What exactly is MSG?
Monosodium glutamate, or MSG, is the sodium salt of glutamic acid, one of the most abundant and naturally occurring non-essential amino acids. It is the purest form of umami, the fifth basic taste alongside sweet, sour, salty, and bitter. Glutamate is naturally found in many whole foods, including tomatoes, mushrooms, aged cheeses like Parmesan, and even breast milk. The MSG used as a food additive is produced through the fermentation of plant-based ingredients like sugar cane, sugar beets, or corn, in a process similar to making yogurt or wine.
When consumed, the body processes the glutamate from MSG in the same way it processes glutamate found naturally in food proteins. It is an important neurotransmitter for the brain and nervous system, though dietary glutamate does not readily cross the blood-brain barrier. In the gut, glutamate serves as an important energy source for intestinal cells.
The origins of the MSG myth
MSG's infamous reputation can be traced back to a single letter published in the New England Journal of Medicine in 1968. A doctor described experiencing symptoms like numbness and palpitations after eating at a Chinese restaurant and speculated that MSG could be the cause. This correspondence, titled 'Chinese Restaurant Syndrome', became the basis for widespread, but scientifically unfounded, panic. The term was later updated to 'MSG symptom complex' as researchers found no consistent link to MSG consumption.
Subsequent investigations revealed that the letter was a hoax written on a bet, and the resulting public fear was amplified by xenophobic biases against East Asian cuisine. While American companies freely added MSG to processed foods like canned soups and chips without public backlash, the additive became a source of suspicion when associated with 'foreign' cooking.
Flawed science fueling fear
Early animal studies, which sensationalized MSG's potential for harm, were critically flawed. Instead of mimicking normal human dietary intake, they involved injecting massive doses of MSG directly into newborn mice. The results from these extreme experiments are not relevant to the typical oral consumption of MSG by humans. Later, more rigorous, double-blind, placebo-controlled human studies failed to consistently trigger reactions in self-identified MSG-sensitive individuals.
What modern science says about MSG safety
Today, the scientific consensus on MSG is clear: for the vast majority of people, MSG is a safe food additive. Major health organizations around the world have extensively reviewed the evidence and confirmed its safety:
- U.S. Food and Drug Administration (FDA): Considers MSG to be 'generally recognized as safe' (GRAS).
- Joint FAO/WHO Expert Committee on Food Additives (JECFA): Found no reason to set an acceptable daily intake limit, placing MSG in the safest category.
- Federation of American Societies for Experimental Biology (FASEB): Concluded that MSG is safe for the general population.
These bodies note that a small subset of people (less than 1%) might be particularly sensitive to very large doses of MSG (over 3 grams consumed without food). However, a typical serving of an MSG-enhanced food contains less than half a gram of the additive.
MSG vs. Table Salt
One of the most surprising facts about MSG is its potential to help reduce sodium intake. While table salt is 40% sodium, MSG contains only about 12% sodium. By using MSG in combination with salt, home cooks and food manufacturers can reduce the overall sodium content of a dish without sacrificing the savory flavor. This provides a potential strategy for improving public health outcomes related to high sodium intake, such as high blood pressure.
| Feature | Common Myth | Scientific Reality |
|---|---|---|
| Health Impact | Causes headaches, flushing, and other serious health issues like asthma and cancer. | Deemed safe by major health organizations. Reported symptoms are often linked to a nocebo effect, not MSG itself. Early, negative animal studies were based on unrealistic doses. |
| Composition | An artificial, dangerous chemical with no connection to natural foods. | The sodium salt of glutamic acid, a naturally occurring amino acid found in many foods. The body metabolizes it identically to natural glutamate. |
| Use in Food | Used exclusively in Asian cuisine to disguise poor-quality food. | Widely used in processed foods, fast food, and many cuisines globally. Provides a desirable savory flavor known as umami. |
| Sodium Content | Loaded with excessive sodium, making it a poor choice for heart health. | Contains only about one-third the amount of sodium as table salt and can be used to reduce total sodium intake. |
| Gluten Connection | The term 'glutamate' means it contains gluten. | There is no connection. Gluten is a different protein. Individuals with Celiac disease might react to wheat ingredients in a product, not the MSG. |
Putting MSG in the context of a healthy diet
For the average person, MSG is a harmless and effective flavor enhancer. The real issue is often not the MSG itself, but the nature of the foods it frequently appears in. Processed foods, snack foods, and fast food often contain MSG along with high amounts of fat, sugar, and sodium. Focusing on these ultra-processed products can distract from the bigger picture of a healthy diet.
Nutrition experts recommend prioritizing whole, unprocessed foods like fresh fruits, vegetables, and lean proteins. When cooking at home, adding a pinch of MSG can help reduce the amount of salt needed to achieve a savory taste, promoting lower sodium intake. This demonstrates how MSG can be a tool for healthier cooking rather than a source of harm.
Conclusion: Take the claims with a grain of salt
In conclusion, the longstanding stigma surrounding MSG is based on outdated, flawed, and culturally biased information rather than solid scientific evidence. Extensive research and review by major health authorities consistently find MSG to be a safe food additive for the general population, especially when consumed as part of a typical diet.
While a very small number of individuals may experience mild, short-term reactions to large doses of MSG consumed without food, these symptoms are rare and not life-threatening. The focus on MSG has largely been a distraction from the broader issue of poor nutritional quality in highly processed foods. Rather than demonizing a single ingredient, a balanced perspective is crucial. For most people, MSG is simply a useful culinary tool for enhancing flavor and, in some cases, for reducing overall sodium content in food.
