Plant-Based Diets and Cardiovascular Disease: A Systematic Review of Prospective Studies

Abstract

Introduction: Plant-based diets are increasingly popular, but their definition varies from vegan to flexitarian. The association with cardiovascular disease (CVD) incidence across different dietary patterns is not fully quantified.
Methods: Systematic search of Medline and Scopus for prospective cohort studies (≥5 years follow-up) with validated food frequency questionnaires. Included healthy adults at baseline. Exposure: plant-based diet index (PDI) measuring adherence to plant foods (fruits, vegetables, whole grains, nuts). Healthy vs. unhealthy plant foods were distinguished. Outcome: incident CVD (MI, stroke, HF).
Results: 15 cohorts (n=1.2 million) with 85,000 CVD events. Highest vs. lowest quintile of overall PDI associated with 16% lower CVD risk (RR 0.84, 0.79–0.89). Healthy plant-based diet (hPDI emphasizing whole grains, fruits, vegetables) reduced risk by 25% (RR 0.75, 0.70–0.81). Unhealthy plant-based diet (refined grains, sugary drinks) increased risk by 12% (RR 1.12, 1.04–1.20). The benefit was partly mediated by lower BMI and blood pressure (37% of effect). No significant difference between vegetarians and vegans.
Discussion: Quality of plant foods is critical; not all plant-based diets are equally heart-healthy. Limitations include residual confounding by other lifestyle factors (physical activity, smoking) and self-reported diet. Most cohorts were from North America and Europe.
Conclusions: A healthy plant-based diet rich in minimally processed plant foods is associated with substantially lower CVD risk. Public health messages should emphasize plant food quality, not just avoidance of animal products.