Unlike juice, which has sort of a mixed reputation even among contemporary nutritionists and doctors, MSG has been consistently demonized. Most people can’t tell you why, they just know that it’s bad. If pressed, they might tell you that it’s "unnatural," that food manufacturers put it in processed foods to con people into eating "junk," that it’s basically salt (which I’ll address in a future post in this series), or that it gives some people headaches. Or they might just gesture to the fact that it’s common knowledge that MSG is basically some kind of poison—after all, why would Chinese restaurants be so eager to reassure you that they don’t use it if it were completely benign?
A recent commercial for Campbell’s New Select Harvest Light (which is the sort of self-satirizing product name I’d expect to find in David Foster Wallace’s fiction) suggests that even if people don’t know what MSG stands for, they know that it’s bad—potentially bad enough to deter people from buying a particular brand. Reading from a Progresso Light can, blonde #1 gets through "monosodium" but stumbles on "glutamate"—fortunately, the rainbow coalition includes an Asian woman who can translate that jargon into something we all understand: "That’s MSG."
Although people may still associate it primarily with Chinese restaurant cooking, the Campbell’s ad hints at its broader prevalence—MSG and other forms of glutamic acid are omnipresent in processed foods. They’re especially likely to be found in foods designed to taste like things that have a lot of naturally-occurring glutamate (or similar molecules like inosinate or guanylate). Stock, broth, and bouillon often contain MSG, as does anything cheese-flavored or ranch-flavored, like Doritos, which actually contain five different forms of glutamate. I taste it the most in instant ramen and Chex Mix, but even though I know what it tastes like on its own, I can’t always tell when something contains it or not. When used sparingly, it may not even be possible to discern because whether the glutamate in a dish comes from a mushroom or a salt, once it’s dissolved in liquid or on your tongue, it’s the exact same molecule:
So even people who think it’s "bad" and expect to feel bad after eating it probably eat MSG, at least from time to time, without even knowing it, and without suffering any negative effects.
The Chinese Restaurant Syndrome Myth
The first person to suspect that MSG might be unhealthy was a Chinese-American doctor named Ho Man Kwok, who complained in a letter to the New England Journal of Medicine in 1968 that he experienced numbness radiating from the back of his neck down his arms, weakness, and heart palpitations after eating at Chinese restaurants. He had never experienced those symptoms after eating at restaurants in China, and hypothesized that they were due to either an excess of alcohol, sodium, or MSG in American Chinese cooking. The MSG explanation caught on, with one of the response letters estimating that as many as 30% of Americans regularly suffered bad reactions to MSG. The NEJM ran the letters with the title "Chinese Restaurant Syndrome," and by the next year, articles in Science and The New York Times were referring to the syndrome and its MSG etiology as verified facts:
Last year, the New York Times ran an article that attempted to set the record straight. They quoted the daughter of Chinese restaurant owners in New York City in the 1970s, who remembered the publicity around "Chinese Restaurant Syndrome" as a "nightmare":
“Not because we used that much MSG — although of course we used some — but because it meant that Americans came into the restaurant with these suspicious, hostile feelings.”
Chinese restaurants were among the first in the U.S. to use MSG, which was mass-produced in Japan beginning in the early 20th Century after a scientist named Kikunae Ikeda isolated glutamate from seaweed-based soup stocks. In the 1940s, it had become increasingly common in a number of processed foods and cooking styles around the world, including in the U.S. American soldiers who’d tasted Japanese army rations generally agreed that they tasted better, and the difference was widely attributed to MSG. As the war industries were refitted for peacetime manufacturing, including the greatly-expanded industrial food system, there was a greater need for flavor enhancers that would make food taste good even if it was canned or wrapped in plastic and transported long distances. MSG was great at that. It was also sold for home cooks to use under the brand name Accent, which is still available in the spice aisle of many grocery stores, and as a major component of Maggi sauce, a Swiss brand, and Goya Sazon seasoning blends, popular in the U.S. primarily with Latino/a and Caribbean immigrants.
It’s not entirely clear why Chinese restaurants were singled out, aside from the random chance of Kwok having weird feelings after eating at them. MSG was then, and still is, everywhere in American food. I suspect that it has something to do with a latent or repressed xenophobia. However, the success of Chinese restauranteurs and the fact that MSG didn’t really cause any physical symptoms were probably just as important—Cuban restaurants, where pork shoulder is often rubbed with a mixture of spices including MSG, weren’t nearly as common as Chinese restaurants. And if it had been called "chicken stock, Doritos, bologna, and Stove Top stuffing syndrome," that would have been far more difficult to accept for all the people who ate those things regularly without experiencing strange numbness and heart palpitations.
