Effectiveness of Mediterranean diet for the primary prevention of cardiovascular diseases: A systematic review and meta-analysis featured in the Italian National Guidelines “La Dieta Mediterranea”

Background Cardiovascular diseases (CVDs) are among the leading causes of premature mortality in Europe, with unhealthy diets a major contributing factor. The Mediterranean diet (MD), characterized by high intake of plant-based foods and healthy fats, has been associated with reduced cardiovascular risk. This systematic review and meta-analysis aimed to assess the effectiveness of MD in the primary prevention of CVDs. Methods This review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 and Meta-analysis of Observational Studies in Epidemiology guidelines. A comprehensive search of PubMed/MEDLINE, Scopus, Embase, and Cochrane Library was performed up to February 28, 2024. Study quality was assessed using the Newcastle–Ottawa Scale, and the certainty of evidence was evaluated with the NUTRIGRADE approach. Pooled effect sizes were computed using a random-effects model and expressed as risk ratios, hazard ratios (HR), or odds ratios, as appropriate. Results A total of 87 studies, encompassing over 1.4 million participants, were included. Higher adherence to the MD was consistently associated with a reduced risk of peripheral artery disease (HR—from 0.34 to 0.54), coronary heart disease (HR: 0.95), atrial fibrillation (HR: 0.65), cerebrovascular disease (HR: 0.97), hypertension (HR: 0.97), and CVDs mortality (HR: 0.97). Even a one-point increase in MD adherence score conferred a statistically significant benefit. The strongest evidence emerged from high-quality RCTs, notably the PREDIMED study. Conclusions The MD is an effective strategy for the primary prevention of CVDs. These findings suggest the importance of adherence to MD and support incorporating MD-based recommendations in national dietary guidelines and public health initiatives.