As a college student in New York City, I marveled that the city let me eat poached eggs with halloumi cheese and Moroccan spiced pita for breakfast, a spicy-sweet minced meat salad from northern Thailand for lunch, and Singaporean nasi lemak for dinner. My requisites were pretty straightforward: delicious, cheap and served in bulk. But if I was eating Chinese, I added one more: no MSG.

Like many people, I thought MSG — monosodium glutamate, a chemical compound used to enhance the flavor of food — was bad for me, and I was sure I felt terrible every time I ate it. After all, I was sluggish and had headaches and achy limbs whenever I ate a big meal in Chinatown. Now I know that the recurring headaches that plague me have little to do with what I eat. But at the time, avoiding those three letters brought me comfort and let me think I’d be eating some sort of sacredly pure meal made with food, not chemicals. Oh, how young and foolish I was.

That MSG isn’t the poison we’ve made it out to be has been well-established. News stories are written regularly about the lack of evidence tying MSG to negative health effects. (Read here and here, for example. Or here, here, here, here and here.) Still, Yelp reviews of Chinese restaurants tell tales of racing hearts, sleepless nights and tingling limbs from dishes “laden with MSG.” Even when the science is clear, it takes a lot to overwrite a stigma, especially when that stigma is about more than just food.

Since its discovery in the early 1900s, MSG has been synonymous with delicious. When added to foods, it increases umami, which has been considered the fifth taste since the early 2000s (alongside sweet, sour, salty and bitter ) and varyingly translates from Japanese as “tasty,” “scrumptiousness,” “deliciousness” or “savory.” Umami is the full-bodied, savory taste found in a wide variety of foods, such as parmesan and mushrooms, as well as in most meat. MSG is its crystallized manifestation.

Kikunae Ikeda, a Japanese chemist, discovered the compound in 1907 while investigating a common quality he’d noticed in foods like asparagus, tomatoes and the soup broth his wife made with seaweed. He determined that glutamate, the ionic form of glutamic acid, was responsible for umami. He then figured out how to synthesize the molecule by extracting glutamate from seaweed and mixing it with water and table salt to stabilize the compound. Ikeda patented the finished product, and it became one of Japanese food science’s greatest commercial successes. Today, the crystallized seasoning, frequently made from beets and corn, is known as MSG in the U.S. but is often called by the name Ikeda first gave it — “Aji no Moto,” or Essence of Taste — in other parts of the world.

The fine, white powder was first sold in slender bottles meant to attract bourgeois housewives who were embracing science in the kitchen because it suggested hygiene and modernity, according to research by Jordan Sand, a professor of Japanese history at Georgetown University. In China, it was touted to Buddhists, who periodically abstained from eating meat, as a vegetarian way to improve flavor.

By the 1950s, MSG was found in packaged food across the U.S., from snacks to baby food. (Sand said in his 2005 paper that his 1953 edition of “The Joy of Cooking” referred to monosodium glutamate as “the mysterious ‘white powder’ of the Orient … ‘m.s.g.,’ as it is nicknamed by its devotees.”) Soon, though, MSG’s chemical nature would turn against it. After the publication of Rachel Carson’s “Silent Spring” and federal bans on sweeteners that the Food and Drug Administration deemed carcinogenic, consumers began to worry about chemical additives in their food. In 1968, the New England Journal of Medicine published a letter from a doctor complaining about radiating pain in his arms, weakness and heart palpitations after eating at Chinese restaurants. He mused that cooking wine, MSG or excessive salt might be to blame. Reader responses poured in with similar complaints, and scientists jumped to research the phenomenon. “Chinese Restaurant Syndrome” was born.

Early on, researchers reported an association between consuming MSG and the symptoms cited in the New England Journal of Medicine. Inflammatory headlines and book titles followed: “Chinese food make you crazy? MSG is No. 1 Suspect,” wrote the Chicago Tribune, while books titled “Excitotoxins: The Taste That Kills” and “In Bad Taste: The MSG Symptom Complex” prompted FDA reviews and “60 Minutes” investigations, as Alan Levinovitz, a professor of Chinese philosophy at James Madison University, chronicled in a 2015 book about food myths.

But those early studies had essential flaws, including that participants knew whether or not they were consuming MSG. Subsequent research has found that the vast majority of people, even those claiming a sensitivity to MSG, don’t have any reaction when they don’t know they are eating it.

That MSG causes health problems may have thrived on racially charged biases from the outset. Ian Mosby, a food historian, wrote in a 2009 paper titled “‘That Won-Ton Soup Headache’: The Chinese Restaurant Syndrome, MSG and the Making of American Food, 1968-1980” that fear of MSG in Chinese food is part of the U.S.’s long history of viewing the “exotic” cuisine of Asia as dangerous or dirty. As Sand put it: “It was the misfortune of Chinese cooks to be caught with the white powder by their stoves when the once-praised flavor enhancer suddenly became a chemical additive.”

The concern wasn’t just among the public, however. From the late 1960s to early 1980s, “Chinese Restaurant Syndrome” was considered a legitimate ailment by many in the medical establishment, according to Mosby’s research. The same can’t be said today. While nearly all the U.S. research that has suggested MSG is safe has been funded by companies that have a stake in MSG’s success, researchers think the science that underlies them is sound.

Of course, a small subset of people do have negative reactions that are directly due to glutamate, but the science to date shows that is likely to be a rare phenomenon. MSG is still, and has always been, on the FDA’s “generally recognized as safe” food list. Several allergists I reached out to who were once go-to experts on the subject declined to comment, saying that they no longer keep up with the research.

Just because there isn’t a scientific association between a given food and negative health effects doesn’t mean the pain or discomfort experienced by diners is imaginary. People who suffer after eating MSG may be experiencing the nocebo effect, the lesser-known and poorly understood cousin of the placebo effect. The phenomenon is what happens when suggesting that something can cause a negative reaction induces precisely those physical symptoms. When a Chinese restaurant puts “no MSG” on its menu to reassure customers, it furthers the stigma, likely furthering the nocebo effect in the process. As with the placebo effect, the nocebo effect can have very real reactions.

With various chefs speaking publicly about the value of MSG, in addition to the medical establishment, the time may be ripe for the public to follow. But changing minds likely won’t be easy.

As Brendan Nyhan, a Dartmouth professor who has researched how to influence attitudes about vaccines, pointed out to me in an email, it’s hard for people to change their minds about personal health issues because it contradicts what they have perceived to experience in the past. “People who felt bad after eating Chinese food in the past may have blamed MSG … and thus resist information they encounter later about its actual effects,” he said. This may be the result of the availability heuristic, where people make judgments using the easiest information available, rather than looking for alternative explanations.

As my colleague Christie Aschwanden has explained, once we reach false conclusions, our brains prevent us from accepting new information that can correct those mistaken assumptions.

When it comes to MSG, the false connections are fairly innocuous for most people but may still cause unnecessary discomfort for some, either because they are experiencing the nocebo effect or depriving themselves of deliciousness. We all make choices about how we eat; for some people, those decisions are based on supporting local economies, avoiding meat for the humane treatment of animals, or simply wanting to know what goes into their bodies. There’s no right or wrong, but it’s worth understanding the origins of those choices. In the case of MSG, they appear to have been less about science and more about the culture and politics of the day.

Read more: You Can’t Trust What You Read About Nutrition