Lycopene and lutein, another carotenoid found in tomatoes, act together on the endothelium by preventing leukocytes, or white blood cells causing inflammation, from adhering there.^8,9 In endothelial cells grown in the laboratory, these carotenoids significantly improved endothelial function, as shown by increased release of nitric oxide and decreased release of endothelin.⁹
 
Even better, lycopene and lutein decreased signaling of activated B cells (another type of white blood cell) by a protein known as inflammatory nuclear factor kappa-light-chain-enhancer (NF-κB). This reduced NF-κB signaling blocked production and release of molecules that encouraged leukocytes to stick to the endothelium, including tumor necrosis factor-alpha, inter-cellular adhesion molecule 1, and vascular cell adhesion molecule 1 (VCAM-1). Lycopene combined with lutein prevented leukocyte adhesion to the endothelium to a greater extent than either carotenoid acting alone.⁸