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DASH Minus Sodium Equals Lower Blood Pressure

Nonpharmacological approaches to blood-pressure control tend not to get the attention they deserve. One effective strategy is the Dietary Approaches to Stop Hypertension (DASH) diet, which emphasizes fruits, vegetables, and low-fat dairy products and is low in saturated and total fat (see JWC Jun 1997, p. 47, accession number 970505002, and N Engl J Med 1997; 336:1117). Reducing the amount of sodium chloride in typical diets also can lower BP.

To determine whether lowering dietary-sodium intake enhances the DASH diet's BP benefit, researchers, in a crossover study, randomized 412 subjects to a typical U.S. diet (control) or to the DASH diet. Subjects ate their assigned diets at 3 sodium levels -- high (150 mmol/day, typical U.S. consumption), intermediate (100 mmol/day, current recommendation), and low (50 mmol/day) -- for 30 days each.

Compared with the control diet, the DASH diet resulted in lower mean systolic BP at each sodium-intake level, with the largest between-diets difference at the highest sodium level (difference, 5.9 mm Hg; 95 percent CI, 3.7-8.0). For both diets, reducing dietary-sodium intake lowered SBP progressively. Compared with the control diet at the highest sodium-intake level, the DASH diet at the lowest level yielded significant SBP reductions in subjects with and without hypertension (by 11.5 mm Hg and 7.1 mm Hg, respectively). Stratification by sex and race produced similar overall results.

Comment: The DASH diet can lower BP at various sodium-intake levels, and reducing these levels can lower BP in both typical and DASH diets. In this study, the combined effect of sodium-intake reduction and the DASH diet was greater than that of either alone. A combination dietary intervention can be a legitimate nonpharmacological option for BP control.

— HM Krumholz

Published in Journal Watch Cardiology March 2, 2001

Citation(s):

Sacks FM et al for the DASH-Sodium Collaborative Research Group. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. N Engl J Med 2001 Jan 4 344 3-10.

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