• The authors evaluated the DASH diet and various levels of sodium intake on blood pressure (BP). They randomized 412 adults with pre- or stage 1 hypertension (not using antihypertensive medication) to either the DASH diet or a control diet; all patients were also randomly assigned three different sodium intake levels (50, 100, and 150 mmol/day for a 2100-kcal diet) over 4 weeks separated by breaks of 5 days. The low-sodium diet and the DASH diet alone each lowered BP from baseline. Compared with the high-sodium plus control diet, the combined low-sodium plus DASH diet lowered blood pressure by 5.3 mm Hg from baseline systolic BP <30 mm Hg, 7.5 mm Hg from baseline 130 to 139 mm Hg, 9.7 mm Hg from baseline 140 to 149 mm Hg, and 20.8 mm Hg from baseline ≥150 mm Hg (P for trend <.001).
• This study underscores the significant impact of healthy diet choices on blood pressure regardless of baseline blood pressure measurements. The authors emphasize that dietary intervention with low-sodium intake and the DASH diet may be particularly important and beneficial for individuals in the highest blood pressure strata (systolic BP ≥150 mm Hg).

Abstract

BACKGROUND

Both sodium reduction and the DASH (Dietary Approaches to Stop Hypertension) diet, a diet rich in fruits, vegetables, and low-fat dairy products, and reduced in saturated fat and cholesterol, lower blood pressure. The separate and combined effects of these dietary interventions by baseline blood pressure (BP) has not been reported.

OBJECTIVES

The authors compared the effects of low versus high sodium, DASH versus control, and both (low sodium-DASH vs. high sodium-control diets) on systolic BP (SBP) by baseline BP.

METHODS

In the DASH-Sodium (Dietary Patterns, Sodium Intake and Blood Pressure) trial, adults with pre- or stage 1 hypertension and not using antihypertensive medications, were randomized to either DASH or a control diet. On either diet, participants were fed each of 3 sodium levels (50, 100, and 150 mmol/day at 2,100 kcal) in random order over 4 weeks separated by 5-day breaks. Strata of baseline SBP were <130, 130 to 139, 140 to 149, and ≥150 mm Hg.

RESULTS

Of 412 participants, 57% were women, and 57% were black; mean age was 48 years, and mean SBP/diastolic BP was 135/86 mm Hg. In the context of the control diet, reducing sodium (from high to low) was associated with mean SBP differences of -3.20, -8.56, -8.99, and -7.04 mm Hg across the respective baseline SBP strata listed (p for trend = 0.004). In the context of high sodium, consuming the DASH compared with the control diet was associated with mean SBP differences of -4.5, -4.3, -4.7, and -10.6 mm Hg, respectively (p for trend = 0.66). The combined effects of the low sodium-DASH diet versus the high sodium-control diet on SBP were -5.3, -7.5, -9.7, and -20.8 mm Hg, respectively (p for trend < 0.001).

CONCLUSIONS

The combination of reduced sodium intake and the DASH diet lowered SBP throughout the range of pre- and stage 1 hypertension, with progressively greater reductions at higher levels of baseline SBP. SBP reductions in adults with the highest levels of SBP (≥150 mm Hg) were striking and reinforce the importance of both sodium reduction and the DASH diet in this high-risk group. Further research is needed to determine the effects of these interventions among adults with SBP ≥160 mm Hg.

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Journal Abstract