Descriptive characteristics of the dietary patterns used in the Dietary Approaches to Stop Hypertension trial

The Dietary Approaches to Stop Hypertension trial was a randomized, multice nter, controlled feeding study to compare the effect on blood pressure of 3 dietary patterns: control, fruits and vegetables, and combination diets. T he patterns differed in selected nutrients hypothesized to alter blood pres sure. This article examines the food-group structure and nutrient compositi on of the study diets and reports participant nutrient consumption during i ntervention. Participants consumed the control dietary pattern during a 3-w eek run-in period. They were then randomized either to continue on the cont rol diet or to change to the fruits and vegetables or the combination diet for 8 weeks. Sodium intake and body weight were constant during the entire feeding period. Analysis of variance models compared the nutrient content o f the 3 diets. Targeting a few nutrients thought to influence blood pressur e resulted in diets that were profoundly different in their food-group and nutrient composition. The control and fruits and vegetables diets contained more oils, table fats, salad dressings, and red meats and were higher in s aturated fat, total fat, and cholesterol than was the combination diet. The fruits and vegetables and combination diets contained relatively more serv ings of fruits, juices, vegetables, and nuts/seeds, and were higher in magn esium, potassium, and fiber than was the control diet. Both the fruits and vegetables and combination diets were low in sweets and sugar-containing dr inks. The combination diet contained a greater variety of fruits, and its h igh calcium content was obtained by increasing low-fat dairy products. In a ddition, the distinct food grouping pattern across the 3 diets resulted in substantial differences in the levels of vitamins A, C, E, folate, B-6, and zinc.