It’s commonly accepted as fact that MSG, a.k.a. monosodium glutamate, is something we should avoid, the culprit behind the so-called “Chinese Restaurant Syndrome” and contributor to myriad health problems. But is there any substance behind MSG’s bad reputation?
What is MSG? In 1908, Japanese chemistry professor Kikunae Ikeda noticed that certain foods had a savory taste—including Parmesan cheese, ripe tomatoes, dry-aged beef, and kombu dashi, a broth made from dried kelp that’s essential to Japanese cooking. Ikeda named that flavor “umami” and started investigating what caused it. He cooked dashi down until it formed crystals, which turned out to be made of sea salt and glutamate. In other words, monosodium glutamate.
Glutamate is one of 20 amino acids—the building blocks of protein—but it’s also an important neurotransmitter. Your body synthesizes about 50 grams of glutamate each day, but because it’s so vital to us, glutamate is also found in human breast milk and makes up 8–10% of most protein foods. The cells lining your intestine use almost all of the glutamate you get from food to fuel their constant regeneration.
“Chinese Restaurant Syndrome.” In 1968, the New England Journal of Medicine published a letter titled “Chinese Restaurant Syndrome.” The author was a doctor who had experienced a number of symptoms—including numbness in the back of the neck, weakness and heart palpitations—after eating at a Chinese restaurant. He speculated about possible culprits—soy sauce, cooking wine, MSG, or mild dehydration caused by excessive salt.
What followed was a number of research studies that claimed to confirm that MSG caused symptoms. However, these studies had no relation to how people actually consume MSG. For example, researchers in one 1969 study injected participants with MSG or fed them large doses on an empty stomach. In numerous animal studies, researchers repeatedly injected young rodents with doses of MSG equivalent to injecting a 150-pound person with 136-545 grams of MSG. For perspective, in a single day the average American ingests one-half gram of MSG—far less than the average 4.6 grams consumed in Taiwan—along with 13 grams of naturally occurring glutamate from food. In spite of that, these studies were presented as “proof” that MSG causes headaches, or worse, and many researchers continue to cite these studies and conduct similar research.
At the 2018 World Umami Forum, Lisa Watson, MS, a science advisor for The Glutamate Association, pointed out that our bodies don’t distinguish between glutamate that’s naturally present in food and glutamate that’s been added to food. “We get far more glutamate from our food than from MSG, and do we say that the Parmesan cheese on our pasta gives us a headache?” Accordingly, in 2018, the International Headache Society removed “MSG-induced headache” from its Classification of Headache Disorders.
FDA involvement. In the mid-1990s, after years of receiving reports of MSG-related symptoms such as headache and nausea, yet being unable to confirm that MSG was the true culprit, the Food and Drug Administration (FDA) took further steps. They asked the independent scientific group Federation of American Societies for Experimental Biology (FASEB) to examine MSG’s safety.
FASEB found that some sensitive individuals who consume three grams or more of MSG without food may experience short-term, temporary, and generally mild symptoms—such as headache, numbness, flushing, tingling, palpitations, and drowsiness. However, the report said consuming more than three grams of MSG without food at one time is unlikely, because a typical serving of a food with added MSG contains less than half of a gram. The conclusion? MSG is safe.
At the World Umami Forum, registered dietitian Mary Lee Chin, MS, RD, who has used MSG her entire life, pointed to MSG’s safety record but acknowledged that the small number of people who are sensitive to MSG should simply avoid it. “If you eat MSG or any other food or food ingredient that causes (contributes to) an adverse effect then eliminate it from your diet,” she says.
Guilt by association? Since the 1960s, the main source of MSG in America has been processed food, which is ironic, because MSG’s original purpose was to make healthy food taste better. MSG boosts a food’s flavor without hiding or overwhelming it. For example, a simple vegetable broth lightly seasoned with salt will taste a little bland. If some of the same broth is seasoned with MSG, the flavors of the vegetables become more pronounced, and the broth develops a satisfying mouthfeel—all without increasing the total amount of sodium.
In 2010, the Institute of Medicine said that MSG could be an effective way to reduce sodium. Because MSG is 12% sodium and table salt is 39% sodium, cutting salt by one-third and replacing it with MSG reduces sodium by 25% without compromising taste. Additionally, new research suggests that MSG enhances food satisfaction in a way that helps improve food intake in people who struggle to eat enough without encouraging overeating in general. These two examples show how MSG might be more than just safe—it might even be beneficial.
—Carrie Dennett, MPH, RDN