MSG and “Chinese Restaurant Syndrome”: Real effect or racial prejudice?

MSG and “Chinese Restaurant Syndrome”: Real effect or racial prejudice?

By Jason Lo Hog Tian

Monosodium glutamate (MSG) is a powerful flavour enhancer that has been a staple in cooking for decades. However, if you have spent any amount of time in a Western country, you are probably aware of the negative reputation of MSG. In fact, many of you may actively avoid MSG after hearing about the negative effects of using the mysterious powder to transform any food from dull to delicious. A deeper dive into the history of MSG reveals that fears are based less in science and more around racialized attitudes that developed after mass immigration to America.

MSG is the salt of glutamic acid, an abundant and naturally occurring amino acid, and was first discovered in 1908 by chemist Ikeda Kikunae in Japan. MSG was isolated from sea kelp-which gives it the signature umami flavour, meaning “tasty” in Japanese. The product was initially brought to market in Japan under the brand name Ajinomoto, meaning “essence of taste”. It quickly spread around the world, ending up in restaurants throughout the United States by the 1930’s and becoming an integral food staple in the American war effort.1 However, following its initial rise to popularity, the flavour enhancer would soon come under fire due to a phenomenon that remains prevalent to this day – consumer fear.

In the 1960’s, consumer trust in industry products collapsed and fear around the dangers of chemicals such as pesticides, additives, and sweeteners rose to an all-time high. MSG would soon be added to the quickly growing “do not use” list after a letter published in the New England Journal of Medicine in 1968 by Dr. Robert Ho Man Kwok describing what he called “Chinese Restaurant Syndrome” (CRS) after eating at a Chinese restaurant. Symptoms included numbness in the neck and arms, weakness, and heart palpitations.2 The letter resonated with readers  and soon there were countless responses flooding in from individuals claiming to have experienced similar symptoms following the consumption of Chinese food. Subsequent scientific studies appeared shortly after this initial finding that “confirmed” the role of MSG in the development of CRS.3 One such study appeared in 1977 from Harvard Medical School which claimed that 25% of people experienced CRS. By this time, the evidence against MSG was damning and public opinion of the flavour enhancer had turned sour.4

Vintage MSG ad from Ajinomoto kabushiki gaisha shashi [Company History of Ajinomoto Incorporated] (Ajinomoto kabushiki gaisha, 1971), volume 1

Despite the growing evidence of the negative impacts of MSG, many scientists remained skeptical and upon further investigation, the seemingly ironclad evidence started to unravel. The first study to demonstrate the effect of MSG using a variety of delivery methods was not blinded and had a sample size of only six.5 The study conducted at Harvard included leading questions such as “Do you think you get Chinese restaurant syndrome?” and listed the potential symptoms, creating recall bias.4 Another study conducted on individuals claiming MSG sensitivity found that when given more than 2.5 grams of MSG, participants began to experience headache and flushing.6 However, this is a rather large dose – equivalent to about 200 grams of Parmesan cheese – and was given on an empty stomach, making the scenario rather unrealistic. So, while there are many studies condemning the use of MSG, there are clearly some holes in the narrative and more rigorous evaluation was required.

In 2000, a combined team of Boston University, Harvard University, Northwestern University, and UCLA scientists conducted a double-blind, placebo-controlled study aimed at understanding the true nature of MSG and its side effects. The study recruited individuals with a self-proclaimed MSG hypersensitivity and administered either MSG or a placebo dissolved in a drink. Subjects were instructed to fast for 8 hours and were given a breakfast after consuming the drink.7 Throughout all research sites, there were no reproducible effects of MSG exposure – individuals reporting MSG sensitivity could not tell when they had MSG or the placebo.

While it is plausible that MSG could cause adverse reactions at high doses and with certain delivery methods, there is no evidence to date supporting the idea of MSG causing CRS, especially when used under reasonably normal conditions. The U.S. Food and Drug Administration (FDA) has classified MSG as generally recognized as safe (GRAS) since 1958, and despite the overwhelming negative public opinion about the compound, the FDA has never changed its position.8 However, while the scientific community and governmental organizations have come to a consensus that MSG is not harmful, the general public has been slower to change their opinion. Figure 1 shows the results of a survey conducted in 2018 by the International Food Information Council (IFIC), an industry-funded non-profit organization. The survey shows that over 40% of U.S. consumers still actively avoid MSG, demonstrating that MSG is still a greatly feared product, right behind artificial additives, preservatives, sodium, and sugars.9 With science defending the effects of MSG, why is the general public maintaining such a strong stance?

The nocebo effect – negative expectations causing more negative effect than would otherwise occur – is likely the main culprit for individuals claiming MSG hypersensitivity. The same survey from the IFIC shows that consumers no longer trust traditional authorities regarding nutrition and safety, choosing to rely more on personal experience, anecdotes from friends or family, and health blogs.9 Food companies now proudly place “No MSG Added” stickers on their products to hold on to their share of the market which further exacerbates the stigma against MSG. Understanding the reason behind the unmoving public opinion may require a deep dive into the origins of CRS and where the MSG aversion came from – stigmatizing attitudes towards Asian immigrants.

If it was the MSG causing CRS, why were symptoms appearing only after eating Chinese food? MSG has been used for decades in Asia and even in Western cuisine following World War II, yet CRS reports remained isolated to  Chinese food specifically. The initial popularization of CRS came at a time of high Chinese immigration rates in the U.S., and Americans were concerned about “exotic, bizarre, and excessive practices” associated with Chinese culture.10 When news broke about a sickness coming from Chinese restaurants, people did not question its plausibility  and their deep seeded suspicions about Chinese practices were confirmed. Scientists and laypeople alike were blinded by the narrative of a decidedly Chinese illness caused by MSG and failed to explore why other MSG products didn’t to show the same effects. While racist laws barring Chinese immigration to America were removed over 50 years ago, remnants of old stigmatizing attitudes may persist and will likely take more time to completely disappear.

If any of you have actively avoided MSG, you may feel like you have been “fooled” by this misinformation. However, negative attitudes towards MSG have been so pervasive in culture and media that it is hard not to internalize some of those beliefs. Overall, this is a lesson to remain ever skeptical. The claims around CRS seemed credible – studies “confirming” the syndrome were conducted at prestigious institutions and published in influential journals, media sources relentlessly reinforced the idea, and most of the public were adamant in their belief. Like with any form of misinformation, a large part of changing public opinion is raising awareness around the knowledge gap and educating the public about best practices. We, as citizens of the world, must always question where ideas come from and the rationality behind those claims, even if it seems like the entire world is behind it. While CRS may have its roots in racial prejudice, the fear of MSG grew into a health-related consumer fear until it permeated Western culture – something we still feel today over 50 years later.

IMS writer Jason Lo Hog Tian is a 2nd year MSc doctoral stream student at IMS investigating the barriers preventing people living with HIV from seeking treatment under the supervision of Dr. Sean Rourke. He is committed to developing his scientific communication skills through writing for the magazine. [twitter] @JasonLoTweets

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