In 1968, a letter to the editor in the New England Journal of Medicine noted that when the writer and his friends would go to Chinese restaurants, they would often have a certain set of unpleasant symptoms afterward: numbness in the back and arms, palpitations, a general feeling of weakness. This wasn’t a scientific paper or a medical paper. It was a letter to the editor—which anybody can write—proposing a question. The writer was a doctor, but not a specialist in anything that would have to do with MSG chemistry. He wondered whether there was a connection between what he and his friends ate at the Chinese restaurant and their symptoms.
He also noted that Chinese restaurants often used MSG as a seasoning, and that that was one thing that distinguished Chinese restaurants from other restaurants—so consuming large quantities of MSG might have had some connection to that set of symptoms. The journal gave his letter the title “Chinese Restaurant Syndrome,” and then printed a number of follow-up letters in later issues under the same title. That’s part of the reason that these anecdotal letters to the editor got more attention than they deserved. The media picked up on the catchy title, neglected the fact that the letters were mostly speculation, and encouraged the belief that MSG was known to cause these symptoms in people who go to Chinese restaurants.
The connection with MSG went overnight from being a question to being considered very likely. And then what ensued was a period of decades in which people became concerned about MSG, and many more people decided that they had Chinese Restaurant Syndrome. They became more sensitive to unpleasant feelings of all kinds after eating, and then companies and doctors and governments all over the world began to study the effects of MSG on the human body.
MSG is a common ingredient in foods, and not just in Chinese restaurants; it occurs naturally in many of the foods we love.
MSG is an acronym for monosodium glutamate, the sodium salt of glutamic acid. We’re familiar with sodium from salt, which is sodium chloride. That’s innocuous enough. It’s the glutamic-acid part that makes MSG what it is. Glutamic acid is an amino acid, which are the building blocks of proteins. Our bodies are built out of proteins. The muscle fibers that move our bodies are proteins, the tiny motors that move molecules within each of our cells are proteins.
But the important thing to know is that, hundreds and hundreds of studies later, there is no evidence that MSG causes the symptoms of Chinese Restaurant Syndrome. This was an unfortunate episode that should teach us a lot about carefully reading proposals of cause and effect between something we eat and some effect that it might have. Eating is a very complicated subject, diet is a very complicated subject, and foods are very, very complicated materials. It’s usually very difficult to draw a straight line from one ingredient to a particular symptom or a particular problem. In the case of MSG, the record is about as clear as it can be: there is no connection between consuming MSG in any form and the symptoms that are often called Chinese Restaurant Syndrome.
If you love tomatoes, one of the reasons you love tomatoes is that they contain much more natural MSG than many other vegetables. If you love aged Parmesan cheese or if you love an aged steak, one reason you love those foods is that the aging process breaks the proteins down into amino acids, MSG included. Parmesan cheese and aged beef have some of the highest levels of MSG of any food we eat, and that’s part of what makes them delicious.
The flavor of MSG is so distinctive and so important that it has its own name, one that’s become one of the most talked-about things among professional cooks in the last couple of decades. That name is umami. It’s a Japanese term without a clear, simple definition. It’s often equated with “deliciousness” or “savoriness.” We use a Japanese term because it was the Japanese who discovered this very basic taste. A scientist studying the flavor of Japanese broths, dashis, found that the key element was monosodium glutamate, which is present in very high quantities in a particular seaweed, konbu, that is used to make the broth.
So MSG was discovered to be a natural ingredient in the standard soup preparation in Japan. Nothing modern, nothing biochemical, nothing industrial about it. Over the next few years, other Japanese scientists found other molecules with umami effects present in cured fish, in shellfish, and in shiitake mushrooms.
Decades ago, the Japanese proposed that umami was a basic taste. Western scientists resisted that idea, and said that the proof would be to find a particular receptor on our taste buds specific to MSG. Well, exactly that happened about ten years ago. The taste of MSG is a basic taste, and what that means for cooks is that when you’re cooking and you’re trying to develop a dish that is fully flavored, you can’t overlook umami. You can’t overlook MSG and its fellow umami molecules.
What that means practically is that if you’re developing a dish, or if you’re refining a dish or seasoning it at the last minute, you want to ask yourself if you’re getting that flavor into the dish in balance. Taste comprises sweet, sour, salty, bitter, and umami. MSG is a big part of the story, but it’s not the only part.
You can ask yourself as you’re putting a dish together whether you’re including ingredients that will give you some umami: tomatoes, Parmesan cheese, aged meats, browned meats, mushrooms, dashi, and many things that have been fermented for a long time (fish sauce, soy sauce, even things like wine vinegars or sherry vinegars). All of these will deepen and fill out the flavor. And if eating them causes any discomfort, it’ll be the So-Good-I-Couldn’t-Stop Syndrome.