A 1968 Letter Started a Health Scare That Was Never Backed by Evidence

On 4 April 1968 the New England Journal of Medicine published a one-paragraph letter from a Maryland physician, Robert Ho Man Kwok. He described a numbness in the back of the neck and palpitations after eating in Chinese-American restaurants and floated three possible culprits, of which monosodium glutamate was one. The editors gave the letter the title "Chinese Restaurant Syndrome." The phrase outlived everything else in the issue.

MSG is a sodium salt of glutamic acid, the same amino acid abundant in tomatoes, parmesan, and human breast milk. The Japanese chemist Kikunae Ikeda had isolated it from kombu seaweed in 1908 and named the taste umami. By 1968 it had been used in Japanese kitchens for sixty years and in American canned soups for several decades, with no reported syndrome.

What followed Kwok's letter was an unusual feedback loop. Newspapers picked up the story; readers reported their own symptoms; researchers, looking, found correlations in unblinded trials. Once double-blinding caught up — including a 1993 Australian study and a 1997 American review — the effect collapsed. People who reported MSG sensitivity could not, on average, distinguish MSG from a saline placebo when they did not know which they had received.

In 2018 the chef and author Eddie Huang and the food network Ajinomoto launched a campaign called RedefineCRS, arguing the term carried a cultural charge nothing in the chemistry justified. Merriam-Webster, in 2020, edited the dictionary entry. Chinese Restaurant Syndrome is no longer listed as a medical condition, only as a historical term.