Impact of the Level of Adherence to the DASH Diet on Blood Pressure: A Systematic Review and Meta-Analysis

Amidst the increasing prevalence of hypertension, a healthy diet is a widely recognized modifiable risk factor in the prevention and management of this condition. To date, several studies have supported the beneficial effects of the Dietary Approaches to Stop Hypertension (DASH) diet, which consists of high daily intakes of fruits and vegetables (8-10 servings), and dairy products (2-3 servings, mostly low-fat) on blood pressure.

To this effect, a systematic review and meta-analysis synthesized the findings of 37 studies including over 293,000 adult participants from 15 different countries. In their quantitative analysis of 29 observational and interventional studies, the authors assessed the relationship between blood pressure parameters (systolic [SBP] and diastolic blood pressure [DBP]) and the level of adherence to the DASH diet, which was measured with existing DASH assessment tools. Analyses accounted for confounding variables (ex. food literacy, socioeconomic status, medical history, readiness for change, etc.) as well as common risk factors for hypertension (ex. age, smoking, etc.).

Overall, results revealed more favourable SBP and DBP values in those with high adherence to the DASH, when compared to those with low adherence in the main analysis. Beneficial associations between DASH adherence and blood pressure were also observed in a subgroup analysis of 16 studies conducted in participants who were not receiving antihypertensive pharmacotherapy.  

This systematic review and meta-analysis is among the first to consolidate evidence on the relationship between adherence to the DASH and blood pressure and reinforces the DASH as an integral part of the lifestyle management of hypertension. Furthermore, the authors also note in addition to a reduced risk of hypertension, the DASH diet may also be beneficial for reducing the risk of stroke, coronary heart disease, and type 2 diabetes.