Cardiovascular effects of black versus English walnut consumption

Abstract

English walnuts have been shown to decrease cardiovascular disease risk; however, black walnuts have not been studied for their cardioprotective effects. The purpose of this study was to determine the effects of English versus black walnut consumption on blood lipids, body weight, fatty acid composition of erythrocyte (red blood cell, RBC) membranes, and endothelial cell function. Consumption of 30 g of English walnuts per day for 30 days improved blood lipids; while the effects of black walnuts were dependent upon gender. Addition of either nut to the diet did not result in weight gain. The fatty acid composition of RBC membranes was favorably affected by walnut consumption. RBC polyunsaturated fatty acids increased after consumption of either type of nut, however, eicosapentanoic acid increased significantly more after English walnut consumption. Endothelial function was maintained after consumption of English walnuts with a high saturated fat meal; however, consumption of black walnuts with the same meal did not maintain endothelial function. Overall, these results support the recommendation that consumption of 1 oz of English walnuts per day may lower cardiovascular risk, but more research on black walnut consumption is necessary before an appropriate recommendation can be made.