Participants completed a minimum week-long washout period without consumption of tomato products prior to randomization to one of four dietary interventions. Men were randomized to one of the following dietary interventions: a controlled low lycopene diet (≤ 5 mg/d from foods), daily Prego® spaghetti sauce, daily V8® vegetable juice, or daily Campbell's® Tomato Soup. Each of the tomato products provided between 25 and 35 mg lycopene per day. In order to provide this dietary intervention in typical serving sizes in the context of a usual diet but devoid of other tomato sources, participants kept daily logs documenting compliance with the intervention product and a tomato-restricted diet from enrollment to the day of surgery (\~3 weeks). Study participants were asked to complete an abbreviated dietary history questionnaire (to establish typical consumption patterns of various tomato products) and two separate 3-day diet food records, once during the washout and once during the intervention period. Blood and 24-hour urine samples were obtained at two time points, after the one-week washout phase and at the end of the dietary intervention period. Fresh prostate samples were obtained at time of surgery.
