Walnuts (Juglans regia) have been extensively studied for their potential benefits in cardiovascular health. Multiple clinical trials and meta-analyses have demonstrated that regular walnut consumption can improve several cardiovascular risk factors. Walnuts are rich in polyunsaturated fatty acids, especially alpha-linolenic acid (ALA), a plant-based omega-3 fatty acid, as well as antioxidants and phytosterols. These components are believed to contribute to their cardioprotective effects.

Scientific evidence indicates that walnuts can modestly lower total cholesterol and low-density lipoprotein (LDL) cholesterol levels, while potentially improving endothelial function and reducing inflammation. For example, a 2019 systematic review and meta-analysis published in the American Journal of Clinical Nutrition found that walnut-enriched diets reduced total and LDL cholesterol compared with control diets. The PREDIMED trial, a large randomized controlled trial, also indicated that a Mediterranean diet supplemented with nuts, including walnuts, reduced the incidence of major cardiovascular events.

While walnuts are not a replacement for medical therapy, the evidence supports their inclusion as part of a heart-healthy diet. Overall, the use of walnuts for cardiovascular disease prevention and support is justified by scientific validation, with a substantial body of moderate- to high-quality human evidence supporting their benefit.