As discussed in last week’s article, some creative scientists are examining the changes in Hawaiian seafood menus over time for useful data about fishery abundance. If researchers were to study another set of menus, those of Chinese restaurants in the United States, they would find a similarly interesting trend: from the early 1970s onward, many menus began to advertise the absence of monosodium glutamate, or MSG, in their cuisine. The U.S. Food and Drug Administration, however, has labeled MSG as a “generally recognized as safe” food ingredient since 1959. A sudden change in public perception led to these changes, but the roots of that perception are surprisingly obscure.
Although MSG was only formally discovered in the early 20th century by Japanese chemist Kikunae Ikeda, the compound from which it is derived, glutamic acid, is one of the 20 amino acids necessary for proteins (and therefore life itself). The body recognizes the importance of glutamic acid through the sense of taste in foods like asparagus, tomatoes, cheese and meat. Just as the tongue’s taste buds detect sodium chloride as salty, sucrose as sweet, or quinine as bitter, they register glutamic acid as its own unique taste, designated by Ikeda as “umami,” a Japanese word for “delicious” or “yummy” that is often translated as “savory.” MSG is simply glutamic acid that has been stabilized through the addition of sodium; for comparison, MSG contains one-third the amount of sodium per unit volume as table salt.
Asian cooking traditionally derived umami flavor from ingredients such as seaweed (from which Ikeda first isolated glutamic acid) and dried tuna, but by the 1950s, purified MSG was available to the United States as the seasoning Ac’cent. Restauranteurs and food processors were quick to adopt the ingredient as an inexpensive way to bolster the flavor of their products. No concerns were raised by the substance’s inclusion until 1968, when a Chinese-American doctor named Robert Ho Man Kwok reported feeling a number of ill effects after eating at Chinese restaurants in the United States.
As BuzzFeed’s John Mahoney outlines, Dr. Kwok hypothesized in the New England Journal of Medicine that his symptoms may have been “caused by the monosodium glutamate seasoning used to a great extent for seasoning in Chinese restaurants,” and after the New York Times covered the story, a flurry of experiments were conducted to confirm his suspicions. Many of these studies did report an association between high doses of MSG and symptoms such as headaches and flushing, but they lacked the proper scientific rigor of double-blind design (in which both the experimenter and subject do not know which treatment is being administered) or placebo controls.
Better designed experiments over the following decades failed to confirm the results of earlier research, and a comprehensive review by the Federation of American Societies for Experimental Biology concluded that were was no association between MSG and short- or long-term health issues in humans. Despite this research, a number of groups have continued to advocate about the perceived dangers of the compound, and MSG has been absent from baby food since 1969. Yet as the scientific consensus stands, one should feel no fear in enjoying a plate of egg foo young from a Chinese restaurant, even if the menu is silent about the presence of MSG.