A Japanese chemist named Kikunae Ikeda invented MSG, which looks like tiny crystals of brown or white sand, in the early 1900s. He then founded the Ajinomoto corporation to mass-produce the seasoning.
After some initial struggles to find customers—restaurants and soy-sauce brewers shunned it as untraditional—Ajinomoto found success targeting homemakers. To make its product fashionable, the company packaged MSG in elegant glass bottles, like perfume, and pushed them especially hard in finishing schools for the daughters of Japanese elites. The Japanese government also helped. A seasoning invented by a chemist had an air of technological sophistication that appealed to officials intent on modernizing the country through science and technology. As a result, MSG seasoning exploded in popularity in Japan.
As Japan colonized much of East Asia in the early 1900s, MSG followed the sword. Ajinomoto’s products became associated with Japanese imperialism, especially in China. Nevertheless, many Chinese people liked MSG, which made food taste more savory. Knockoff brands arose to compete with Ajinomoto and soon began dominating the market.
It’s through China that MSG first entered American cuisine. After the attack on Pearl Harbor, nationalist backlash against the Japanese was swift and brutal. President Roosevelt incarcerated more than 100,000 innocent Japanese Americans in internment camps, and the public developed a newfound sympathy for China, which had suffered under Japanese occupation for decades. Many Americans without Chinese heritage began exploring Chinese culture, including visiting Chinatowns and eating at Chinese restaurants. As a result, by the late 1940s MSG-rich Chinese food was growing popular stateside. American food manufacturers began quietly adding it to canned soups and TV dinners to add some zip, and the military put MSG in soldiers’ MRE rations. Everyone seemed happy.
Then came the 1960s. Books such as Silent Spring, while focused on pesticides, suddenly made people wary of “chemicals,” including dyes, artificial sweeteners, and other food additives. In a time of mistrust and suspicion, a “foreign” chemical like MSG became an easy target.
The MSG panic began in April 1968, when Kwok wrote the letter to the New England Journal of Medicine (NEJM) outlining his symptoms (racing heart, weakness, numbness), and fingering three possible culprits—salt, cooking wine, or perhaps MSG.
A month later, the NEJM printed 10 responses from other doctors. Like Kwok, the doctors reported discomfort after eating Chinese food, either in themselves or in friends or patients. (Unlike Kwok, none distinguished between Northern and Southern Chinese cuisines; they lumped all Chinese food together.)
The symptoms catalogued in the letters included fainting, back spasms, sweating, dizziness, flushed skin, and a numb jaw. Puzzlingly, though, no two letter writers listed the same symptoms. And the possible links between them was anyone’s guess: they appeared all over the body and came on at widely varying times after eating.