Walnuts (Juglans regia) have been traditionally consumed for their overall health benefits, but in recent decades, their role in supporting heart health has been supported by scientific research. Numerous studies have investigated the effects of walnut consumption on cardiovascular health, particularly focusing on cholesterol levels, endothelial function, and inflammation.

Walnuts are rich in polyunsaturated fatty acids, including alpha-linolenic acid (ALA), an omega-3 fatty acid, as well as antioxidants such as polyphenols and vitamin E. Randomized controlled trials and meta-analyses have demonstrated that including walnuts in the diet can lower total cholesterol and low-density lipoprotein (LDL) cholesterol, both of which are risk factors for heart disease. For example, a 2019 meta-analysis in the American Journal of Clinical Nutrition concluded that walnut-enriched diets significantly reduce LDL cholesterol and total cholesterol compared to control diets.

There is also evidence that walnuts may improve endothelial function and reduce markers of inflammation, further supporting their cardiovascular benefits. However, most evidence relates to risk factor modification rather than direct treatment of "heart weakness" (a non-specific or traditional term). Therefore, while walnuts have scientifically validated benefits for heart health, they should be considered as part of a heart-healthy diet rather than a treatment for established heart disease or "heart weakness."