We investigate the electron-energy-loss spectrum of one-dimensional undoped CuO3 chains within an extended multiband Hubbard model and an extended one-band Hubbard model, using the standard Lanczos algorithm. Short-range intersite Coulomb interactions are explicitly included in these models, and long-range interactions are treated in the random-phase approximation. The results for the multiband model with standard parameter values agree very well with experimental spectra of Sr2CuO3. In particular, the width of the main structure is correctly reproduced for all values of momentum transfer. We find no evidence for enhanced intersite interactions in Sr2CuO3.