Thank you. That 1999 study has, oddly, not been referenced by anyone other than groups that I mentioned earlier that link MSG to every conceivable ailment known to man. I can find no reviews, pro or con, by scientists, no mention of it at all.
That certainly doesn't mean that it has no merit.
"In summary, when resting humans ingest a large dose of MSG there is a rise in plasma glutamate that is large, peaks within 30–45 min, and is accompanied by a similar relative rise in plasma aspartate. This is accompanied and preceded by a rise in plasma insulin."
The above is its conclusion. How this translates to real-life situations for healthy people or those with diabetes I do not know.
BTW, I am not for or against MSG. I actually prefer to avoid excess sodium whenever possible.