Long ago, in a land called the 1990s, our food fears were very different than they are now. Sure, we've been worried about MSG on some level for ages. But back in the '90's, it was all about avoiding fat. The low-carb craze had barely started and we still thought fat was the devil, and Snackwell’s cookies of sadness—fat-free but with plenty of sugar (because we weren't freaking out about sugar yet, not really)—still roamed the munchies aisle. “Non-GMO” labels hadn’t been graffitied on every box of granola. And Kale was the name of a guy in my brother’s class, not the launch of a million health trends. Nowadays, we’re awash in food-specific chemophobia, largely thanks to the popularity of “clean eating,” which drives us towards GMO-, chemical-, and so-called-toxin-free foods and food products, even after information becomes available that the things we thought were dangerous are actually perfectly safe.
One food fear has persisted since the 1960s: the mortal danger caused by monosodium glutamate, also known as MSG. I remember my father requesting “no MSG” when we went out to Chinese restaurants. I was young and I don’t remember much other than hearing that it was bad for you and that Chinese food never quite tasted as good when we went out with my father.
Thanks to the internet, we have the ability to both debunk old wives’ tales and make up new ones. But no matter how many efforts are made by science writers, there is always someone who says MSG gives them headaches. Or it gives them intestinal problems. Or the MSG ate their homework. (It’s worth noting that some people may have sensitivity to MSG when ingesting it in large amounts, but the chances of something like this happening is so small that MSG sensitivity isn’t widespread—more on that below.) Despite the fact that the FDA first recognized MSG as safe in 1959—1959!—56 years later in 2015, $ 9.2 billion worth of food products were labeled as being MSG-free. The history of our love/fear relationship with MSG is wrought with bad science and more than a dash of xenophobia. If you want that wonderful umami flavor in your food, let’s calm your food fears and take a look at the science of the salt.
What exactly is MSG?
Let’s parse this piece by piece. Glutamate is a form of glutamic acid, an amino acid that’s naturally occurring in many common foods, like tomatoes and cheeses. In 1908, a Japanese chemist named Ikeda Kikunae noticed the distinct flavor—one not covered by the classical “four flavor grouping” of sweet, sour, salty, and bitter—in a seaweed broth called konbu. Though other chefs had identified the unique flavor before, Kikunae was the first one to chemically isolate the glutamate from the seaweed. In one of few cases when licking the specimen is advisable, Kikunae determined that it was responsible for the flavor, which he called “umami,” derived from the word Japanese word umai, roughly translating to “deliciousness.” That’s right—the person who discovered umami is the same person who created MSG. Glutamate is an ionized form of glutamic acid, and Kukunae combined it with sodium to form the crystallized product that was shelf stable, dissolved easily into food, and gave the world ready access to that wonderful umami flavor.
How did MSG fear start?
If you know someone who claims to have a negative reaction to MSG, you can thank the New England Journal of Medicine for publishing a letter from Dr. Robert Ho Man Kwok in 1968 under the title “Chinese Restaurant Syndrome” (CRS). Dr. Kwok said that he never experienced any negative symptoms after eating food in his native China, but here in the U.S., Chinese food caused him to experience an array of symptoms, including “numbness at the back of the neck, gradually radiating to both arms and the back, and general weakness and palpitation.” The NEJM was then inundated with personal accounts of similar symptoms. It’s important to note that Dr. Kwok merely suggested MSG as one of many possible causes of his symptoms, as opposed to laying the blame squarely on it, but the notion stuck. As we’ve seen time and again, when unproven hypotheses and anecdotal evidence enter the vernacular and the collective consciousness, they’re hard to vanquish.
Despite the absence of high-quality data on “Chinese Restaurant Syndrome,” MSG quickly absorbed the blame for it, and the fear of it hasn’t diminished over the years.
Why are people so convinced that we all should avoid MSG?
MSG was introduced to the United States in the 1930s; to this day, MSG is found in packaged soups, salad dressings, crackers, and chips around the world. But even though Americans were consuming MSG in the products they bought from supermarkets, the ingredient has come to be thought of as unique to Chinese restaurants. Why did we only expect it from Chinese food and not from other glutamate-containing foods? Why don’t we hear about headaches from, for example, Campbell’s soups, which, until recently, had MSG added to it? I've never heard of a complaint about mushrooms or pasta with parmesan cheese. Some scholars believe that Americans’ negative perceptions of China and Chinese people are at least partially responsible for MSG’s demonization. It’s a fairly common conclusion that our fears of MSG, specifically in Chinese food, were partially the result of xenophobia.
