Updated at 1:45 p.m. ET on May 17, 2023
In March, the World Health Organization issued a dire warning that was also completely obvious: Nearly everyone on the planet consumes too much salt. And not just a sprinkle too much; on average, people consume more than double what is advisable every single day, raising the risk of common diseases such as heart attack and stroke. If governments intervene in such profligate salt intake, the WHO urged, they could save the lives of 7 million people by 2030.
Such warnings about salt are so ubiquitous that they are easy to tune out. In the United States, salt intake has been a public-health issue for more than half a century; since then, the initiatives launched to combat it have been deemed by health officials as “too numerous to describe,” but little has changed in terms of policy or appetite. The main reason salt has remained a problem is that it’s a major part of all processed food—and, well, it makes everything delicious. Persuading Americans to reduce their consumption would require a convincing dupe—something that would cut down on unhealthy sodium without making food any less tasty.
No perfect dupe exists. But the next best thing could be … MSG. Seriously. Last month, the FDA proposed reducing sodium in certain foods using salt substitutes. One candidate that has research behind it is monosodium glutamate, the white crystalline powder that has long been maligned in the West as an unhealthy food additive. A common seasoning in some Asian cuisines, MSG was linked in the late 1960s to ailments—headaches, numbness, dizziness, heart palpitations—that became known as Chinese Restaurant Syndrome. The health concerns around MSG have since been debunked, and the FDA considers it safe to eat. But it still has a bad rap: Many products are still proudly advertised as MSG free. Now the chemical may soon get its revenge. Given the chance to replace salt in some of our food, it could eventually come to represent something wholesome—perhaps even something close to healthy.
The concerns with MSG originated in 1968, when a Chinese American physician, writing in The New England Journal of Medicine, described feeling generally ill after eating Chinese food, which he suggested could be because of MSG. Other researchers quickly produced studies that seemed to substantiate this claim, and MSG became a public-health villain. In the ’70s, the Chicago Tribune ran the headline “Chinese Food Make You Crazy? MSG Is No. 1 Suspect.” All the attention “renewed medical legitimacy [for] a number of long-held assumptions about the strangely ‘exotic’, ‘bizarre’ and ‘excessive’ practices associated with Chinese culture,” the historian Ian Mosby wrote in 2009. That’s not to say that all symptoms associated with MSG are bunk; people can be sensitive to MSG—like any food—and may experience broad symptoms such as headaches after eating it, Amanda Li, a dietary nutritionist at the University of Washington, told me. But “research has shown no clear evidence linking MSG consumption to any serious potential adverse reactions,” she said.
On the whole, MSG does seem better than salt itself, considering that excessive salt consumption poses so many chronic health risks. A relatively small amount of MSG could be used to rescue flavor in reduced-salt products without endangering health. This is possible partly because of MSG’s molecular makeup. It satisfies the need for salt to a certain extent because it contains sodium (it’s right there in the name, after all)—but just a third of the amount, by weight, that salt does. The rest of the molecule is made of the amino acid L-glutamate, which registers as the savory, “brothy” flavor known as umami.
MSG isn’t a one-to-one replacement for salt, but that’s what makes it such a promising alternative. It is a general flavor enhancer, meaning that it can amplify the perception of salt and other flavors that are already in a dish, as well as add an umami element, Soo-Yeun Lee, a sensory scientist and the director of Washington State University’s School of Food Science, told me. One secret to this effect is that unlike salt, which imparts a blast of flavor and then quickly dissipates, MSG stays on the tongue long after food is swallowed, producing a lasting savory sensation, Lee said. It may amplify saltiness by increasing salivation, letting sodium molecules wash over the tongue more freely, Aubrey Dunteman, a food scientist at the University of Illinois at Urbana-Champaign, told me.
