Effects of diet and sodium intake on blood pressure: subgroup analysis of the DASH-sodium trial

Abstract

Background: Initial findings from the Dietary Approaches to Stop Hypertension (DASH)-Sodium Trial demonstrated that reduction of sodium intake in two different diets decreased blood pressure in participants with and without hypertension.

Objective: To determine effects on blood pressure of reduced sodium intake and the DASH diet in additional subgroups.

Design: Randomized feeding study.

Setting: Four clinical centers and a coordinating center.

Participants: 412 adults with untreated systolic blood pressure of 120 to 160 mm Hg and diastolic blood pressure of 80 to 95 mm Hg.

Intervention: Participants followed the DASH diet or a control (typical U.S.) diet for three consecutive 30-day feeding periods, during which sodium intake (50, 100, and 150 mmol/d at 2100 kcal) varied according to a randomly assigned sequence. Body weight was maintained.

Measurements: Systolic and diastolic blood pressure.

Results: In all subgroups, the DASH diet and reduced sodium intake were each associated with significant decreases in blood pressure; these two factors combined produced the greatest reductions. Among nonhypertensive participants who received the control diet, lower (vs. higher) sodium intake decreased blood pressure by 7.0/3.8 mm Hg in those older than 45 years of age (P < 0.001) and by 3.7/1.5 mm Hg in those 45 years of age or younger (P < 0.05).

Conclusion: The DASH diet plus reduced sodium intake is recommended to control blood pressure in diverse subgroups.