 The intervention, a daily supplementation with 3g supplement of fish oil monoglycerides rich in EPA, vs. placebo capsules containing high oleic sunflower oil, will start six weeks before the prostatectomy and will continue for one year after surgery. The potential confounding variables will be measured before the start of the intervention: age, anthropometric parameters, stage and clinical and pathological tumor grade Gleason score, pre-operative level of prostate specific antigen and diet. 