In systems composed of water and hydrocarbons, Van der Waals interactions are dominated by the nonretarded, classical (Keesom) part of the Lifshitz interaction; the interaction is screened by salt and extends over mesoscopic distances of the order of the size of the (micellar) constituents of complex fluids. We show that these interactions are included intrinsically in a recently introduced local Monte Carlo algorithm for simulating electrostatic interactions between charges in the presence of nonhomogeneous dielectric media.