Monosodium L-glutamate, commonly known as MSG, is a widely used food additive recognized for its ability to enhance savory flavors. It is also a compound that occurs naturally in many foods people consume regularly. This substance is closely associated with the taste known as umami, which is often described as a pleasant, savory, or meaty taste.
What is Monosodium L-Glutamate?
MSG is chemically defined as the sodium salt of glutamic acid, an amino acid that serves as a building block of protein. The discovery of MSG and its connection to the umami taste dates back to 1908, when Japanese professor Kikunae Ikeda isolated glutamic acid from kombu seaweed.
This discovery led to the commercial production of MSG, which is now manufactured through the fermentation of carbohydrate sources such as sugar beet, sugar cane, or molasses. The glutamate in MSG is chemically identical to the glutamate found naturally in food proteins, meaning the body metabolizes both forms in the same way. MSG functions by enhancing the savory notes already present in food, rather than adding a flavor of its own.
Glutamate, the active component of MSG, occurs naturally in high concentrations in many common foods. Examples include aged cheeses like Parmesan, ripe tomatoes, mushrooms, various meats, and seafood. Seaweed, fermented products like soy sauce, and even breast milk also contain naturally occurring glutamate. The presence of free glutamate in these foods contributes to their inherent savory taste, making MSG a familiar compound in many global cuisines.
Understanding the Safety of MSG
The safety of MSG has been a subject of public discussion, particularly due to the emergence of the term “Chinese Restaurant Syndrome” in the late 1960s, which linked MSG to a range of mild, transient symptoms. However, extensive scientific research conducted over decades has provided a clear consensus from major health organizations worldwide regarding MSG’s safety.
The U.S. Food and Drug Administration (FDA) classifies MSG as “Generally Recognized As Safe” (GRAS), a designation also applied to common substances like sugar and salt. The Joint Expert Committee on Food Additives (JECFA) of the United Nations Food and Agriculture Organization (FAO) and the World Health Organization (WHO) has also affirmed MSG’s safety, concluding that its dietary intake as an additive does not pose a health hazard. These organizations have found no evidence linking MSG to serious or long-term health problems in the general population.
While some individuals report experiencing mild, temporary reactions such as headaches, sweating, flushing, or chest tightness after consuming large doses of MSG, these reactions are rare and not consistently reproducible in controlled scientific studies. For instance, studies involving self-proclaimed MSG-sensitive individuals have not been able to consistently trigger symptoms when MSG is administered in a blinded fashion. These reported symptoms are not considered allergic reactions and may, in some cases, be attributed to other food components or a placebo effect. A typical serving of food with added MSG usually contains less than 0.5 grams, whereas reported reactions typically occur with doses of 3 grams or more consumed on an empty stomach.
Where MSG is Found and How It’s Labeled
MSG is frequently added to a variety of processed foods to enhance their savory flavor. Common categories include processed snacks like chips and crackers, canned soups, frozen meals, and seasoning blends. It is also used in many restaurant foods, including fast food items and Asian cuisine.
When MSG is added directly to packaged foods, the FDA requires it to be listed explicitly in the ingredient panel as “monosodium glutamate”. However, consumers should also be aware of other ingredients that naturally contain or produce free glutamate during processing, which contribute to umami but are not labeled as “MSG”. These include hydrolyzed vegetable protein (HVP), yeast extract, autolyzed yeast, soy extracts, and protein isolates.
The presence of these ingredients on a food label indicates natural glutamate content, not necessarily added MSG, although they can contribute to a similar flavor profile. Claims like “No MSG” or “No added MSG” on packaging are not permitted if the food contains ingredients that naturally contain MSG.