Effects of different dietary interventions on blood pressure: Systematic review and meta-analysis of randomized controlled trials

Previous studies have shown beneficial effects of individual dietary approaches for blood pressure (BP) control, but their relative effectiveness is not well established. We performed a systematic review of published dietary pattern interventions and estimated the aggregate BP effects through meta-analysis. PubMed, EMBASE, and Web of Science databases were searched to identify studies published between January 1, 1990 and March 1, 2015. Studies meeting specific inclusion and exclusion criteria were selected. Data were pooled using random effects meta-analysis models. Twenty-four trials with 23 858 total participants were included. The overall pooled net effect of dietary intervention on systolic BP and diastolic BP was -3.07 mm Hg (95% confidence interval, -3.85 to -2.30) and -1.81 mm Hg (95% confidence interval, -2.24 to -1.38), respectively. The Dietary Approaches to Stop Hypertension diet had the largest net effect (systolic BP, -7.62 mm Hg [95% confidence interval, -9.95 to -5.29] and diastolic BP, -4.22 mm Hg [95% confidence interval, -5.87 to -2.57]). Low-sodium; low-sodium, high-potassium; low-sodium, low-calorie; and low-calorie diets also led to significant systolic and diastolic BP reductions, whereas Mediterranean diet participants experienced a significant incremental reduction in diastolic but not systolic BP. Subgroup analysis also showed important variations in effectiveness based on duration, size, and participant demographics. In conclusion, dietary modifications are associated with clinically meaningful, though variable, reductions in BP. Some diets are more effective than others and under different circumstances, which has important implications from both clinical and public health perspectives.