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Dietary Approaches to Stop Hypertension - DASH
Description:
Effects of varying levels of dietary sodium intake on blood pressure.
Hypothesis:
To study the effect of different levels of dietary sodium in conjunction with the DASH diet (rich in vegetables, fruits, and low-fat dairy products) in persons with and without hypertension.
Study Design
Patients Screened:
Patients Enrolled: 412
NYHA Class: Not reported
Mean Patient Age: Average 48 years
Female: 57%
Mean Ejection Fraction: Not evaluated
Patient Populations:
Age 22 years or older with systolic blood pressure 120-159 mm Hg and diastolic blood pressure 80-95 mm Hg and not taking any antihypertensive medication. 41% had hypertension defined as average systolic blood pressure of 140-159 mm Hg or an average diastolic blood pressure of 90-95 mm Hg during the three screening visits.
Exclusions:
Heart disease, renal insufficiency, poorly controlled hyperlipidemia, or diabetes mellitus, diabetes requiring insulin, special dietary requirements, intake of >14 alcoholic drinks per week, medications that affect blood pressure or nutrient metabolism
Primary Endpoints:
Systolic blood pressure at the end of each 30-day period of dietary intervention
Secondary Endpoints:
Diastolic blood pressure at the end of each 30-day period of dietary intervention
Drug/Procedures Used:
Randomized to a control diet that was low typical of intake in the United States or the DASH diet (rich in fruits, vegatables, and low-fat dairy products and with reduced saturated and total fat). Within the assigned, subjects ate food with high, intermediate, and low levels of sodium for 30 consecutive days each (in random order). Sodium targets were as follows: 150 mmol/day (high), 100 mmol/day (intermediate), and 50 mmol/day (low).
Principal Findings:
A reduction in sodium intake from high to intermediate decreased systolic blood pressure by 2.1 mm Hg (p < 0.001) during the control diet and by 1.3 mm Hg (p = 0.03) during the DASH diet. Reducing sodium from intermediate to low level resulted in further reductions of 4.6 mm Hg during the control diet (p < 0.001) and 1.7 mm Hg during the DASH diet (p < 0.01). These significant reductions occurred in both hypertensive and nonhypertensive subjects, blacks and those of other races, and men and women. Of note, the largest differential was seen between the control diet with high sodium intake and the DASH diet with low sodium intake (latter with systolic blood pressure that was 7.1 mm Hg lower in those without hypertension and 11.5 mm Hg in hypertensive subjects).
The original report from the DASH group found that a combination diet rich in fruits, vegetables, and low-fat dairy products and with reduced saturated fat and total fat resulted in a significant reduction in systolic and diastolic blood pressure compared to control diet (11.4 mm Hg and 5.5 mm Hg, respectively; both p < 0.001) [see N Engl J Med 1997;336:1117-24).
Interpretation:
The reduction of sodium intake to <100 mmol/day and the DASH diet both significantly lower blood pressure. The combination of the two was associated with the most substantial benefit.
References:
N Engl J Med 2001;344:3-10. Sodium study.
N Engl J Med 1997;336:1117-24. Diet report.
Keywords: Diet, Sodium-Restricted, Sodium, Dietary, Dairy Products, Hypertension, Systole
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