Whole Food Plant-based Diet to Improve Outcomes in Prostate Cancer

The purpose of this research is to determine if consuming a whole food plant-based diet for six months impacts outcomes in men with prostate cancer that have a rising prostate-specific antigen (PSA) level. The main questions it aims to answer are: Does a whole-food plant-based impact PSA? Does a whole food plant-based diet impact risk factors associated with treatment for prostate cancer including LDL cholesterol, hemoglobin A1C, C-reactive protein? Participants will be asked to attend twelve two-hour plant-based cooking and nutrition classes throughout a six-month period, consume a mostly whole food plant-based diet, provide blood samples, and complete three-day food journals to assess nutrient intake.

Ten men with histologically or cytologically confirmed adenocarcinoma of the prostate will be recruited from local urologists and oncologists. Eligible participants will be asymptomatic with a rising PSA on at least two tests no more than 6 months apart. Participants will come from one of four categories: 1) early stage, not on therapy; 2) non-metastatic prostate cancer on therapy; 3) metastatic, not on therapy; 4) metastatic, on antiandrogen (i.e. leuprolide) therapy that is no longer effective. Participants will attend 12 two-hour group educational sessions at Pacific Cancer Care over the course of 24 weeks to encourage increased consumption of whole plant foods including fruits, vegetables, legumes, nuts, seeds, and decreased consumption of processed and animal foods including refined carbohydrates, meat, seafood, eggs, and dairy. Strict elimination of animal foods will not be required allowing dietary flexibility. Educational sessions will consist of a 1-hour presentation on various nutrition topics with an emphasis on the benefits of whole plant foods, a 30-minute cooking demonstration of a whole food plant-based meal and taste test, and a 30-minute discussion. Participants will be encouraged to bring one support person, preferably someone they share meals with such as a spouse, to the sessions. A booklet summarizing the information presented in the educational sessions, including whole food plant-based recipes, will be provided to participants and their support person. Participants will be provided with a "take-home" ingredient that was used to prepare the meal in class and organic produce boxes from weeks 1 through 9 and $20 gift cards for weeks 10 through 24. The primary outcome will be change in PSA, which will be measured at baseline, 12 weeks, and 24 weeks. Secondary outcome measures will be assessed at baseline and 24 weeks including changes in nutrient intake as assessed by 3-day food journals, LDL cholesterol, hemoglobin A1C, and high sensitivity C-reactive protein. Insulin-like growth factor-1 and insulin-like growth factor binding protein-3 will also be measured.