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

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.

Inclusion criteria

• Males 45-99 years of age
• Histologically or cytologically confirmed adenocarcinoma of the prostate
• Increasing PSA on at least 2 sequential tests not more than 6 months apart.
• Eastern Cooperative Oncology Group Performance Status Scale of 0 to 2
• Adequate organ and marrow function, based upon meeting all of the following laboratory criteria:

• White blood cell count ≥ 2500/mm3 (≥ 2.5 GI/L)
• Platelets ≥ 50,000/mm3 (≥ 100 GI/L) without transfusion
• Hemoglobin ≥ 9 g/dL (≥ 90 g/L)
• Alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin ≤ 2x upper limit of normal (or for subjects with Gilbert's syndrome direct bilirubin WNL) Serum albumin ≥ 2.8 g/dl
• Willingness and ability to comply with all study-related procedures
• Capable of understanding and complying with the protocol requirements and must have signed the informed consent document

Exclusion criteria

• Nut or legume allergy
• Currently consuming a vegetarian or vegan diet
• Concurrent participation in other nutrition or weight loss programs
• Expected changes in exercise patterns during the study period
• Active prostatitis
• Insulin-dependent or requiring diabetes mellitus
• Expected changes in chronic medications, including statins or oral diabetes medication during the study period (including a change in medication dosage)
• Expected radiation, chemotherapy, bone resorptive agents or anti-androgen within 2 months of beginning the diet intervention
• Known history of electrolyte imbalance or micronutrient deficiency, e.g., magnesium, cobalamin
• Ongoing use of warfarin anticoagulants
• Diagnosed, active inflammatory bowel disease
• Alcohol and/or drug abuse
• Psychiatric illnesses or social situations that would limit compliance with study requirements including the inability or lack of equipment to perform basic cooking tasks