Debunking MSG & “Chinese Restaurant Syndrome”

Salt is used to season virtually everything – from the simple scrambled eggs made five minutes before your first Zoom meeting, to an entire pot roast that took the whole day to prepare. In addition to amplifying salty flavors in food, table salt, or sodium chloride, brings out sweetness while simultaneously suppressing bitterness, making food tastier. Because humans like eating tasty things, salt has become intertwined with cooking in general; a meal devoid of salt is a bad meal almost by default. You might think then that if we discovered another form of salt, one that could enhance different flavor profiles within food and thus expand our perceivable spectrum of tastiness, we would welcome it with open arms, clear a spot next to our stoves for it, name our first-born children after it, etc. Well I have good news! That salt exists – it brings out umami or savory flavors in food, like those found in tomatoes, mushrooms, and asparagus. Enhancing a food’s savory flavors doesn’t necessarily mean making it more salty; you probably wouldn’t call mushrooms salty, for example, but you would definitely call them savory. This umami salt was first extracted from seaweed in the early 1900s by a Japanese chemist, who aptly referred to it as “essence of taste.” Chemically speaking, it’s also known as monosodium glutamate, or MSG.

My guess is that you’ve heard of MSG before and that you may have some not exactly stellar opinions of it. Especially in the US, MSG has gotten a bad rap. There are anecdotes that MSG causes headaches, allergic reactions, and tingling limbs – and there are even reports from the 1960s in revered peer edited journals, such as The New England Journal of Medicine (NEJM) and Science, that warn of its toxic properties. These specific reports catalyzed the negative outlook that much of the American public has towards MSG. And with good reason – these journals are some of the highest impact journals that publish today. Yet, closer inspection of these articles reveal that they are actually scientifically unreliable, and that the bad rap associated with MSG is more likely a result of one man’s assumptions and possible xenophobia.

The letter that NEJM published in the 1960s was written by a doctor named Robert Ho Man Kwok, who wrote that he experienced symptoms of an allergic reaction every time he ate at a Chinese restaurant. While in his letter he doesn’t identify a specific ingredient responsible for his symptoms, he doesn’t hesitate to give his set of symptoms a name – “Chinese-Restaurant Syndrome” (CRS). Less than a year later, Science published a research study by John W. Olney, who injected MSG into laboratory mice and found that the compound caused several neurological issues, including neural decay of developing mouse brains and stunted skeletal growth. Taken together, these two publications implicated MSG as the culprit for CRS, giving MSG a reputation that it has not been able to escape to this day.

But there is a crucial problem with Olney’s study – he chose to inject MSG into mice, even though humans only ingest MSG by eating it. When we eat MSG, it gets exposed to enzymes in our digestive system that can break it down into harmless metabolites. Additionally, Olney injected his mice with a huge excess of MSG, proportionally hundreds of times more than a human would ever eat at once, and anything consumed in excess can be dangerous. Ultimately, the study failed to recreate how humans realistically consume MSG, making its findings unreliable. 

Interestingly, just one year after Olney’s paper was published, Nature published a study by P.L. Morselli and S. Garattini investigating the effects of MSG in humans when eaten. The study took a small set of participants, split them into two groups, and fed them beef broth – one set of participants had broth with MSG while the other set did not. The participants were then asked to report how they felt over the next three hours. Notably, they did not observe any differences in subjective symptoms between the two groups, and they also noted that no participants experienced symptoms related to CRS. Over the next several decades, this type of study would be repeated more quantitatively and on a larger scale, all to the general conclusion that there is no reliable scientific evidence suggesting that MSG is responsible for symptoms associated with CRS. But despite all these studies, a simple google search of MSG still returns a slew of warnings and cautionary tales.

There may of course be people that truly are sensitive to MSG, like how some people are intolerant of dairy. But MSG is not a widespread toxin or poison, and you might be surprised to learn how many of your favorite snacks already have it (Doritos, anyone?). And regarding CRS, let’s just drop that name already! Maybe you do feel some type of way after eating Chinese food, but people who have gluten sensitivities don’t warn about “bread syndrome” after eating a sandwich. Don’t blame the bread! Don’t blame the Chinese food! Personally, I find both MSG and Chinese food delightful, and would encourage you to try seasoning a home-cooked meal with a little pinch of MSG to give it that extra oomph. After all, don’t you wonder what an expanded spectrum of tastiness actually tastes like?

Peer edited by Brittany Shepherd