The Truth Behind Monosodium Glutamate (MSG)

Monosodium glutamate is the sodium salt of glutamic acid*, a naturally occurring dispensable (nonessential) amino acid found both in animal-based and plant-based foods. Indeed, a sodium ion combined with glutamic acid leads to the formation of monosodium glutamate. The ionized form of glutamic acid, glutamate, is released when proteins are hydrolyzed while cooking. *The protonated form of glutamate, which is a fancy way of saying that it has extra hydrogen atoms!

Why is monosodium glutamate such a controversial topic?

Well, certainly because glutamate is highly distributed in brain tissue, where it is present in higher concentration than any other amino acid. The contribution of glutamate to synaptic transmission, plasticity and development is well established. It has also been noted that glutamate receptors are involved in excitatory neurotransmission, memory acquisition, learning as well as in some neurodegenerative disorders.

MSG is not regulated as a food additive, but is considered a flavor enhancing ingredient used to enhance the natural flavor of various foods imparting a unique taste known as “umami”, the fifth basic taste. Amount of MSG added should be small and consistent with Good Manufacturing Practice (GMP). In general, the use of MSG is not considered a health hazard to consumers. However, some may exhibit allergic-type reactions or hypersensitivity to it. Symptoms may include a burning sensation, facial pressure, headache, nausea and chest pains. Therefore, people sensitive to MSG are advised to avoid the use of this substance. In the same way, foods that are naturally high sources of free glutamate may also be of concern to sensitive individuals. Food sources include miso paste, soy sauce, walnuts, fish sauce, seaweed, dried shiitake mushrooms, parmesan cheese, etc.

Finally, MSG is not “dangerous”, but it is advised to limit its excessive use and since it does not add a characteristic flavor on its own, adding exaggerated amounts of it will not by itself improve the palatability of your meal. Therefore, try to work on your spices’ combinations, cooking methods, etc. instead of relying solely on foods high in glutamate to compensate for your maybe not-so-on-point culinary skills!

References

Fonnum, F. (1984). Glutamate: a neurotransmitter in mammalian brain. Journal of neurochemistry, 42(1), 1-11.

Health Canada. (2008). Monosodium glutamate (MSG) - Questions and Answers. Retrieved September 16th, 2020 from https://www.canada.ca/fr/sante-canada/services/aliments-nutrition/salubrite-aliments/additifs-alimentaires/foire-questions-glutamate-monosodique.html

International Glutamate Information Service. (2020). Foods Rich in Umami Taste. Retrieved September 16th, 2020 from https://glutamate.org/basic/foods-rich-umami-taste-natural-msg/

Nakanishi, S. (1992). Molecular diversity of glutamate receptors and implications for brain function. Science, 258(5082), 597-603.

Riedel, G., Platt, B., & Micheau, J. (2003). Glutamate receptor function in learning and memory. Behavioural brain research, 140(1-2), 1-47.

The Glutamate Association. (2020). Glutamate in Food. Retrieved September 16th, 2020 from https://msgfacts.com/glutamate-in-food/