%20a%20study%20to%20examine,the%20key%20principles%20of%20a. Published January 7, 2021. Accessed January 8, 2021.