All of this gives MSG the potential to play into a salt-reduction strategy. A 2019 study in the journal Nutrients found that substituting MSG (or other similar but more obscure chemicals) for some of the salt in certain foods could have major impacts: Adults who eat cured meats could cut 40 percent of their intake; cheese eaters, 45 percent. Another study from researchers in Japan found that incorporating MSG and other umami substances into common Japanese condiments, such as soy sauce, seasoning salt, and miso paste, could cut salt intake by up to 22.3 percent. Doing the same in curry-chicken and chili-chicken soups, Malaysian scientists found, could be used to reduce the recipes’ salt content by 32.5 percent.
Take those findings with a grain of, uh, MSG. Recent studies have uniformly found that MSG is a safe, promising salt replacement, but many, including both the Nutrients study and the Japanese one, were funded at least in part by Ajinomoto Co.—the company that introduced the first commercial form of the substance—or the International Glutamate Technical Committee, a trade group. Lee and Dunteman have also received funding from Ajinomoto for some of their MSG work, including a study showing that the substance could improve the flavor of reduced-sodium bread. Lee said she aimed to show that MSG substitution for salt is “feasible, so if any food companies want to take that up and try it on their own systems,” they have a basis for doing so. Her goal, she added, “is not to sell bread with MSG.” (The paper, along with the two others mentioned that received industry funding, were independently peer-reviewed.)
Clearly, more independent research is needed, but food companies have plenty of incentive to help find a better alternative to salt. More than 70 percent of Americans’ salt consumption comes from processed and manufactured food, and if the FDA decides to crack down on salt intake, its policies will largely target the food industry, Lee said. Already, some manufacturers of canned soup and fish are experimenting with salt substitutes.
Deploying MSG in a sweeping sodium-reduction campaign would not be straightforward. MSG is more expensive than salt, Dunteman noted. More crucially, in many foods, salt provides more than flavor; it can also act as a preservative and regulate texture by, say, adding juiciness to lean meat or stabilizing leavened dough. In their study on bread, Lee and Dunteman found that removing too much salt reduced chewiness and firmness, even when MSG made up for taste. Among common processed foods, bread is a prime target for future MSG research, because it is the biggest contributor to U.S. sodium intake—not only because of its salt content but also because of the sheer amount of it that Americans consume. When MSG is used instead of salt to enhance flavor, “foods can taste just as delicious but without affecting hypertension,” Katherine Burt, a professor of health promotion and nutrition sciences at Lehman College, whose writing on MSG was not industry funded, told me. It’s “a great way to make foods exciting and healthy.”
MSG can also be used to deliberately reduce salt intake at home. Adding a new ingredient to a home pantry can be daunting, but consider that MSG is already in most kitchens, occurring naturally in umami-rich items such as Parmesan cheese and mushrooms and added to processed foods such as Campbell’s Soup and Doritos. These days, it’s easy enough to find it online or in stores, sold in shakers or packets, much like salt. Li recommends that the MSG-curious start seasoning their food with a 50–50 mixture of MSG and table salt. When eating processed foods, choose low-sodium versions of products (not “reduced sodium” goods, which may not actually have low levels of salt). They’ll likely taste terrible, so add MSG in increments until they taste good, Lee said.
We still have much to learn about MSG as a salt substitute, but the biggest challenge to it taking off is cultural, not scientific. To a certain degree, tastes are changing: Celebrity chefs such as David Chang champion it, and one highly acclaimed New York restaurant now serves an MSG martini. But the perception that MSG is unhealthy still persists, despite evidence to the contrary. Words such as “sneaky,” “disguised,” and “nasty” are still used to describe it, and grocery stores such as Whole Foods and Trader Joe’s make a point of mentioning that their foods have no MSG. Nevertheless, as long as old misconceptions about MSG persist, they will continue to hamper the potential for a better salt substitute. America’s aversion toward MSG may be intended to promote better health, but at this point, it might just be doing precisely the opposite.
This story originally stated that the New England Journal of Medicine letter about MSG was a hoax. This was once believed but has since been disproved.