Is this flavor enhancer actually safe?

Headaches, nausea, weakness, numbness, and chest pain: People who believe they’re sensitive to monosodium glutamate—MSG for short—have reported these and other symptoms for decades. Once a common ingredient, MSG fell out of favor in the 1970s, after people began to worry that it was dangerous. Some activists even call it a toxin that damages brain cells. But if MSG is so hazardous, why is it still lurking in our food?

Like sugar and pepper, MSG is a flavor enhancer. Where sugar adds sweetness and pepper adds bite, MSG provides what food scientists call umami, or the fifth taste (the other four are salty, sweet, bitter and sour). Umami is the rich, savory pungent flavor found in foods such as Parmesan cheese. When it’s present naturally, the umami flavor comes from glutamic acid, one of the molecules that make up protein. Glutamic acid is naturally found in our own bodies and in many healthy foods, such as tomatoes, chicken, and milk. Neither glutamic acid nor MSG is related to gluten.

MSG is basically the man-made form of glutamic acid: In 1908, a Tokyo Imperial University professor Kikunae Ikeda, ScD, isolated and patented the component that made his seaweed broth so tasty. MSG went into production as a flavoring soon after. 

This is where things start to conflict. Research has been done on MSG’s effect on the human body, but so far, studies haven’t been able to consistently replicate the symptoms reported by people who claim to be sensitive to it. “If you look at the scientific research that has been done, the results are confusing and conflicting. Is easy for either side of the MSG story to cherry-pick research to support their position,” says Melanie Warner, author of Pandora’s Lunchbox: How Processed Food Took Over the American Meal. In the 1990s, the US Food and Drug Administration commissioned a report by an independent scientific group that concluded that MSG isn’t harmful in the small amounts that we eat. The FDA classifies it as “generally recognized as safe.” 

To Warner, though, MSG is problematic because it’s an example of “disassembling food into molecular parts. When glutamate is found naturally in foods, it’s bound together in a protein molecule. It’s very different when you cleave that apart.” 

If you believe you’re sensitive to MSG, the best you can do is read food labels carefully. Since 1998, the FDA has required that MSG be specifically called out on the label of any packaged food that includes it and can’t be listed under the generic catchall “spices and flavorings.” But also look for “autolyzed yeast,” “hydrolyzed yeast,” “yeast extract,” “soy extracts,” “hydrolyzed vegetable protein” and “protein isolate.” Although these ingredients aren't MSG, they do naturally contain glutamate.  The FDA doesn't require food companies to tell you that.


  1. Melanie Warner
  2. US Food and Drug Administration