Great question. As of a few years ago, the research indicated that unless you were eating huge amounts of MSG, it should not change your blood glutamate levels, and is even less likely to change brain levels of glutamate. https://pubmed.ncbi.nlm.nih.gov/30508818/#:~:text=Monosodium%20Glutamate%20in%20the%20Diet,Concentrations%20or%20Disrupt%20Brain%20Functions