The term “Chinese Restaurant Syndrome” (CRS) is a historical, non-medical label used to describe physical sensations reported after consuming Chinese food. The concept originated from an anecdotal letter published in the New England Journal of Medicine in 1968. This account described symptoms experienced after eating at a Chinese restaurant, setting the stage for a controversy that has persisted for decades. Public focus quickly centered on one specific food additive as the cause.
Characterizing the Symptoms
Individuals who reported CRS described a variety of acute, subjective physical reactions occurring shortly after a meal. The sensations were intense but temporary, typically subsiding within an hour or two. Common complaints included numbness or tingling, often beginning at the back of the neck and radiating into the arms and back.
Other reported symptoms included headache, facial pressure, and flushing of the skin. Individuals also reported sweating, general weakness, and heart palpitations. These wide-ranging, self-reported physical sensations led to the creation of the term CRS to categorize the post-meal experience.
The Implication of Monosodium Glutamate
The primary ingredient historically targeted as the cause of these symptoms is Monosodium Glutamate (MSG). MSG is the sodium salt of glutamic acid, one of the most abundant naturally occurring non-essential amino acids. It functions as a flavor enhancer, providing the savory taste known as umami.
MSG is used commercially worldwide in a vast number of processed foods, including canned vegetables, soups, salad dressings, and processed meats. Glutamate is also naturally present at high levels in foods like aged cheese, tomatoes, mushrooms, and cured meats. The taste-enhancing properties of MSG are the same as the free glutamate found naturally in these common ingredients.
Despite its widespread use, the 1968 letter caused MSG to be almost exclusively associated with Chinese cuisine. This led to a public perception of MSG as an unnatural or potentially harmful chemical. The U.S. Food and Drug Administration (FDA) classified MSG as “Generally Recognized As Safe” (GRAS) in 1959, a designation it shares with common substances like salt and baking powder.
Scientific Investigation and Current Consensus
Following public concern, scientific bodies began rigorous testing of the link between MSG and the reported symptoms. The most reliable method for testing food sensitivities is the double-blind, placebo-controlled challenge. In this study type, neither the subject nor the researcher knows if the subject receives MSG or an inert placebo, eliminating expectation bias.
Large-scale, controlled studies have consistently failed to confirm a reproducible link between MSG consumption and symptoms in the general population. International bodies like the Joint Expert Committee on Food Additives (JECFA) and the FDA have concluded that MSG is safe for consumption at customary levels. A 1995 report prepared for the FDA by the Federation of American Societies for Experimental Biology (FASEB) also affirmed MSG’s safety.
The FASEB report noted that a small, sensitive subgroup might experience temporary, mild symptoms when consuming very large doses (three grams or more) of MSG without food. This scenario is highly unlikely in a typical meal, as a usual serving contains less than 0.5 grams of added MSG. Furthermore, when MSG was consumed with food, reactions were not observed, even in individuals who believed they were sensitive.
The medical community has largely moved away from the term “Chinese Restaurant Syndrome” due to its lack of scientific validation. Instead, “MSG Symptom Complex” is sometimes used to acknowledge the mild, transient reactions some individuals report. The scientific consensus is that reported reactions are not a hypersensitivity or allergic response but are likely psychosomatic or related to other factors in the meal.
Dietary Management and Labeling
For consumers who believe they are sensitive to MSG, careful dietary management is a pragmatic approach. Managing intake requires familiarity with how MSG and free glutamate are disclosed on food labels. When MSG is added directly as an ingredient, the FDA requires it to be listed as “monosodium glutamate.”
Glutamate occurs naturally in ingredients added to enhance flavor, and manufacturers are not required to label these ingredients as containing MSG. Consumers should look for other common names that indicate the presence of free glutamate:
- Hydrolyzed vegetable protein
- Autolyzed yeast
- Yeast extract
- Hydrolyzed protein
These components are derived from broken-down protein, which releases glutamate.
When dining out, communicate dietary concerns directly with the staff, especially at restaurants that do not explicitly state they are MSG-free. Asking specifically for dishes prepared without added MSG can help sensitive individuals avoid the ingredient. Focusing the diet on whole, unprocessed foods is another effective way to naturally limit the consumption of added flavor enhancers.