Diet may increase risk of death after prostate cancer diagnosis

BOSTON — After a prostate cancer diagnosis, eating a diet higher in red and processed meat, high-fat dairy foods, and refined grains—known as a Western diet—may lead to a significantly higher risk of both prostate cancer-related mortality and overall mortality compared with eating a diet rich in vegetables, fruits, fish, whole grains, and healthy oils, according to a new study from Harvard T.H. Chan School of Public Health.

The study, which appeared online June 1 in the journal Cancer Prevention Research, offers insight on how diet may help improve survivorship for the nearly three million men living with prostate cancer in the U.S.

“There is currently very little evidence to counsel men living with prostate cancer on how they can modify their lifestyle to improve survival. Our results suggest that a heart-healthy diet may benefit these men by specifically reducing their chances of dying of prostate cancer,” said Jorge Chavarro, assistant professor of nutrition and epidemiology at Harvard Chan School and senior author of the study.

Researchers examined health and diet data from 926 men participating in the Physicians’ Health Study I and II who were diagnosed with prostate cancer. They followed the men for an average of 14 years after their diagnosis, grouping them into quartiles according to whether they followed a Western dietary pattern or a “prudent” (higher consumption of vegetables, fruits, fish, legumes, and whole grains) dietary pattern.

They found that men who ate mostly a Western diet (those in the highest quartile of the Western dietary pattern) had two-and-a-half times higher risk of prostate cancer-related death—and a 67% increased risk of death from any cause—than those in the lowest quartile. Men who ate mostly a “prudent” diet had a 36% lower risk of death from all causes.

“These results are encouraging and add to the scant literature on this area, but it is important to keep in mind that all study participants are physicians and most are white. Therefore it is very important that our results are replicated in other studies with more diverse socioeconomic and racial/ethnic backgrounds,” said lead author Meng Yang, research fellow at Harvard Chan School.

Other Harvard Chan School authors of the study included Julie Batista, research associate, and Jing Ma, associate professor, both from the Department of Epidemiology; and Meir Stampfer, professor of epidemiology and nutrition.

Funding came from the U.S. Department of Defense (W81XWH-11-1-0529 to J.E. Chavarro), the National Institutes of Health (CA42182 to J. Ma; CA58684, CA90598, and CA141298 to M.J. Stampfer), and the Prostate Cancer Foundation (to S.A. Kenfield). This work was also made possible by grants supporting the PHS trial (CA97193 to Gaziano, CA40360 and HL34595 to Buring), the Boston Nutrition and Obesity Research Center (P30DK046200; PI: Fried), the Harvard TREC Center (1U54CA155626-01; PI: Hu), and the Dana-Farber/Harvard Cancer Center SPORE in Prostate Cancer (P50CA90381; PI: Kantoff).

“Dietary Patterns after Prostate Cancer Diagnosis in Relation to Disease-Specific and Total Mortality,” Meng Yang, Stacey A. Kenfield, Erin L. Van Blarigan, Julie L. Batista, Howard D. Sesso, Jing Ma, Meir J. Stampfer, and Jorge E. Chavarro, Cancer Prevention Research, online June 1, doi: 10.1158/1940-6207