Put another way, “DASH focuses on consuming all the food groups,” says Abbie Gellman, a registered dietitian and author of The Mediterranean DASH Diet Cookbook.
How DASH lowers blood pressure—and why it works so quickly
DASH’s reputation is most closely tied to its effects on hypertension. For decades, clinical trials have shown that the diet can lower systolic blood pressure within weeks, with reductions comparable to first-line blood pressure medications in some individuals.
A key mechanism behind this benefit is sodium reduction. On average, Americans consume about 3,300 milligrams of salt daily, but DASH recommends limiting intake to about 1,500 milligrams per day—well below the federal recommendation of less than 2,300 milligrams daily. “Lower sodium intake reduces plasma volume, which decreases pressure on arterial walls,” Goodson explains.
The diet also targets nutrients that influence blood vessel function and fluid stability by “creating a better balance of minerals in the body,” says Kate Zeratsky, a registered dietitian-nutritionist at Mayo Clinic.
It does so by emphasizing potassium-, magnesium-, and calcium-rich foods—nutrients that help relax blood vessel walls, improve arterial elasticity, and counteract the blood pressure-raising effects of sodium.
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Equally important are the foods DASH crowds out. By reducing added sugars, refined carbohydrates, and saturated fat, the diet helps lower inflammation and improves endothelial function, insulin sensitivity, and blood vessel responsiveness, which, in turn, supports better circulation, reduces vascular stiffness, and improves overall cardiovascular function.
Put another way, Messer explains that DASH works on both sides of the equation: It cuts back on processed foods—the largest sources of hidden sodium—while also increasing the minerals that support heart health and help the kidneys excrete excess sodium.
Beyond blood pressure: Why DASH supports whole-body health
While DASH was designed to specifically address hypertension, “its robust history of study gives us confidence in recommending it not only for blood pressure but also for many broader health benefits,” Zeratsky says.
Large observational studies and controlled trials link the DASH diet to improved insulin sensitivity, lower cholesterol, weight loss, and reduced risk of cardiovascular disease and type 2 diabetes.
One reason for such benefits is that “plant-forward diets like the DASH diet are a major contributor to daily fiber intake,” says Gellman.