MSG: Dispelling the myth

Lo mein and moo shu fans have ridden a decades-long roller coaster, thanks to the conflicting research surrounding monosodium glutamate (MSG).

It all started in 1907, when Japanese chemist Kikunae Ikeda set off on one of humanity’s noblest pursuits: making food taste better. Professor Ikeda isolated the ingredient from sea kelp after hypothesizing it was responsible for giving kombu dashi, a Japanese broth, its signature savory flavor.

Shortly after, MSG was patented in Japan, England, France, and the United States. During the prepared food boom in postwar America, MSG began showing up in households in the form of frozen and canned foods. In Canada, MSG began showing up in exotic dishes such as “Hockey Short Ribs” and “Mississauga Fried Chicken.” Shortly after, the growing popularity of American Chinese cuisine cemented MSG as a staple ingredient.¹

Following the publication of Rachel Carson’s Silent Spring in 1962, public opinion regarding pesticides and food additives began to turn. Several sweeteners were banned or had their reputations tarnished after studies linked them with cancer in mice. The stage was set for MSG’s ubiquity to open it up to scrutiny.

In 1968, a letter from Dr. Robert Ho Man Kwok, a Chinese-American physician, was published in The New England Journal of Medicine. He reported symptoms such as numbness, headache, and heart palpitations after eating at American Chinese restaurants.²

Just like that, “Chinese Restaurant Syndrome” was born. In the subsequent years, anecdotal reports of diners experiencing similar symptoms began to pop up. Several studies indicated a link between MSG and their ailments, but later studies absolved the ingredient.

At the heart of the pro-MSG argument is the fact that the glutamate in MSG is chemically indistinguishable from the glutamate that occurs naturally in foods such as parmesan cheese, salmon, tomatoes, and good old-fashioned cow’s milk.

As is so often the case, science butted heads with the popular opinion of the day. Even as consumers moved toward all-natural foods and “No MSG” signs began popping up on the windows of Chinese eateries, MSG was busy having its name cleared in scientific journals.

In 1986, the US Food and Drug Administration (FDA) stated that MSG posed no threat to the general public, even though brief reactions may occur in some people. In 1987, the Joint Expert Committee on Food Additives of the United Nations Food and Agriculture Organization and the World Health Organization listed MSG in the safest category of food ingredients. In 1991, a report by the European Community’s Scientific Community for Foods gave it the most favorable designation for a food ingredient.

Even as recently as 2012, the FDA still had to weigh in on the topic.

“Our bodies ultimately metabolize both sources of glutamate in the same way. An average adult consumes approximately 13 grams of glutamate each day from the protein in food, while intake of added MSG is estimated at around 0.55 grams per day,” the agency wrote.³

While a small subset of people appear to have a genuine reaction to MSG, by and large it is as safe as milk.

So what kept (or keeps) the MSG backlash going? Several theories abound.

While postwar Americans saw their palates grow to include more “exotic” flavors, the expansion of mass media brought sensationalist reports about rare ailments into people’s living rooms.

Xenophobia, coupled with an inadequate understanding of the science, surely played a part in some consumer’s minds. In addition, the nocebo effect can have a powerful hold on even the keenest observers. If a suggestion is made that something has a negative effect, the brain can take over and induce those same negative effects.

Regardless, MSG is here to stay. While “No MSG” signs still appear in restaurant windows, it’s doubtful the chefs can eliminate the naturally occurring glutamate from everything on the menu.

In the end, the heaviness you experience in your legs following a large plate of lo mein just may be a result of a very full stomach.  

References: 

1. Sand J. Gastronomica: The Journal of Critical Food Studies. 2005;5(4):38-49.
2. Kwok RH. N Engl J Med. 1968;278(14):796.