We constantly discuss diet and its implications on prostate cancer on both our on-line and face-to-face support groups. As an individual who does enjoy a steak I have made great strides in significantly restraining myself and greatly limit my consumption of red meat. However, I often wonder if all the talk about being a vegetarian was based on any actual evidence.

The typical western diet has been associated with prostate cancer incidence as well as risk of disease progression after treatment. A plant-based diets have been associated with decreased risks, but where is the evidence?

There was a recent pilot clinical trial extending over a brief period of six (6) months, which evaluated dietary change and stress reduction intervention for asymptomatic, hormonally untreated prostate cancer survivors who are experiencing a rising PSA level. Rising PSA scores, post surgery or radiation therapy are the first sign of recurrence of prostate cancer.

The trial was designed to investigate the level of intake of plant-based foods (vegetarian) and the relationship between intake and the change in the rate of PSA rise. Each survivor served as his own control in this pre-post trial design.

Survivors and their spouses were encouraged to adopt and maintain an only plant-based diet. The pre-study baseline rate of PSA rise (from the time of post-treatment recurrence to the start of the study) was established by review of the survivor’s medical records. Dietary assessments were performed and prostate-specific antigen (PSA) levels ascertained at baseline, prior to the start of intervention, and at 3 and 6 months. Changes in numbers of servings of plant-based food groups were calculated and compared with rates of PSA rise over the corresponding time intervals.

Median intake of whole grains increased from 1.7 servings/d at baseline to 6.9 and 5.0 servings/d at 3 and 6 months, respectively. Median intake of vegetables increased from 2.8 servings/d at baseline to 5.0 and 4.8 servings/d at 3 and 6 months, respectively.

The rate of PSA rise decreased when comparing the prestudy period (0.059) to the period from 0 to 3 months (-0.002, P < .01) and increased slightly, though not significantly, when comparing the period from 0 to 3 months to the period from 3 to 6 months (0.029, P = .4316).These results provide preliminary evidence that adoption of a plant-based diet is possible to achieve as well as to maintain for several months in patients with recurrent prostate cancer. Changes in the rate of rise in PSA, an indicator of disease progression, were successfully decreased as the intake of plant-based food groups increased.This study clearly raises the possibility that PSA velocity inversely tracked intake of these foods and suggests that adoption of a plant-based diet may have therapeutic potential in the management of prostate cancer.This study was conducted by:Jacquelyn Y. Nguyen, MD School of Medicine, University of California, San Diego, La Jolla, California. Jacqueline M. Major, MS Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, California. Cynthia J. Knott, MS, RD General Clinical Research Center, University of California, San Diego, La Jolla, California. Karen M. Freeman, MPH Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California. Tracy M. Downs, MD Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California. Gordon A. Saxe, MD, PhD Department of Family and Preventive Medicine, Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California,Joel T Nowak MA, MSW