Which, of course, they generally don’t.
That’s Exactly what Forty Years of Research Has Found
No study has ever been able to find statistically significant correlations between the consumption of MSG and any of the symptoms associated with what was eventually re-named "MSG symptom complex" in 1995. According to a review article published in Clinical and Experimental Allergy in April 2009:
Descriptions of MSG-induced asthma, urticaria, angio-oedema, and rhinitis have prompted some to suggest that MSG should be an aetiologic consideration in patients presenting with these conditions…. Despite concerns raised by early reports, decades of research have failed to demonstrate a clear and consistent relationship between MSG ingestion and the development of these conditions.
Even studies involving self-identified "MSG-sensitive" subjects failed to find a significant increase in the frequency of MSG-attributed symptoms. In one study, only 2 of 130 self-identified "MSG-sensitive" subjects responded to MSG in 4/4 treatments. Additionally, no one’s ever found any clues as to why MSG, which is just the isolated form of a naturally-occurring amino acid salt, would cause numbness or heart palpitations.
The Fat Rat Caveat
A decade before Kwok’s letters on "Chinese Restaurant Syndrome" were published, some scientists began doing research on the effects of MSG on mouse brains. In 1968, a neuroscientist named John Olney, also known for his work on aspartame, attempted to replicate earlier studies where mice were fed massive amounts of MSG via feeding tube. The most dramatic result wasn’t in the brain, where he was looking, but their bodies: the mice fed MSG became "obese" (which had a different medical definition in 1968 than it does now, but still referred to unusual fatness). Given that glutamate registers as "deliciousness," one might assume that the difference was that the MSG-fed rats just liked their food a lot more and ate past satiety, but the MSG was administered by feeding tube, so taste shouldn’t have had anything to do with it. Based on his work, manufacturers voluntarily agreed to stop using MSG in baby food.
Subsequent studies have repeated the finding: mice and rats fed large amounts of MSG gain weight, and it’s not entirely clear why. As far as I can tell, the amount of food they consume is generally controlled, although if they have free access to water, perhaps they’re drinking like crazy to make up for amounts of MSG as high as 10 g per day, out of 100 g food total. However, the mice in most of the studies are fed amounts of MSG that far exceed what a human even surviving on instant ramen and Doritos alone would consume. There’s no evidence that the amounts typically consumed as a flavoring do any damage to people, no matter how young. People all over the world eat MSG all the time, both in processed foods and home-cooked foods, seemingly without suffering any negative effects. The growing consensus among people who’ve looked at the research is that
"toxicologists have concluded that MSG is a harmless ingredient for most people, even in large amounts" (Harold McGee On Food and Cooking 2004).
But it does seem like vast amounts of MSG can cause weight gain, sluggishness, and brain lesions in the retinal and hypothalamus regions. I’d advise against getting 10% of your daily intake of food from MSG.
A Nutritional Yeast Connection?
A random suspicion I haven’t been able to confirm is that MSG might be similar in many ways to nutritional yeast, the worst-named ingredient in the world. Nutritional yeast, also known as "nootch," is primarily used by vegans and some vegetarians as a flavoring agent that adds a slightly cheesy, deeply savory flavor to things ranging from popcorn to sauces to seitan. It also makes a tasty breading for tofu.
According to Wikipedia, "Modern commercial MSG is produced by [bacterial] fermentation of starch, sugar beets, sugar cane, or molasses." Nutritional yeast, on the other hand, is "produced by culturing yeast with a mixture of sugarcane and beet molasses, then harvesting, washing, drying it." Obviously whatever bacteria they use to ferment MSG results in a different product, but I wonder if they aren’t just different iterations of the same process. Ferment some sugar and molasses; in one case, extract the salt composed of sodium cations and glutamate anions and ditch the bacteria that do the fermenting; in the other, keep the yeast. Perhaps? If anyone knows more about the similarities or differences between the two, let me know.
It definitely seems like MSG doesn’t have any of the nutritional benefits of nutritional yeast, which is full of vitamins and minerals and protein, but it would still be a delightful irony to discover that the maligned substance behind a million Chinese restaurant disclaimers is related or comparable in any way to a crunchy, natural food bulk bin staple.
I don’t use MSG often, largely because I prefer the yeasty flavor and nutritional benefits of nootch, but I don’t think homemade chex mix is nearly as good without a teaspoon or so of MSG, and a little bit can perk up lackluster soups and sauces. Most grocery stores still sell Accent, and increasingly carry Maggi sauce and Goya Sazon as well. You can also buy giant bags of it at Asian markets. If you use too much, it will make food excessively salty and overpower subtler flavors, so use a light hand and taste as you go.
More tips on how to use MSG and recipes in future entries.