The Origins of the MSG Controversy
The widespread stigma surrounding MSG is not based on sound scientific evidence but rather on a historical misunderstanding fueled by prejudice. The controversy began in 1968, sparking decades of unverified claims and food fear.
The 'Chinese Restaurant Syndrome' Letter
The genesis of MSG's bad reputation can be traced to a letter published in the New England Journal of Medicine in 1968. A doctor, Robert Ho Man Kwok, described symptoms like numbness, weakness, and heart palpitations after eating at a Chinese restaurant and speculated that MSG could be the cause. Though his letter also mentioned cooking wine and salt as possibilities, the media latched onto MSG, coining the term "Chinese Restaurant Syndrome" (CRS).
Flawed Early Research
Following the CRS letter, several poorly designed studies seemed to support the fear surrounding MSG, further cementing its negative image. One infamous animal study involved injecting extremely high doses of MSG directly into the brains of infant mice, leading to brain lesions. This research, however, was highly misleading as the dose and method were irrelevant to normal human oral consumption. These early studies lacked proper controls, used excessive doses, and often employed irrelevant administration methods, leading to biased and inaccurate conclusions.
Xenophobia and Cultural Bias
As food historian Ian Mosby has detailed, the fear of MSG and CRS was deeply entangled with xenophobia and long-standing biases against Asian immigrants and their cuisine. The suspicion directed at Chinese food, in particular, was part of a larger history of viewing foreign cuisines as dangerous or dirty. This cultural bias created a double standard, as MSG was widely used in processed American foods like canned soups and chips without similar scrutiny. Famous chefs and food personalities, like Anthony Bourdain, have publicly pointed out the xenophobic roots of the MSG myth.
The Scientific Consensus on MSG Safety
Modern, high-quality scientific evidence has consistently affirmed MSG's safety for most people when consumed in normal dietary amounts.
Regulatory Body Findings
Major health and food safety organizations worldwide have reviewed MSG's safety and deemed it safe. The U.S. Food and Drug Administration (FDA) classifies MSG as "Generally Recognized As Safe" (GRAS). The Joint FAO/WHO Expert Committee on Food Additives (JECFA) also considers it safe, establishing an acceptable daily intake (ADI) that far exceeds typical consumption levels.
Modern Double-Blind Studies
Crucial to debunking the myth were double-blind, placebo-controlled studies conducted on individuals who reported sensitivity to MSG. In these studies, where participants did not know if they were consuming MSG or a placebo, researchers failed to consistently trigger the reported symptoms. When reactions did occur, they were often inconsistent and not reproducible.
MSG Symptom Complex
While CRS is not a valid diagnosis, a very small subset of the population (less than 1%) may experience a mild, transient reaction to large doses of MSG, typically 3 grams or more consumed on an empty stomach. This is not an allergic reaction but has been termed "MSG symptom complex" (MSC) and may involve headaches, flushing, or numbness. This reaction is extremely rare under normal eating conditions.
The Chemical Reality of Glutamate
MSG is not some mysterious, toxic chemical but rather a purified form of glutamate, a common amino acid found throughout nature.
Natural vs. Added Glutamate
It is chemically indistinguishable from the glutamate found naturally in many protein-rich foods. Your body metabolizes both sources of glutamate identically.
Foods naturally high in glutamate
- Parmesan cheese
- Tomatoes and tomato paste
- Soy sauce
- Mushrooms
- Cured meats
- Seaweed
How MSG Functions
MSG's purpose is to enhance the savory flavor known as umami. By intensifying this taste, it can make food more palatable, particularly in low-sodium dishes. MSG contains about one-third the sodium of table salt, so using it can actually help reduce overall sodium intake without sacrificing flavor.
Why Do Restaurants Still Say "No MSG"?
Despite the clear scientific evidence, the legacy of fear continues. This often manifests in misleading menu claims.
Customer Demand
Many restaurants, particularly Chinese and Asian restaurants, added "No MSG" signs decades ago to appease a fearful public. Today, the practice persists because some customers still demand it, even if their fears are unfounded.
Misleading Marketing
Food manufacturers and restaurants may use ingredients that are naturally high in glutamate, such as yeast extract or hydrolyzed proteins, and then label their product as having "No Added MSG." This claim is technically true but can be misleading to consumers who believe they are avoiding all forms of glutamate.
Quality of Ingredients
For high-end or traditional culinary practices, some chefs argue that relying on fresh, high-quality ingredients allows them to build complex umami flavors naturally, making the addition of MSG unnecessary. This is a matter of technique and preference, not a reflection of MSG's safety.
Natural Glutamate Sources vs. Added MSG
| Feature | Naturally Occurring Glutamate | Added Monosodium Glutamate (MSG) |
|---|---|---|
| Source | Found in protein-rich and umami-rich foods like meat, cheese, and vegetables. | Produced by the fermentation of carbohydrates like sugar cane or molasses. |
| Chemical Identity | Chemically identical to added MSG once digested. | Chemically identical to natural glutamate. |
| Processing | Present within the complex matrix of whole foods. | Purified and crystallized as a food additive. |
| Digestion | Metabolized identically by the body. | Metabolized identically by the body. |
| Public Perception | Generally viewed as a healthy component of natural food. | Often viewed with suspicion due to historic misinformation. |
Conclusion
The notion that MSG is not allowed or is inherently bad is a pervasive myth rooted in historical ignorance and prejudice, not modern science. Health authorities have confirmed its safety at normal dietary levels, and your body processes its glutamate no differently than the glutamate in your favorite cheeses and tomatoes. While catering to outdated consumer fears, some restaurants and brands perpetuate this misconception through misleading marketing. The real story behind why MSG is avoided reveals a complex history where science was overshadowed by unfounded bias, a history that is now being rewritten by a better understanding of food chemistry and flavor. Read more about the FDA's stance on MSG here: Questions and Answers on Monosodium glutamate (MSG).
Disclaimer: While MSG is generally safe, those with a confirmed sensitivity should limit intake and consult a medical professional. If a processed food contains MSG, it is often a sign that it is an unhealthy, highly processed item best consumed in moderation, but the MSG itself is not the toxic element.
