I am a viking.

“No MSG.”

This self-congratulatory proclamation adorns countless food packages around the Anglosphere. We’ve all seen it, on bags of potato chips or Chinese takeout menus, on instant noodles or those “just add meat and sour cream” Mexican meal kits. Oh thank heavens, we think when we spot it. This food is safe. This food is natural. This food is good.

MSG must be one of the most maligned chemical compounds in existence. Imagine a frozen pizza label, with an image of gooey cheese and glistening red pepperoni, enthusiastically marked “Contains MSG!” In terms of point-of-purchase advertising, it may as well say “Contains POISON!” Nobody would buy it, and the company would be laughed out of business.

But why? Why does everybody always gotta hate on the glutamate? The dubious badge of MSG-free honor has become so common and platitudinous – much like “low fat” or “organic” – that nobody seems to question what exactly is so wrong with MSG in the first place. It’s as though people assume that because a food producer would make a point to declare their product void of MSG, then it must be bad for you. Clearly this is silly; if potato chip packets suddenly started announcing that they were “low in vitamin C!” we would be skeptical of the reasoning behind such a claim. But we are so accustomed to the idea that MSG is unhealthy that we accept it unthinkingly.

Perhaps it is time for us all to reconsider MSG. There is so much hearsay surrounding it that it may be best to start with some clear, simple, possibly mind-blowing facts:

1. MSG is a naturally occurring compound present in many traditional foods; it is not an artificial flavoring nor a modern invention.
2. MSG has never been conclusively demonstrated to cause health problems in clinical studies; reports on its potentially negative effects are largely conjectural or anecdotal.
3. MSG can be added indirectly to food via products containing free glutamic acid, frequently rendering the “no MSG” label inaccurate, misleading, and/or pointless.
4. MSG is a very pure form of umami, and it can help make food taste fantastic.

First, a bit of chemistry. MSG is the initialism for monosodium glutamate, a common salt of glutamic acid, which is one of twenty amino acids that combine to form proteins in living organisms (other well-known proteinogenic amino acids are tryptophan and lysine). Glutamic acid is a non-essential amino acid, meaning that the body synthesizes it naturally from other proteins and uses it for things like metabolism and neurotransmission. Salts of glutamic acid such as MSG or monopotassium glutamate are used (directly or indirectly, via other foods that are naturally high in these salts) to add umami, or savoriness, to foods. Umami is a Japanese word that literally means “delicious flavor,” and it is now commonly recognized as the fifth basic taste, following bitter, salty, sweet, and sour. Umami’s position as the “fifth element” of gastronomy reminds me of quintessence, especially because it is so fundamental and omnipresent in cooking.

Next, a bit of history. In 1908 the Japanese chemist Kikunae Ikeda set to work trying to figure out what it was exactly that made his wife’s dashi so damn tasty. He began experimenting on konbu, the dried kelp that is used as the base of all Japanese master stocks. He discovered two things: 1) umami is a separate and distinct basic taste that contributes a savory character to food, and 2) glutamic acid and its salts are responsible for the umami in konbu dashi. He went on to patent monosodium glutamate under the name Ajinomoto (“essence of flavor”), which to this day is a top-selling global brand of MSG. (Years later, two other umami-producing compounds would be discovered, inosinate from katsuobushi and guanylate from shiitake mushrooms.) I was about to write that MSG has been enjoyed in Japan for over 100 years, but I caught myself because in actuality it has been enjoyed there, and here, and everywhere, for much, much longer. For as long as we have made stocks, cheeses and pickles and eaten peas, pork, and tomatoes, we have been relishing glutamic acid in all its myriad manifestations. Common, traditional foods particularly high in glutamate include soy sauce, miso, aged cheese, wine, beer, kimchi, scallops, asparagus, and yeast extracts like Vegemite and Marmite.

I had planned on trawling the internet for an assortment of common claims about the negative health effects of MSG, but as it turns out, I didn’t have to – this guy has done it all for me. His name is Steve and he seems to be quite an interesting fellow. Likes include freshly brewed coffee, spreading Christianity around Africa, and demanding to see Barack Obama’s birth certificate (here you are, sir). Dislikes? Messing with Texas, the antichrist, and most of all, MSG. Steve’s list of grievances with MSG is long, and his tone histrionic. The many, many side effects he attributes to it range from the familiar (migraines, obesity, “Chinese restaurant syndrome”) to the extreme (Alzheimer’s disease, cancer, death) to the bizarre (drunkenness, autism, night terrors). He compares MSG to marijuana and crack, and claims that “Cantonese food would taste like dish water” without it. He is an active geyser of misinformation and hysteria.

Steve’s claim that he has solved his own personal health problems by eliminating glutamates from his diet may well be true. (His claim that a friend becomes “literally drunk” from MSG is probably not quite so true.) If his tachycardia went away by cutting out excess glutamic acid from his diet, good for him – I have no way of disproving that. But almost all his other claims are unfounded, and in fact many are called into question by sources that he himself cites. It would take me ages to wade through them all, so let’s just take a couple at random:

One article linked from the “Truth In Labeling” site that supplies Steve with most of his information cites a 2002 study meant to provide evidence of MSG-induced damage to the nervous system. The study involved feeding rats a diet of MSG for three months, finding that the rats had a buildup of glutamic acid in the vitreous humor and suffered from retinal damage. Scary. But the citation itself says that the rats were fed 10 grams of MSG a day. If that doesn’t sound like much, consider that lab rats weigh 500 grams on average. Even if we’re generous and suppose these particular rats weighed one full kilogram, then the math makes this study practically inapplicable to humans. I weigh 75,000 grams, probably about average for a human male. The rats were getting 1 gram of MSG per 100 grams body weight; this means that for me to eat an equivalent amount I would need to ingest 750 grams daily. This is an impossible amount – imagine three sirloin steaks and you’re in the ballpark. Hell, most of us wouldn’t even want to eat that much steak on a day to day basis.

