Monosodium Glutamate (MSG) is a flavor enhancer that has been widely used for roughly 100 years (
In addition to being naturally present in certain foods, it’s a common food additive in Chinese recipes, canned vegetables and soups, and other processed goods.
For years, MSG has been viewed as an unhealthy ingredient. However, newer research questions the accuracy of its purported adverse effects on human health.
This article examines MSG and what current evidence has to say about its health effects.
MSG is short for monosodium glutamate.
It’s a flavor enhancer derived from L-glutamic acid, which is naturally present in many foods. L-glutamic acid is a nonessential amino acid, meaning that your body can produce it by itself and doesn’t need to get it from food (
It’s made by fermenting carb sources like sugar beet, sugar cane, and molasses (
Besides MSG, other umami compounds include inosine 5’-monophosphate (IMP) and guanosine 5’-monophosphate (GMP) (
The flavor-enhancing effects of MSG are due to its umami taste, which induces salivary secretion. In other words, umami flavors make your mouth water, which can improve the taste of food (
MSG is derived from L-glutamic acid, an amino acid found in your body and many foods. It’s a popular food additive used to enhance flavor. It can be used to reduce overall sodium intake when used in place of salt.
MSG got its bad reputation in the 1960s when Chinese-American doctor Robert Ho Man Kwok wrote a letter to the New England Journal of Medicine explaining that he got sick after consuming Chinese food.
He wrote that he believed his symptoms could have resulted from consuming either alcohol, sodium, or MSG. This sparked a host of misinformation about MSG, which was likely related to then-present biases against Chinese immigrants and their cuisine (
The letter led to the designation of Kwok’s symptoms as the “Chinese restaurant syndrome,” which later became the “MSG symptom complex” (MSC) (
Later on, numerous studies backed MSG’s bad reputation, stating that the additive was highly toxic (
However, current evidence questions the accuracy of previous research for several reasons, including (
- a lack of adequate control groups
- small sample sizes
- methodological flaws
- a lack of dosage accuracy
- the use of extremely high doses that far exceed those consumed in typical diets
- the administration of MSG via routes with little to no relevance to oral dietary intakes, such as injections
Today, health authorities like the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the Food and Drug Administration (FDA), and the European Food Safety Association (EFSA) consider MSG to be generally recognized as safe (GRAS) (
They have also determined an acceptable daily intake (ADI) of 14 mg per pound (30 mg per kilogram) of body weight per day. This is far more than the amount you’d typically ingest following a normal diet (
While racial biases and older research implied that MSG was a toxic additive, current evidence and health authorities recognize it as safe.
MSG has been linked to obesity, metabolic disorders, brain toxicity, and MSC. Here’s what the current research has to say about these purported downsides (
Effect on energy intake
Older evidence states that by making food taste better, MSG disrupts the signaling effect of the hormone leptin in your brain. Leptin is in charge of telling your body that you’ve had enough to eat. In turn, this is said to increase your calorie intake (
However, the current data on MSG’s effects on energy intake is contradictory. Some studies have found that it may reduce appetite, while others support the idea that its flavor-enhancing properties could lead to overeating (
The contradictory results might have to do with the nutritional profile of a meal. For example, eating MSG-enhanced, high protein meals has been linked to increased feelings of fullness, while this link hasn’t been observed with high carb meals (
However, this could also be because protein is the most filling macronutrient — it might not have anything to do with the MSG content (
Ultimately, more research on the connection between MSG and energy intake is needed.
Obesity and metabolic disorders
MSG has been associated with an increased risk of metabolic disorders, primarily due to animal studies that have linked the additive to insulin resistance, high blood sugar levels, and diabetes (
However, previous research has used imprecise methods for determining MSG consumption, such as injections instead of oral doses. This could lead to effects on the brain that are not associated with dietary intake (
What’s more, the current data is contradictory. For instance, newer animal studies have found an association between umami substances and anti-obesity effects. In contrast, other animal and human studies show no effect on body weight (
While it appears that typical dietary MSG intakes are unlikely to influence body weight or fat metabolism, more human studies are needed (
Effect on brain health
In fact, research shows that once ingested, MSG is completely metabolized in your gut. From there, it either serves as an energy source, is converted to other amino acids, or is used in the production of various bioactive compounds (
Overall, no compelling evidence suggests that MSG alters brain chemistry when consumed in normal amounts.
Some people may be sensitive
MSC is characterized by symptoms similar to those described by Dr. Kwok in his letter. They include weakness, flushing, dizziness, headache, numbness, muscle tightness, difficulty breathing, and even the loss of consciousness (
Keep in mind, though, that a 3-gram dose is a high one. A typical serving of an MSG-enriched food contains less than half a gram of the additive, so consuming 3 grams at one time is highly unlikely (
Current evidence debunks most of the beliefs that consider MSG harmful or dangerous. However, in some cases, research findings are contradictory, and further studies in humans are needed.
- Animal-based protein: chicken, beef, salmon, mackerel, scallops, crab, shrimp
- Cheese: Parmesan, Emmenthal, cheddar, Roquefort
- Vegetables: tomatoes, onions, cabbage, green peas, spinach, mushrooms, broccoli
- Processed meats: pepperoni, bacon, pastrami, sausages, salami
- Sauces and dressings: soy sauce, ketchup, mustard, mayonnaise, barbecue sauce, salad dressings
- Premade and packaged foods: canned soups, canned tuna, frozen meals, crackers, potato chips, flavored snacks
- Condiments: seasoning blends, rubs
MSG is naturally present in many foods, including some cheeses, meats, and vegetables. It’s also added to some processed and fast-food items.
MSG is a flavor-enhancing additive that’s also naturally present in many protein-rich foods, cheeses, and vegetables.
Although it was considered a toxic ingredient during the 1960s, current evidence has dispelled that myth, indicating that MSG is safe when consumed in moderate amounts.
Still, you shouldn’t eat excessively large doses or consume it if you experience adverse reactions.
Just one thing
Try this today: There’s no compelling reason to avoid MSG if you don’t experience side effects when consuming it.
That said, if you’d like to reduce your intake of added MSG, be sure to check the ingredient panel of packaged foods and condiments. The FDA requires that foods that contain this additive mention it on their packaging.