But fear of chemicals in foods played a role, too. A few things were happening around the time that CRS was proposed that raised public awareness about food additives. In 1958, a controversial law that required the FDA to ban cancer-causing food additives went into effect. In 1962, Rachel Carson’s book Silent Spring helped launched the environmental movement. It also ignited a new awareness (and somewhere between a healthy and overblown fear) of the effects of chemicals in our everyday lives.
Is there any evidence that MSG is bad for you?
No. A 2009 paper in Social History of Medicine illustrates how early studies of MSG that were either flawed in execution or interpretation set the stage for widespread fear about the chemical. For example, in a 1968 study co-authored by a neurologist and a pharmacologist concluded that MSG, “in the amounts used in the preparation of widely consumed foods,” caused Chinese Restaurant Syndrome. But this study did not address why food products already in common use had not been flagged as products that could cause these same effects. In 1969, a psychiatrist who had studied MSG told the New York Times that his own findings on MSG raised question about its safety for pregnant women. That, on its own, sounds alarming. But his study examined the effects of large doses of MSG on pregnant mice (finding that it caused brain lesions, stunted skeletal development, obesity, and sterility). Other influential studies that demonized MSG came under scrutiny and criticism because their findings were not reproducible or were designed in ways that their results couldn’t be generalized to the way human beings actually consume MSG.
We now know that the data says, over and over again, that MSG is safe (and the FDA categorizes it as “generally safe to eat”). A meta analysis published in the Journal of the American Academy of Nurse Practitioners in 2006 showed that there had been no consistent ability to show any causal relationship between MSG and “Chinese Restaurant Syndrome.” In 2000, researchers set out to analyze the responses to MSG in people who had reported symptoms from ingesting it, and found that they could not reproduce these effects. Finally, a 2016 review concluded that a causal relationship between MSG and CRS has not been proven.
According to the FDA, some people may experience mild symptoms when they eat three or more grams of MSG on an empty stomach. Keep in mind, though, that a typical serving of food has less than 0.5 g of MSG, so consuming three grams without food is unlikely, which is why this doesn’t give a lot of useful information about the actual safety of ingesting MSG. (Hey, if you ate three grams of salt on an empty stomach, that could give you some symptoms, too.) And if you’re worried about MSG versus the glutamate naturally occurring in foods, you probably don’t have to be. The FDA’s website says that the “glutamate in MSG is chemically indistinguishable from glutamate present in food proteins. Our bodies ultimately metabolize both sources of glutamate in the same way. An average adult consumes approximately 13 grams of glutamate each day from the protein in food, while intake of added MSG is estimated at around 0.55 grams per day.”
All that said, just because a scientific association hasn’t been found between the MSG you consumed and your headache, it doesn’t mean the headache isn’t happening. Perhaps it’s the “nocebo effect,” which happens when the suggestion of a symptom causes that very symptom to occur. Or maybe you are someone who happens to have a sensitivity to MSG. It’s just that this is not a food sensitivity that has been shown, by science, to exist in a widespread way.
So what can you do to keep yourself safe and still occasionally enjoy more than a lettuce leaf, extra sadness? There’s always going to be a new article about which chemicals are killing you. Or what acidity level your body is supposed to be at to kill cancer. Or which food is the new superfood that’s vibrationally in tune with your yoni jade egg (I’m not here to judge you). But unless there’s some science behind it, try re-examining your old food fears. I’m not telling you that you have to eat MSG if you don’t like the flavor, but at least consider the evidence. The scientific method is a safer bet than anecdotes, and there’s a good reason MSG flavor is synonymous with “delicious.”
Yvette d'Entremont holds a B.S. in chemistry, B.A. in theatre, and a master's degree in forensic science with a concentration in biological criminalistics. She worked for eight years as an analytical chemist before her blog focused on debunking bad science, scibabe.com, turned into a full-time job in science communications. Follow her on Twitter and Facebook.