The talk of glutamic acid made me wonder if fish sauce is related to MSG. Gemini confirms MSG is just salt and glutamic acid, which is to say fish sauce is naturally derived MSG.

Fun story:

I was riding a motorcycle across Vietnam a few years ago. Made some friends on an excursion, and we all went to dinner together. The restaurant was a little outdoor kitchen and some picnic benches in front of an apartment building.

When we arrived, the mom was taking orders. She spoke enough English to serve travelers. One of my new friends ordered a sandwich, and fell in love with the sauce it came with. I offered to find out what was in it, but the mom had gone upstairs. Dad didn't speak a word of English.

We managed to ask him about the sauce, and he beckoned us to follow him behind the counter. He pointed at a mason jar of white powder: sugar. He pointed at another: salt. He pointed at a third: salt … wait, we already did salt…

It was MSG. This chef in a rural mountain town had just a handful of ingredients in his kitchen, and one was MSG.

As a 90s kid who grew up hearing of MSG is the same breath as processed foods, sulfites, and other health boogymen, it was wild to encounter it as just another ingredient in someone's pantry.