What is MSG (Monosodium Glutamate)—and is it Safe to Eat?
Here's what you need to know about MSG, a common food additive that far too often gets a bad rap.
You've probably heard that MSG is bad for you, and that eating it in food causes side effects like headache, nausea, and rapid heartbeat. Admittedly, the full name—monosodium glutamate—sounds a bit frightening. But while MSG is widely scrutinized, should we really be worrying about it?
The truth is, avoiding MSG can be difficult. It's often used in Asian cooking, but it's also found in processed foods such as potato chips and salad dressing. And with plenty of opinions and research out there, separating the facts from the myths can be overwhelming. So let's take a close look at MSG, including what it is, what foods contain it, how safe it is, and whether its bad rap is actually deserved.
What is MSG?
MSG is a food additive used to enhance flavors in food. In its purest form, it resembles white crystals and is relatively tasteless. Combine MSG with salty- or sour-tasting foods, however, and the flavors perk up instantly. MSG imparts a distinctive, umami flavor, a taste sensation best described as savory, meaty, and deeply satisfying. Umami is one of the five basic tastes along with salty, sweet, bitter, and sour.
Quite simply, umami is what makes foods like lasagna, burgers, and pizza comforting and craveworthy. But what exactly is happening here on a chemical level? Tomatoes, beef, and cheese—the main ingredients in these foods—contain glutamate, an amino acid that's naturally occurring in both animal and plant proteins.
In fact, the human body produces glutamate on its own (through breast milk), and most foods such as grains and legumes contain varying amounts of it as well. Some of the strongest sources of glutamate include wheat (grains, flours, pasta), seaweed, peanuts, turkey, salmon, cheese, tomatoes, mushrooms, garbanzo beans, and sunflower seeds.
MSG was first discovered in the early 1900s by a Japanese chemist named Kikunae Ikeda who extracted glutamate from seaweed. Realizing the flavor-enhancing potential of glutamate, Kikunae coined his discovery "umami," which means "savory taste" in Japanese.
In looking for a way to market his discovery, Kikunae found that adding salt (sodium) to glutamate transformed into a shelf-stable, water soluble powder. This "MSG seasoning" could enhance everything from soups to stews to sauces. Ikeda acquired a patent for his invention and sold it under the name Ajinomoto, which is still the leading producer of MSG in Japan today. In the US, you'll commonly see MSG seasoning sold under the brand Accent Flavor Enhancer.
MSG in Food
Today, MSG may be used in all sorts of processed food products to enhance flavor at a lower cost. Below are examples of common processed foods that may contain MSG:
Flavored chips (such as Doritos and Pringles)
Soy sauce packets
Bottled salad dressing
Hidden Sources of MSG in Food
The FDA requires any food with added MSG to be clearly listed as "monosodium glutamate" on package labeling. However, some ingredients—such as yeast extract or maltodextrin—naturally contain glutamates, the main compound of MSG. Other examples of ingredients with naturally-occuring MSG are hydrolyzed vegetable protein, autolyzed yeast, hydrolyzed yeast, soy extracts, and protein isolates. Because the FDA does not require these ingredients to be labeled as "naturally-occuring MSG," identifying them can be tricky.
You may find naturally-occuring MSG in processed foods like frozen dinners and even veggie burgers. Even if the label states "no added MSG" on the label, keep in mind that this is not the same as "No MSG." If naturally-occuring MSG is of concern to you, make sure to read ingredients lists closely.
MSG in Chinese Food
You've probably seen MSG associated with something called "Chinese restaurant syndrome." While outdated, this term once referred to the symptoms—body tingling, heart palpitations, nausea, warmth, headaches, and more—that some people experienced after eating Chinese food.
Given the Japanese origins of MSG, its link to Chinese food is a bit perplexing. How exactly did it all start? In 1968, The New England Journal of Medicine published a letter called Chinese Restaurant Syndrome from a doctor named Robert Ho Man Kwok. In the letter, Kwok describes experiencing bizarre, allergy-like symptoms soon after eating at Chinese restaurants. Kwok speculates that his symptoms may have been caused by common ingredients used in Chinese restaurants during the 1960s, namely soy sauce, cooking wine, salt, and MSG.
Kwok's letter, coupled with a series of inconclusive scientific studies, contributed to MSG's reputation as a dangerous food additive that lurked in Chinese restaurants. Today, the stigma against MSG and Chinese food has lessened significantly, especially as umami has gained wide recognition as one of the five tastes. But does Chinese food still contain MSG? Potentially, yes—and you're more likely to see MSG in soups and sauces that heavily rely on umami flavors such as pho, miso soup, or oyster sauce. If you're concerned about MSG, you can always request to have your meal prepared without it.
Lastly, MSG is not just limited to Chinese or Asian restaurants. MSG is also used in foods at popular fast food restaurants, typically in fried chicken and dipping sauces. For example, a Chick-Fil-A Chicken Sandwich contains MSG in both the seasoning and the breading on its chicken breast.
Is MSG Bad for You?
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The FDA considers MSG "generally recognized as safe," (GRAS) meaning that it is considered safe under the conditions of its intended use. While some people claim that MSG gives them a headache, the American Academy of Allergy, Asthma, and Immunology does not consider MSG as a food allergen. The FDA has received anecdotal reports of MSG side effects, but the government agency isn't able to confirm that MSG is the root cause of symptoms.
If MSG is not an allergen, why do some people still report side effects from it? "Research for the most part suggests that MSG is safe," says nutritionist Carolyn Williams PhD, RDN. "However, there is validity to individuals who believe they are sensitive to MSG. These individuals may have an intolerance to MSG that triggers subtle, yet annoying, side effects like headaches or numbness," asserts Williams.
Williams stresses that while MSG sensitivities are real, there's just no lab test to verify them—which makes identifying them a gray area. "Food sensitivity or intolerance doesn't usually trigger an immune response and isn't life-threatening like a reaction to a food allergy. Because of this, and the fact that symptoms are vague, food sensitivities are hard to identify or diagnose with lab tests." According to Williams, the best way to determine if you have a sensitivity to MSG is to simply eliminate all food containing MSG to see if your symptoms disappear.
Is MSG Gluten-Free?
While the glutamate in MSG may sound similar to gluten, it does not cause an allergic reaction on its own. The FDA asserts that MSG is naturally gluten-free—and that those with Celiac disease can safely consume it. In fact, the modern process for manufacturing MSG has nothing to do with gluten at all. Instead, MSG is made through the fermentation of sugars and starches like sugar cane, sugar beets, and molasses.
However, just because MSG itself is gluten-free, this doesn't mean that a product containing it is also gluten-free. For example—soy sauce, a natural source of glutamate, is not considered gluten-free because it contains wheat as an ingredient.
Is MSG Good for You?
The potential health benefits of MSG are largely overshadowed by its negative reputation. According to the Academy of Nutrition and Dietetics, using MSG instead of salt to add flavor may help some people cut down on their sodium intake. This is because MSG contains one third of the sodium as salt—and using just a little will go a very long way.
In fact, AND states that using MSG in place of salt in a recipe can decrease the sodium content by 20 to 40 percent. Using MSG may also make food more enjoyable for those with weakened taste buds, such as the elderly—and it may even help prevent nutritional problems caused by a lack of interest in food.
The Verdict on MSG: There's no reason to fear MSG. Extensive research asserts that MSG is a safe food additive for most people to consume, but some people may be more sensitive to it than others. Do your research, check package labels, and make an informed decision about whether you want to consume or avoid foods with MSG.