The “Chinese Restaurant Syndrome”: History, Racism, Science, and a Joke

Kwok detailed his symptoms, including heart palpitations, weakness, and a feeling of numbness that started at the back of his neck and spread down his arms and back. Without any pretense of scientific rigor, he hypothesized that the causes might lie in salt, cooking wine, or perhaps monosodium glutamate, commonly known as MSG, used to flavor dishes. That letter, intended to spark a simple academic discussion, turned into a media and cultural avalanche, giving rise to what would be known for decades as the "Chinese Restaurant Syndrome."

From glutamate to syndrome

Nowadays, the concept of umami is not only accepted but probably also widely overused, so it's appropriate to frame the issue by recalling the history of glutamate, its purest source. Chemically speaking, MSG is the sodium salt of glutamic acid, one of nature's most abundant amino acids, naturally present in foods such as tomatoes, mushrooms, and aged cheeses. It's therefore not an element alien to Western gastronomy—far from it—and in Italian cuisine, it has always been expressed through slow cooking or the ubiquitous sprinkling of Grana Padano or Parmigiano Reggiano.

Its industrial history began in the early 1900s thanks to the Japanese chemist Kikunae Ikeda, who isolated it from kombu seaweed, the main ingredient of dashi broth, an indispensable cornerstone of Japanese cuisine, obtaining those small whitish crystals which he began mass producing by founding Ajinomoto, a name still synonymous with glutamate today.

With Japan's colonization of East Asia in the early 1900s, MSG spread widely, even gaining popularity among the Chinese population and leading to the emergence of competing local brands. It was through China that MSG entered American cuisine: after World War II, the American public's interest in Chinatowns and Chinese restaurants grew significantly, even prompting US food manufacturers to discreetly add the ingredient to canned soups, frozen meals, and military rations to enhance their flavor.

The cultural climate of the 1960s, however, would radically change public attitudes toward chemicals and food additives, and the publication of Dr. Kwok's letter in the New England Journal of Medicine in April 1968 set off a chain reaction. Within a month, the journal published ten additional responses from doctors who claimed to have experienced personal discomfort or that of their patients, listing symptoms as diverse as fainting, back spasms, sweating, dizziness, and flushed skin.

Reports were anecdotal and extremely inconsistent, with some doctors even claiming that the syndrome only occurred in certain geographic areas such as New York or California, while Hawaii and London were immune.

Despite the skepticism of the editors of the New England Journal of Medicine themselves, expressed in a tongue-in-cheek editorial, the press took the matter very seriously, fueling a collective panic that quickly demonized Asian cuisine. This represents only the latest wave of Sinophobia that has swept the country since the 19th century, when the popularity of Chinese cuisine among tourists in the first Chinatown, San Francisco, quickly turned to suspicion. Accusations of cooking rats, lizards, cats, and bats led to a racist movement that effectively halted Chinese immigration to the United States. These sentiments have not entirely vanished even in modern times; just think of the repugnant depictions of bats at wet markets during the Covid era.

Politically correct or not, the term “Chinese restaurant syndrome” entered common usage so forcefully that it was included in the prestigious American dictionary Merriam-Webster in 1993, a definition that was only modified in 2020 with the addition of the dated note and the warning that the term is considered misleading and potentially offensive.

The plot twist

The controversy took on the character of a true mystery in 2018, when a startling revelation emerged. Jennifer LeMesurier, a professor at Colgate University who had published a paper on the topic, received a message containing an incredible story: an orthopedic surgeon named Howard Steel claimed to be the letter's true author. Steel explained that he had made a ten-dollar bet with a colleague in 1968, claiming he could publish an article in the prestigious New England Journal of Medicine.

Inspired by a hearty lunch at a Chinese restaurant, he wrote the letter using the pseudonym Robert Ho Man Kwok and inventing an affiliation with the Silver Spring Biomedical Research Foundation. The name itself, reminiscent of the expression "a human crock of you-know-what," a broad, childish periphrasis of an insult, should have raised some eyebrows, but so be it. This confession, however, isn't enough to solve the case.

Yes, because a real Dr. Robert Ho Man Kwok really existed, he worked at that very foundation and his family has always confirmed that he was the one who wrote the original letter before he died in 2014. Whether it was an incredible coincidence or a prank by Steel, the mystery highlights the fragility on which the entire scandal was founded, and now seems destined to remain without a complete resolution.

The scientific evidence

In the years following the letter, public distrust was fueled by hasty and methodologically flawed scientific studies. Neurologist Herbert Schaumburg, who initially downplayed the effects of MSG, conducted experiments on very few volunteers, eventually claiming that the ingredient caused headaches, facial pressure, and burning. However, his experiments had serious flaws: the samples were very small, the tests were inadequately controlled, and the subjects took MSG on an empty stomach, a condition that would cause nausea and discomfort with any concentrated seasoning.

Shortly thereafter, a 1969 study conducted by psychiatrist John Olney raised further alarm. Olney injected massive doses of MSG directly under the skin of newborn mice, finding brain damage, obesity, and sterility. The study was harshly criticized because the doses used were equivalent to a massive human consumption in a single meal, and the subcutaneous administration route was certainly not representative: when normally ingested through food, almost all ingested glutamate is metabolized in the intestine and does not cross the blood-brain barrier.

It was only a matter of time, and since the 1970s, numerous rigorous scientific studies have debunked these theories. Major international organizations, including the JECFA committee managed by FAO and WHO in 1988, the European Commission in 1991, FASEB and the FDA in 1995, and the European Food Safety Authority (EFSA), have ruled out any scientifically proven link between MSG and the so-called Chinese restaurant syndrome. Today, in European products, glutamate is identified with codes ranging from E620 to E625, with E621 corresponding to monosodium glutamate.

While safe, experts still recommend moderation: the EFSA has established an acceptable daily intake of thirty milligrams per kilogram of body weight. For a seventy-kilogram adult, this corresponds to approximately two grams per day, an amount unlikely to be exceeded with a normal diet, unless one consumes enormous portions of foods naturally rich in glutamate, such as over one hundred and fifty grams of Parmigiano-Reggiano cheese at a single sitting. Furthermore, it is estimated that only a very small fraction of the population, less than one percent, may experience a true transient sensitivity to the ingredient.

Nowadays, any culinary content creator prides themselves on blessing every dish with a pinch of MSG, plucked from the unmistakable red and white Ajinomoto bag. But to achieve such ease, we've survived nearly a century of cultural prejudices and influences, during which—perhaps—a prankster has even complicated matters, turning a safe ingredient into a phantom menace, and demonstrating how urban legends can infiltrate even the scientific community.