Dietary Approaches to Stop Hypertension (DASH) Diet and Blood Pressure Reduction in Adults with and without Hypertension: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of 30 randomized controlled trials
PubMed 32330233 · doi:10.1093/advances/nmaa041
What was done
Systematic review and meta-analysis of Medline and Cochrane Library databases including 30 randomized controlled trials with 5,545 hypertensive and nonhypertensive adult participants. The authors evaluated the effect of the DASH diet versus control diets on attained systolic blood pressure (SBP) and diastolic blood pressure (DBP) using fixed-effect and random-effects models, accompanied by subgroup and meta-regression analyses.
What was found
Compared with control diets, the DASH diet significantly reduced SBP (mean difference: -3.2 mm Hg; 95% CI: -4.2 to -2.3 mm Hg; P < 0.001) and DBP (mean difference: -2.5 mm Hg; 95% CI: -3.5 to -1.5 mm Hg; P < 0.001). Hypertension status did not significantly modify BP reductions. SBP reduction was greater in trials with daily sodium intake >2400 mg/d than in those with ≤2400 mg/d. Reductions in both SBP and DBP were greater in trials with a mean age <50 years compared to older cohorts. Quality of evidence was graded as moderate for both outcomes.
Why it matters
This review demonstrates that the DASH diet consistently lowers blood pressure regardless of baseline hypertension status, with enhanced reductions observed in younger adults and under conditions of higher daily sodium intake.
Limits
The abstract notes significant methodological and clinical differences across the included trials. Specific trial durations, adherence measures, long-term cardiovascular outcomes, and details regarding control diet composition are not reported in the abstract. Evidence certainty was rated as moderate rather than high.