Low-sodium DASH benefit increases with higher blood pressures

The low-sodium DASH diet lowered systolic BP mean of 20.8 mm Hg among patients with baseline systolic pressure of 150-159 mm Hg, and did so in just four weeks, according to a new analysis of the DASH-sodium trial.

The original 2001 study found that combining low sodium and the DASH [Dietary Approaches to Stop Hypertension] diet lowered blood pressure more than either alone, but the results were not broken out by hypertension severity.

It found that there were “progressively greater reduction at higher levels of baseline systolic BP (SBP). Among participants with baseline SBP at or above 150 mm Hg, “mean SBP reduction was striking.”

 The original trial randomized 208 subjects to DASH diet and 204 to a control diet similar to what most Americans eat. While on  their diets, the subject cycled through three sodium levels for 4 weeks each: 1.5 g/d, 2.4 g/d, and 3.3 g/d. Although deemed high sodium in the study, 3.3 g/d is typical for the American diet.

The new study analyzed outcome according to four baseline SBP categories: 120/129, 130/139, 140/149, and 150/159 mm Hg.

Among subjects on the control diet, reducing sodium from high to low intake reduced SBP 3.20, 8.56, 8.99 and 7.04 mm Hg across the four baseline SBP categories (P= .004). Among patients consuming high sodium, the DASH diet, compared with the control diet, reduced SBP 4.5, 4.3, 4.7, and 10.6 mm Hg, but the trend was not statistically significant.

The low sodium DASH diet, versus the high-sodium control diet reduced SBP 5.3, 7.5, 9.7, and 20.8 mm Hg in subjects with baseline SBP at or above 150 mm (P < .001).

“Our finding suggests that most adults with uncontrolled BP can experience substantial reduction in SBP from dietary changes alone,” the investigator said.

“To place our results in context, compared to placebo, angiotensin-converting enzymes inhibitors reduce SBP by 12 mm Hg, beta-blockers reduce SBP by 16 mm Hg.