WALNUTS for POWER: Polyphenols, Omega-3 Fatty Acids, Weight Loss, and EneRgy

This is a randomized control trial testing the effect of walnut supplementation on prostate cancer progression in 50 men with biopsy confirmed prostate cancer and planning to undergo RP. Patients consented to the study will be randomly assigned to either continue their usual diets (control arm) or to the walnut arm for 4-10 weeks depending on the window between their consent date and the date for RP.

Inclusion Criteria: * Pathologically confirmed prostate adenocarcinoma. * Diagnostic biopsy cores with ≥10 cores with each core examined separately to determine exact tumor location. * Biopsy grade group 2 or higher (Gleason ≥7). * Planning to undergo RP. * Willing to adhere to a usual diet with the possible addition of 2 oz of walnuts per day. * Reads, writes, and understands English. * Age 18 or older Exclusion Criteria: * Allergy to nuts. * History of receiving hormone therapy or antiandrogen therapy. * Use of 5-alpha reductase inhibitors in the past 6 months. * Prior prostate radiotherapy (external beam or brachytherapy) or prior prostate cryotherapy. * Currently enrolled in a modified diet/weight loss program and/or taking dietary supplements that contain omega-3s (e.g., fish oil). * Other active malignancy, excluding basal cell carcinoma or squamous cell carcinoma * Significant co-morbidities (e.g., cardiac, pulmonary, liver disease, alcohol/drug addiction, malabsorption syndromes), that in the opinion of the study physician make the patient ineligible. * Individuals with psychological/mental conditions which can affect the consent process and/or their adherence to the protocol.