Richman, E.L., Carroll, P.R. and Chan, J.M. (2012) Vegetable and Fruit Intake after Diagnosis and Risk of Prostate Cancer Progression. International Journal of Cancer, 131, 201-210.
ABSTRACT: Recommendations for prostate cancer treatment include weight loss, but the most efficacious diet has not been determined. Men on active surveillance or with untreated biochemical relapse consumed both the diet recommended by the Prostate Cancer Foundation (PCF) and a plant-based that included three tablespoons of extra virgin olive oil per day for 8 weeks of weight loss and improvement in some laboratory biomarkers with random assignment to the diet order. They then selected one of the diets for six months of follow-up. Thirty men started the protocol and 18 completed the 44 week study. Mean age: 66.6 ± 5.9 years; baseline body mass index: 30.9 ± 2.7 kg/m2. Weight loss was comparable between the diets after 8 weeks (PCF: 2.5% ± 3.1% v olive oil: 2.8% ± 3.7%; p = 0.86), but the diet that included olive oil resulted in lower insulin (PCF: 13.7 ± 7.0 mU/L v olive oil: 11.5 ± 4.4 mU/L; p = 0.02), glucose (PCF: 104.9 ± 9.9 mg/dl v 99.1 ± 9.6 mg/dl; p = 0.01), and HOMA-IR (PCF: 3.6 ± 2.1 v olive oil: 2.9 ± 1.2; p = 0.02). Thirteen of the 18 men choose the olive oil diet for six months of follow-up and weight loss and lab improvements were maintained. This pilot study indicates that both the PCF diet and the plant-based diet that included extra virgin olive oil can produce similar weight loss short-term. However, a plant-based diet that includes extra virgin olive may be more acceptable for long-term use, and produce better glycemic control.