The effects of dietary patterns on plasma renin activity: results from the Dietary Approaches to Stop Hypertension trial

A diet rich in fruits, vegetables and low-fat dairy products, and reduced in saturated fat, total fat and cholesterol (the 'DASH' diet) significantly lowers blood pressure (BP). Previous studies have documented that certain therapies that lower BP increase plasma renin activity (PRA). Using data from the Dietary Approaches to Stop Hypertension (DASH) trial, we assessed the effects of dietary patterns on PRA and determined the relationship of change in PRA with change in BP on each diet. After eating a control diet for 3 weeks, participants were then randomized to receive for 8 weeks: the control diet, a diet rich in fruits and vegetables (F/V), or the DASH diet. Baseline and follow-up levels of PRA were available in 381 participants. Compared with the control diet, the DASH diet increased PRA by 0.37 ng ml(-1) h(-1) (P = 0.01). In multivariable linear regression analyses, there was an inverse association of PRA change with systolic BP change on the control diet (slope = -0.35, P = 0.001), but PRA did not differ by BP change on the F/V diet (slope = -0.002, P = 0.98) or DASH diet (slope = -0.08, P = 0.32). These data suggest that a blunted counter-regulatory response of the renin-angiotensin system is associated with the BP-lowering effect of the F/V and DASH diets. Journal of Human Hypertension (2012) 26, 664-669; doi: 10.1038/jhh.2011.87; published online 3 November 2011