Mechanism of the Blood Pressure Lowering Effect of the DASH Dietary Pattern

Randomized, controlled feeding trials have established the BP lowering effects of the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, which emphasizes fruits, vegetables and low fat dairy and is low in saturated and total fat. The DASH studies were designed to establish efficacy, not to determine mechanism of action. Other studies suggest that the DASH diet may have effects on the renin-angiotensin-aldosterone system (RAAS). These effects have not been directly evaluated, nor have other potential mechanisms of action such as effects on adrenergic tone, vascular function and inflammation. The BP-lowering effect of the DASH dietary pattern was maximal after two weeks of controlled feeding, and was comparable in magnitude to antihypertensive medication among participants with stage 1 hypertension. Understanding the possible mechanism(s) by which the DASH diet lowers BP will potentially enhance the value of this intervention by elucidating the conditions under which it will be most effective, identifying target populations, examining its impact on vascular health beyond BP, and enhancing our understanding of the interactions among diet, BP and vascular function. In addition, results of this study may help to identify additional therapeutic targets. Therefore, the overall goal of the proposed study is to determine the mechanism(s) by which the DASH diet lowers BP. Our unifying hypothesis is that DASH diet lowers BP through effects on vascular function and sodium excretion, mediated through the effects on RAAS.