Effect of dietary patterns on ambulatory blood pressure - Results from theDietary Approaches to Stop Hypertension (DASH) Trial

We measured ambulatory blood pressure (ABP) in 354 participants in the Diet ary Approaches to Stop Hypertension (DASH) Trial to determine the effect of dietary treatment on ABP (24-hour, day and night) and to assess participan ts' acceptance of and compliance with the ABP monitoring (ABPM) technique, After a 3-week run-in period on a control "typical" American diet, subjects (diastolic blood pressure [BP], 80 to 95 mm Hg; systolic BP, <160 mm Hg; m ean age, 45 years) were randomly assigned to 1 of 3 diets for an 8-week int ervention period: a continuation of the control diet; a diet rich in fruits and vegetables; and a "combination" diet: that emphasized fruits, vegetabl es, and low-fat dairy products. We measured ABP at the end of the run-in an d intervention periods. Both the fruit/vegetable and combination diets lowe red 24-hour ABP significantly compared with the control diet (P<0.0001 for systolic and diastolic pressures on both diets: control diet, -0.2/+0.1 mm Hg; fruit/vegetable diet, -3.2/-1.9 mm Hg; combination diet, -4.6/-2.6 mm H g). The combination diet lowered pressure during both day and night. Hypert ensive subjects had a significantly greater response than normotensives to the combination diet (24-hour ABP, -10.1/-5.5 versus -2.3/-1.6 mm Hg, respe ctively). After correction for the control diet responses, the magnitude of BP lowering was not significantly different whether measured by ABPM or ra ndom-zero sphygmomanometry. Participant acceptance of ABPM was excellent: o nly 1 participant refused to wear the ABP monitor, and 7 subjects (2%) prov ided incomplete recordings. These results demonstrate that the DASH combina tion diet provides significant round-the-clock reduction in BP, especially in hypertensive participants:.