> Some people definitely have negative reactions it and other sources of free glutamates.

And some people have an allergy to water. I think GP meant "harmless" as referring to general population. There are always people who are allergic or otherwise harmed by things that are harmless to the 99.99% of humanity. Additional labeling might be justified if their number grows beyond a rounding error. And that still doesn't change the fact that unless you're the confirmed rare case for which X is harmful, you have no reason to fear it or to believe (and spread) misconceptions about it.

Funny that you quote from the excitotoxicity article but not the MSG article, which lists study after study proving that MSG in food is harmless. All reports of negative effects are anecdotal and unsubstantiated. This is for one of the most widely consumed chemicals in the world.

>study after study proving that MSG in food is harmless //

The side issue is objective truth here. So, you're telling me that no one has ever been harmed by consuming normal quantities of MSG? That's what "proven harmless" means.

It only requires one study to show some link between MSG and negative health effects to make it rational to seek that information, something like this http://www.ncbi.nlm.nih.gov/pubmed/27312658 maybe, suggesting neuronal destruction (using mice as a model). It's not proof.

For example, from the Wikipedia article on "Glutamate flavoring":

>"At a meeting of the Society for Neuroscience in 1990, the delegates had a split opinion on the issues related to neurotoxic effects from excitotoxic amino acids found in some additives such as monosodium glutamate."

If neuroscience experts don't have consensus, that would be a reason to avoid "additives such as MSG", no?

I still think that if we're going to do this democracy thing that people who want "no MSG" labels ['no free glutamate' would probably be more useful] should get them regardless of my view of their scientific basis.

Personally MSG doesn't really bother me, I don't like the "enhanced" taste with foods that are rich in it but a little seems fine. I do get headache and bloatedness after having the UK version of Chinese Restaurant food, seemingly more so than with other food types, but I'm pretty sure that's just over-eating [perhaps the enhanced flavour encourages it?].