Dietary Approaches to Stop Hypertension (DASH) for the primary and secondary prevention of cardiovascular diseases

The effect of the DASH diet on major cardiovascular outcomes - including myocardial infarction, stroke, cardiovascular mortality, and all-cause mortality - remains inconclusive due to a lack of robust long-term evidence. Additionally, no trials have assessed its impact on heart failure or the need for revascularisation procedures, such as coronary, carotid, or peripheral interventions. While the DASH diet may reduce blood pressure, total cholesterol, and triglyceride levels while increasing high-density lipoprotein (HDL) cholesterol compared to no intervention or usual care, it appears to have little to no effect on low-density lipoprotein (LDL) cholesterol. Evidence comparing the DASH diet to a minimal intervention or alternative dietary approaches remains limited. Although the DASH diet has minimal reported adverse effects, the absence of long-term safety data prevents definitive conclusions on its use in individuals with or without cardiovascular disease. The certainty of evidence is low to very low, primarily due to design limitations such as high risk of bias, small sample sizes, and short follow-up periods in the included trials. Most studies focused on cardiovascular risk factors rather than long-term clinical outcomes, and all eligible trials assessed primary prevention, with no data on secondary prevention. Given these uncertainties, well-designed, long-term randomised controlled trials are needed to evaluate the DASH diet's impact on major cardiovascular events, its effectiveness in secondary prevention, and its long-term safety.