The signs began to slowly crop up in the windows of your favorite Asian food restaurant: No MSG. The labels spread from windows to food labels, food companies making sure you knew they didn’t use MSG. But beyond allegedly being bad for you, common knowledge is lacking on what the food additive actually is and why you should avoid MSG. 

MSG, short for monosodium glutamate, is a white, odorless food additive made from fermenting carbohydrates like sugar cane, molasses, and sugar beets. MSG can also be used as a salt substitute since the flavor enhancer can bring a unique, meaty flavor to dishes that the U.S. Food and Drug Administration (FDA) has determined is “generally recognized as safe.” 

The idea of eating MSG, especially from Chinese restaurants, can cause what’s known as Chinese Restaurant Syndrome. The term became so ubiquitous that Merriam-Webster even added it to their dictionary in 1993, the definition warning that eating Chinese food can cause a variety of bad physical symptoms. 

‘Chinese Restaurant Syndrome’ Started as a Bet

The first reports of issues with MSG came in the late 1960s. In 1968, two doctors made a bet for $10 that orthopedic surgery wasn’t prestigious enough of a specialty to land the surgeon on the pages of a prestigious medical journal. Using their weekly food and beer binges at a local Chinese restaurant as his inspiration, the surgeon wrote a letter to the New England Journal of Medicine (NEJM) about what he called “Chinese Restaurant Syndrome.” 

The surgeon, Dr. Howard Steel, told Colgate Magazine that he thought he did everything he could to make the letter sound fake. Not only did he sign the letter with a name he thought sounded very made up — Dr. Ho Man Kwok — but the institution he said he was affiliated with, National Biomedical Research Foundation, never existed. He was not expecting the letter to be taken seriously, let alone published.

Nevertheless, within six weeks of the letter’s publication, the NEJM published an additional 10 letters from seven doctors, all claiming to experience the same issues they read about. 

What Is MSG?

According to the FDA, MSG is also a naturally occurring additive in glutamate-based foods like tomatoes, mushrooms, and cheeses. MSG is also found in “hydrolyzed vegetable protein, autolyzed yeast, yeast extract, soy extracts, and protein isolate.”

 Since MSG is naturally occurring, Consumer Reports adds foods aren’t required to be labeled with MSG. However, companies cannot label foods as “No MSG” or “No added MSG” if they have natural or artificial MSG. 

Despite its natural origins, MSG is often anecdotally linked to symptoms such as headaches, chest pain, sweating, and nausea, among other symptoms. However, there is a clear lack of evidence to support that MSG is the food ingredient causing these issues. 

The FDA does report receiving claims of adverse symptoms, though no study has yet to prove a direct link between MSG and the symptoms. This includes people who claim to have MSG sensitivity, as studies have been unable to trigger consistent negative reactions.