Validation of diet composition for the Dietary Approaches to Stop Hypertension trial

The Dietary Approaches to Stop Hypertension trial involved 4 clinical sites at which 459 participants (in 5 cohorts) were fed 3 dietary patterns over 11 weeks per cohort. The 3 patterns were a control diet, a fruits and veget ables diet, arid a combination diet. Before the intervention, key nutrient levels in each diet were validated at 2 energy levels (2,100 and 3,100 kcal ) by chemical analysis of the prepared menus. During intervention, diets we re sampled across all cohorts, sites, and energy levels, and 7-day menu cyc le composites were assayed. In general, sodium, potassium, calcium, and mag nesium in the validated menus for each diet/energy level met lie nutrient t argets, though moderate variability was evident among individual menus, par ticularly for potassium, calcium, and magnesium. However, as intended, ther e was clear separation and no overlap in mineral levels in individual menus of diets that were designed to differ. During intervention, macronutrient contents met nutrient goals. Sodium, potassium, calcium, and magnesium in t he diets generally met target levels, though potassium in the fruits and ve getables diet was 11% to 23% below target. There were no consistent differe nces in nutrient levels between sites. The mean nutrient levels in the vali dated menus and diets sampled during intervention were in excellent agreeme nt with each other, though sodium was somewhat higher (similar to 6%) in th e diets from intervention vs validation. These results indicate the success of the quality control measures implemented and suggested consistent overa ll diet composition throughout the 28 months during which the study was con ducted.