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The MSG Hate Train

by Brenda Mao

MSG is one of the most common food additives in cuisine, often associated with Chinese takeout. It has been used for over a century, but due to faulty research and racist fearmongering, MSG has a terrible reputation in the public eye. 

MSG stands for monosodium glutamate. It’s made from an amino acid called glutamic acid (a nonessential amino acid), water, and sodium. MSG is produced by fermenting carb sources like corn, sugar cane, tapioca, etc. It appears as a white, odorless, crystalline powder. In the cooking industry, it is known as E621. 

It doesn’t have a specific flavor on its own; instead, MSG enhances the natural flavors of other foods. As such, it’s often added to restaurant foods, canned vegetables, soups, deli meats, and many snacks. MSG adds umami, which is considered the fifth flavor, along with sweet, salty, bitter, and sour. Umami roughly translates to savory, and increases saliva production – literally, it makes your mouth water. MSG has about one-third the amount of sodium as standard table salt, making it a popular substitute. 

Additionally, MSG occurs naturally in many foods, including corn, green peas, mushrooms, tomatoes, grapes, and some cheeses. So why is it so heavily stigmatized in popular culture?

In 1968, a Chinese-American doctor named Robert Ho Man Kwok wrote a letter to the New England Journal of Medicine explaining that he fell ill after eating Chinese food. He believed his symptoms could have resulted from consuming cooking wine, sodium, or MSG. This letter sparked a ton of misinformation about MSG, only further amplified by the racial biases against Asian people at the time. Dr. Kwok reported that he had headaches, flushing, a burning or tingling sensation, chest pain, nausea, and overall weakness. These symptoms were dubbed the “Chinese restaurant syndrome,” which was later named the “MSG symptom complex.”

From then on, there was a socially ingrained bias against MSG. People would assume they were having a reaction to MSG if they felt sick after eating, especially after eating Chinese food. In reality, all foods that are highly processed can cause similar symptoms due to high sodium content and other ingredients. There was such heavy backlash against MSG that restaurants and food labels would start advertising that they’d cut it out entirely. It was called a “toxic additive,” and studies at the time backed up that belief. 

However, during these old studies, participants were told whether or not they would be consuming MSG. In a sort of nocebo effect (think the opposite of the placebo effect), people would automatically feel like they were experiencing sickness. During later studies, researchers found the vast majority of people don’t have any reaction when they don’t know they’re consuming MSG. Later research has also shown there is no clear link between MSG and the reported symptoms. Some people have a sensitivity to MSG, causing them to experience MSG symptom complex. This is estimated to affect less than 1% of the general population. Even then, symptoms are generally very mild and will disappear in around an hour. The FDA says these side effects are most likely to occur after an MSG-sensitive person consumes more than 3 grams of MSG. This is extremely unlikely, as most foods contain less than 0.5 grams of MSG.

A common complaint about MSG is that it causes obesity. This is untrue: MSG has not been shown to affect fat cells, leptin receptors, or other parts of the body associated with weight gain. In the past, MSG was associated with an increased risk of metabolic disorders because of animal studies that showed possible insulin resistance, high blood sugar levels, and diabetes. However, this research used imprecise methods for administering MSG, such as using injections instead of oral doses.

 MSG was also reported to disrupt the signaling effect of the hormone leptin, which is in charge of telling your body that you’re full. As such, people thought that it would cause you to overeat. Some studies have shown that it may actually reduce appetite, while others say that since it enhances flavor, people are inclined to eat more of it. 

Additionally, many believed that MSG can cause a deterioration in brain function. Glutamate, the salt form of glutamic acid, plays important roles in brain function, like serving as a neurotransmitter. Some research has claimed that MSG can lead to brain toxicity by causing excessive glutamate levels, thereby overstimulating nerve cells and causing cell death. Dietary glutamate likely has little to no effect on your brain, as almost none of it passes into the blood or crosses the brain barrier. In fact, once ingested, MSG is completely metabolized in the gut, where it either serves as an energy source, is converted to other amino acids, or is used in the production of various bioactive compounds.

Multiple national and international organizations, like the World Health Organization, the United Nations Food and Agriculture Organization, etc. all agree that MSG is not a health hazard. The FDA still requires companies to list MSG on food labels, so if you want to avoid it, look out for hydrolyzed vegetable protein, autolyzed yeast, hydrolyzed yeast, yeast extract, soy extracts, and protein isolate.

The US has a longstanding history of viewing Asian cuisine as less healthy and dangerous. People were all too eager to hate Asian restaurants and foods as soon as a little evidence emerged. In recent times, people are more willing to accept MSG as a harmless additive. 

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