Earlier quoted context omitted.
I hadn't heard this claim about MSG before. I did a quick search on Google, but didn't find anything that looked remotely reputable. I did a quick search on Google Scholar, and everything seemed to be refuting the claim. Do you have any sources you can share?
Yeah, the grandparent is talking out of their rear-end. MSG is well researched and relatively safe. There have been numerous studies refuting the existence of "Chinese restaurant syndrome" and/or attributing the symptoms to allergy to MSG. "Syndrome" was originally a self-reported case study and none subsequent studies with n>10 have been able to replicate the case.
Hell, it wasn't even a paper. It was more along the lines of a letter to the editor, IIRC. But a mixture of sinophobia and alt-med woo spread it far and wide.