The objective of this ancillary study in DASH2 is to determine the impact of dietary patterns on rates of lipid peroxidation, serum antioxidant activity, and indicators of LDL-cholesterol oxidation, and to chart their time course.  The DASH2 trial provides the infrastructure for the proposed research.  DASH2 is a feeding study designed to assess the effects of 3 salt levels in 2 dietary patterns on blood pressure in 100 adults with systolic blood pressure 120-159 mmHg and diastolic blood pressure 80 to 95 mmHg.  For two weeks, participants are fed a control diet, low in fruits, vegetables, and dairy products, with fat and salt content typical of US consumption.  Participants are then randomized in a parallel arm design to (1) the control diet or (2) a "combination" diet rich in fruits, vegetables, and low-fat dairy products, and reduced in saturated and total fat.  Within each diet, participants receive three different sodium levels (50 mmol/d, 100 mmol/d, and 150 mmol/d), each for 30 days.  Study participants will be the 100 healthy volunteers to be enrolled in DASH2 at the Johns Hopkins General Clinical Research Center.  To date, we have collected blood and urine specimens from 35 randomized participants enrolled in the first of three feeding cohorts.  Sampling of blood and urine will take place, in addition to the baseline measurement (prior to randomization), at the end of each 30 day period.  The primary outcome measures, which are measures of oxidative damage, include urinary isoprostanes and malondialdehyde and serum antibodies to oxidized LDL.  The proposed study has the potential to enhance our basic understanding of the mechanisms by which diet affects these important intermediaries of cardiovascular disease.