Effects on blood pressure of reduced dietary sodium and the dietary approaches to stop hypertension (DASH) diet.

Background: The effect of dietary composition on blood pressure is a subjec t of public health importance. We studied the effect of different levels of dietary sodium, in conjunction with the Dietary Approaches to Stop Hyperte nsion (DASH) diet, which is rich in vegetables, fruits, and low-fat dairy p roducts, in persons with and in those without hypertension. Methods: A total of 412 participants were randomly assigned to eat either a control diet typical of intake in the United States or the DASH diet. With in the assigned diet, participants ate foods with high, intermediate, and l ow levels of sodium for 30 consecutive days each, in random order. Results: Reducing the sodium intake from the high to the intermediate level reduced the systolic blood pressure by 2.1 mm Hg (P<0.001) during the cont rol diet and by 1.3 mm Hg (P = 0.03) during the DASH diet. Reducing the sod ium intake from the intermediate to the low level caused additional reducti ons of 4.6 mm Hg during the control diet (P<0.001) and 1.7 mm Hg during the DASH diet (P<0.01). The effects of sodium were observed in participants wi th and in those without hypertension, blacks and those of other races, and women and men. The DASH diet was associated with a significantly lower syst olic blood pressure at each sodium level; and the difference was greater wi th high sodium levels than with low ones. As compared with the control diet with a high sodium level, the DASH diet with a low sodium level led to a m ean systolic blood pressure that was 7.1 mm Hg lower in participants withou t hypertension, and 11.5 mm Hg lower in participants with hypertension. Conclusions: The reduction of sodium intake to levels below the current rec ommendation of 100 mmol per day and the DASH diet both lower blood pressure substantially, with greater effects in combination than singly. Long-term health benefits will depend on the ability of people to make long-lasting d ietary changes and the increased availability of lower-sodium foods. (N Eng l J Med 2001;344:3-10.) Copyright (C) 2001 Massachusetts Medical Society.