We present experimental results of chemical vapor deposition (CVD) diamond growth from ethanol vapor with the substitution of hydrogen by helium in concentrations varying from 0 to 95 vol.% He. Scanning electron microscopy (SEM) analysis revealed that the addition of helium to the gas phase influenced the growth rate and film structure. The deposition rate of diamond increases up to a helium concentration of 40 vol.% and then decreases. We attribute this behavior to an increase in the density of vacancies in the film or to a change in the reaction kinetics provoked by the chemical inertness of helium. Diamond films with well-defined crystalline facets and of good quality (measured by Raman spectroscopy) were obtained with the addition of up to 70 vol.% He. Use of helium also provokes an increase in film porosity, with the appearance of a strong room temperature photoluminescence with a Gaussian peak at approximately 635 nm. The intensity of the luminescence increases with the concentration of helium and is probably related to nanoporous defects introduced into the diamond structure.