Another article correlates a rise in MSG consumption with the rise in obesity in the United States. Could MSG cause obesity? Perhaps – it does so in rats, according to some studies. But let’s look at these studies more closely. Here again we see an unrealistically high daily dosage of MSG being administered to the rats, 2.5-5 grams, or on a human scale, about 200-400 grams; and yet they describe this as “concentrations that only slightly surpass those found in everyday human food.” They then conclude that MSG “exhibits significant potential for damaging the hypothalamic regulation of appetite, and thereby determines the propensity of world-wide obesity.” Does it? Let’s look at this handy pie chart: China, Indonesia, Japan, and Thailand are among the largest consumers of MSG in the world. And what do these countries have in common? If you answered “they’re in Asia,” you’re correct. But more to the point, they aren’t fat countries; in 2007 the WHO reported that in China only 28.9% of the population was obese, in Indonesia only 16.2%, in Japan 22.6%, and Thailand 31.6%. Out of 194 countries they rank 148th, 175th, 163rd, and 144th for fatness, respectively. None of these countries could be said to have a serious obesity problem, which isn’t definitive evidence that MSG doesn’t contribute to a higher BMI, but it certainly suggests that the contribution is trivial if it exists at all. “Truth In Labeling” ignores more important factors even as it lists them: “overeating, inadequate diet, junk food, lack of exercise, psychological problems, genetics, and bad parenting.”

What I glean from all this research is that MSG is probably slightly neurotoxic, but only in concentrations far beyond what a normal person would consume. I could be wrong, and if I saw conclusive evidence that MSG causes dementia or nightmares or blindness or whatever then I would admit it. But so far I have yet to see that evidence. To people like Steve who claim all manner of personal health problems brought on by MSG, I would simply shrug and say, “sucks to be you.” I think most of us would agree that there’s nothing inherently wrong with with peanuts or lactose, and yet some people have peanut allergies, and some are lactose intolerant. Sucks to be them. And if you think that MSG gives you headaches or diarrhea, then I’m afraid it sucks to be you, too.

Why does it suck to be you? Because MSG is a wonderful, wonderful thing to cook with. It has been pointed out that MSG is only necessary when the food it’s applied to is bland on its own. There is some truth to this; MSG can add a moreish quality to food that would otherwise be fairly flavorless, which is why it’s found in so many industrially manufactured food products. But then just imagine what it can do to food that’s already good. I am reminded of my days in Japan. At some point it dawned on me why the plain grilled pork belly at my usual yakitori bar tasted uncommonly delicious; why Japanese mayonnaise is far superior to the American version; and why Parmesan cheese tastes surprisingly good in ramen. It’s because the pork, the mayo, and the cheese all contain MSG, which makes them exceptionally mouthwatering, savory, and bold.

Just last night I made some BLTs, and after dinner I had some leftover tomatoes and avocados (they were actually BLATs). I decided to sprinkle on some MSG and gobble them up. Somehow it just made them taste more of themselves – fresher, sweeter, brighter. It’s similar to adding salt, but different – it adds a depth and a satisfying aftertaste that can only be described as a big boost of umami. Of course there are other ways to add umami to food: dashi, soy sauce, Parmesan, ketchup, etc. But MSG is the most pure. It allows the original ingredients to shine without any interference from superfluous flavors, and that’s what makes it so lovely.

You can try an experiment at home. Get yourself an ingredient – meat, fish, vegetables, it doesn’t matter. Divide it into four portions. Leave one unseasoned. Season one with salt. Season one with soy sauce. Season the last one with MSG. (You can get it at Asian grocery stores, or even at mainstream supermarkets if you look carefully.) Cook them all the same way, any way you like, then taste them, and you’ll get a good idea of what MSG does and why it can be so useful. (As a twist to the experiment, find a friend who claims to be MSG sensitive, blindfold them, give them the food and see how they react.)

As cooks and eaters we are denying ourselves a tremendously useful ingredient for no good reason. Of course there may be minor health risks from eating too much MSG, as there are from eating too much of just about anything. But in terms of flavor, it takes us where ordinary salt can only dream of going, into the deep, shadowy, sensuous world of umami. If MSG is risky, then it’s a risk I’m willing to take.

On their main page, the authors of “Truth In Labeling” proudly and prominently display a catchphrase that’s as pithy as it is desperately stupid:

If MSG isn’t harmful, why is it hidden?

I retort and close with a quotation that’s equally pithy (and a little glib) but much more incisive:

If MSG is so bad for you, why doesn’t everyone in Asia have a headache?

Further reading:

Dashi and Umami: The Heart of Japanese Cuisine by Yukiko Takahashi

“The Day I Ate as Many E Numbers as Possible” by Stefan Gates, BBC News