MSG would come to America following WWII, along with many other Asian staples. One story goes that American cooks found that rations taken from the Japanese prisoners of war tasted far and away better than the American canned goods, and it was quickly found that this food essence was to blame. Over the next 60 odd years, MSG has taken hold in American food. Due to a branding problem, MSG has other names, such as Glutamate, Malodextrin, Yeast Extract, Gelatin, and Sodium Caseinate to name a few. Without these products, all of our canned goods, soups, etc. would be bland, lose flavor much quicker, and would have a huge impact on the food industry.
To give the greatest example of why humans love glutamate we can look at breast milk. Glutamate is far and away the most abundant amino acid in the milk, and is ten times higher a content level than cow's milk. Glutamate is one half of the flavor of breast milk, being sweet and savory so kids will eat it!
MSG has its negatives, namely, you want to eat more because it tastes so good! Take a look at the facts, google msg myth, figure out what you want to do, just don't be fooled by MSG free!