Background: The Dietary Approaches to Stop Hypertension (DASH) diet, which emphasizes fruits, vegetables, and low fat dairy products, significantly lowers blood pressure (BP). We conducted a clinical trial to assess the BP response to the DASH diet with an antihypertensive medication, losartan, in participants with essential hypertension.
Methods: A total of 55 hypertensive participants were randomly assigned to 8 weeks of controlled feeding with either a control diet or the DASH diet. Within each diet arm, participants received losartan 50 mg daily or placebo for 4 weeks each, in double blind, randomized, cross-over fashion. Twenty-four-hour ambulatory BP (ABP) was measured at the end of a 2-week run-in period (baseline) and after each 4-week intervention period.
Results: There was no significant change in ABP during the placebo period on the control diet (n = 28) (-2.3 +/- 1.5/-1.6 +/- 1.0 mm Hg), but there was a significant reduction in systolic ABP (-5.3 +/- 1.5 mm Hg, P <.05) and no change in DBP (-2.5 +/- 1.0 mm Hg) on the DASH diet (n = 27). Losartan significantly reduced ABP on the control diet (-6.7 +/- 1.5/-3.7 +/- 1.0 mm Hg, P <.05) and to a greater extent on the DASH diet (-11.7 +/- 1.5/-6.9 +/- 1.0 mm Hg, P <.05 versus basal and control diet) particularly in African Americans. On the DASH diet, DeltaSBP on losartan was inversely related to basal plasma renin activity (n = -0.53, P =.004).
Conclusions: The DASH diet enhances the ABP response to losartan in essential hypertension. This effect is particularly marked in African Americans.