@Dazzer, good points. And here's another interesting little-known factoid:

care.diabetesjournals.org/content/34/6/1249.abstract
Asian populations tend to develop diabetes at younger ages and lower BMI levels than Caucasians.

@Barbara, some of your points seem to be accurate. This article also suggests that MSG first creeped its way into low-protein dishes.

However, the way I interpret the following article is that MSG is chemically produced based on a naturally occurring flavor that was isolated (ie in seaweed). That neither makes it natural nor healthy. We don't really know how it was produced in the labs. And quite frankly, as a general rule of thumb, I believe that anything produced by men in white lab coats with murky motivations is Frankenfood to be avoided.

Ultimately, the only way to really know if MSG is harmful is to get a couple of rats and feed one a steady diet of MSG.

www.naturalnews.com/034031_MSG_health_effects.html
MSG was discovered in 1908 by Kikunae Ikeda, a Japanese scientist at the Tokyo Imperial University. He managed to isolate the flavour from a seaweed broth, and with the help of Ajinomoto Corporation of Japan, he patented it in 1909. It was then that it became available commercially for the first time. It is used in most restaurant cooking, especially in vegetarian dishes and low-protein foods.

And so Mr Ikeda found a way to extract MSG from seaweed.
That would appear to be a natural extract to me.

Dazzer, I will provide one last link here which suggests that the MSG found in certain foods and the MSG that is added to foods are different. But ultimately, there really isn't any way to prove it unless you strap on a white lab coat and get a couple of rats. The only proof that MSG added to foods is potentially harmful is:
1 - many people have adverse reactions to it
2 - the manufacturers seem to hide MSG on their labels. If that doesn't make you suspicious, well then knock yourself out.

www.blessedquietness.com/journal/theworld/msg.htm

What professor Ikeda discovered might have been quite benign, but once big food manufacturers got ahold of it, it has become a virtual poison in stimulant form.

Monosodium glutamate (MSG) is something you have to find on food labels because it is hidden by obscure substitute terms in grocery store products. Food producers know very well that, (a) MSG causes physical issues for many people, and (b) many of you know it. They INTENTIONALLY try to hide the fact that MSG is used in the food.

..............................

And this comment is quite interesting to me. In cultures that actually have good cuisine and cooks know how to use herbs and spices rather than splatter excessive la jiao on everything OR countries where every 2nd dinner isn't McDonald's or frozen crap, MSG isn't used. So even if it isn't harmful (which it is), you're only consuming it because a) you're not eating fresh food (UNHEALTHY!) or b) you don't know how to cook.

www.blessedquietness.com/journal/theworld/msg.htm

In India, south Asia, the Middle East, Africa, and Mexico where plenty of aromatic and hot spices are used, MSG is pointless and seldom used.

Comments like "Ultimately, the only way to really know if MSG is harmful is to get a couple of rats and feed one a steady diet of MSG." is crude science, and therefore unscientific.

Applying the same principal in an equally crude manner we can see that:
If you force feed a human too much salt, sickness and possibly death will follow.
If you deprive a human of salt, sickness and death will probably follow.

I was just trying to make the point that it's not really possible to know if the extraction is natural and harmless — because neither of us are scientists.

And yes, you're right. Quantities is another factor.

But if you want to talk about salt...there's a big difference between Iodized table salt and sea salt. As a general rule of thumb, the more processed something is the more harmful it is.

www.gokunming.com/[...]

There is NO MSG in the food!

I am going to be a lab rat when I go home to Georgia this summer. I am not eating fast foods and only eating home cooked meals. If I feel the difference then I will let you know. I think the msg has screwed up my thyroid glands and is wreaking havoc with my system. People say that Western food is bad for you but I don't think that the food I cook at home is bad and I will lay odds that it is healthier than Chinese food. Throwing down bowlfuls of rice is just empty calories and has no nutritional value. I think that there is a logical fallacy going on here called dicto simplicitor An argument in which a general rule is treated as universally true regardless of the circumstances: a sweeping generalization. Just because everyone in China believes that msg is good for you, regardless of the facts is illogical. Unfortunately, this is all too often the case in America also.

And also: "there's a big difference between Iodized table salt and sea salt. As a general rule of thumb, the more processed something is the more harmful it is."
Why? By just using logic and critical thinking wouldn't you say that Iodinized table salt is more benificial? (Apart from the fact that "Sea" NaCl is the same as the NaCl from salt mines)
1. Iodine is benificial for thyroid fuction
2. Wouldn't (unprocessed) sea salt is more potentially dangerous for your health because of pollution?

And also: "there's a big difference between Iodized table salt and sea salt. As a general rule of thumb, the more processed something is the more harmful it is."
Why? By just using logic and critical thinking wouldn't you say that Iodinized table salt is more benificial? (Apart from the fact that "Sea" NaCl is the same as the NaCl from salt mines)
1. Iodine is benificial for thyroid fuction
2. Wouldn't (unprocessed) sea salt be more potentially dangerous for your health because of pollution?