Toxicological research shows that MSG is harmless, even in large amounts.
MSG, an abbreviation for monosodium glutamate, is a flavor enhancer first introduced into the diet of Asian cuisine from seaweed extract and later refined as a food additive by Kikunae Ikeda in Japan in 1907. Japanese soldiers included MSG in their rations during the World War. II, and this was eventually realized by the US military, who brought it to the United States in the late 1940s, where it became a household word in the 1960s. Monosodium glutamate is a natural amino acid that is not required by humans. body for health, but the glutamic acid from which it is derived is a common salt found in a wide variety of foods and is often listed on labels as hydrolyzed protein, yeast, or soy extract.
Because MSG is so ubiquitous in the diet, both in refined and natural forms, it has been difficult to quantify health concerns about its effects. All forms of hydrolyzed protein, from sodium caseinate to autolyzed yeast, contain some form of glutamic acid from which monosodium glutamate is derived. Large-scale production of sodium salts began in 1956, when the Japanese perfected a fermentation method at the Ajinmoto Company, which holds the MSG patent. With the increasing distribution of the product to thousands of different food product lines, some health side effects began to be attributed to it.
Research done in the late 1960s and early 1970s suggested potential toxicity problems for MSG, especially when incorporated into baby foods at the time. Food regulations in many countries, from the US to Australia and New Zealand, now require all MSG to be labeled as a food additive where it is used. The 2004 toxicology investigation found that even in large amounts, MSG should be considered harmless.
There is some difference of opinion about the effects of the refined form of MSG versus its natural sodium salt equivalents. By refining the manufacturing process, the Ajinomoto Company was able to produce monosodium glutamate, of which 99.6% by volume is made up of the flavor-enhancing compound L-glutamate. However, other unrefined forms of glutamic acids typically have 95% or less of the chemical L-glutamate, so the differences are not too great. Whether or not MSG has harmful long-term health effects, use continues to grow, with more than 1.5 million metric tons of MSG consumed each year.
In addition to being used as a food additive, MSG has been found to be a useful component for plant growth. Glutamic acid derivatives are now incorporated into fertilizers and fungicides sprayed on everything from wine grapes to fruits, nuts, grains and vegetables. In the United States, in 2009, the use of MSG was approved to fumigate all agricultural products.