In this work, we explore the evolution of the physicochemical properties of silicon carbide and titanium carbide nanoparticles in human reconstituted gastric fluid in the conditions of a normal digestion. The nanoparticles were pre-dispersed in water or in a pluronic F108 solution. Key parameters as the particle size distribution and the surface composition of the nanoparticles were monitored. The results show that the modifications produced during the simulated digestion are dispersion medium dependent. Carbon and nitrogen were found to be adsorbed on the surface of both nanoparticles in a dispersion medium dependent way. The reported results contribute to understand the biological impact of these nanoparticles in biofluids and biocompatible media.