Is It Safe to Consume MSG?
Monosodium Glutamate (MSG) is a popular flavor additive primarily found in Chinese cuisine, but can also be found in tomatoes, meats, and certain cheeses. MSG can often lead to its consumers feeling ill and experience symptoms such as headache, sweating, facial pressure, chest pain, and nausea. While this popular additive has been used widely for a great amount of time, there is still some uncertainty as to whether MSG is safe.
MSG was deemed by The Food and Drug Administration to be generally recognized as safe, but this still doesn’t provide a solid answer as to whether it should be continued to be added to our foods. The danger behind MSG lies in the fact that glutamate is an excitatory neurotransmitter. Glutamate is one of the 20 essential amino acids that is found in our bodies and in many different types of food. When neurons secrete an excessive amount of an excitatory neurotransmitter, such as glutamate, excitotoxicity may occur and subsequently, the death of multiple neurons. Excitotoxicity may result in epilepsy and seizures, which will cause neurons to be excited to a deadly extent.
The blood brain barrier is an important structure in our central nervous system, as it is a very selective barrier and prevents toxins and pathogens from entering the brain’s circulation. The blood brain barrier is not fully developed at birth, and may take years for the development of the barrier to reach completion. Therefore, infants are more susceptible to toxins which can easily enter the brain’s circulation without a barrier. Since adults have a fully formed blood brain barrier, is it safe for us to consume MSG?
MSG was first produced in the form of a powder by Japanese chemist Kikunae Ikeda in 1908. Soon afterwards, Chinese immigrants introduced MSG to the United States and used it as a flavor enhancer for their dishes. The controversy revolving around MSG first took flight when a physician named Robert Ho Man Kwok sent a letter to the New England Journal of Medicine (NEJM) in 1968. This letter described the symptoms he felt after eating food from a Chinese restaurant, which included “numbness in the back of the neck, gradually radiating to both arms and the back, general weakness, and palpitation.” (Blanding) The letter was published by the NEJM and was titled the “Chinese-Restaurant Syndrome”. Subsequently, lots of research was conducted on the effects of MSG to determine whether the described detrimental effects are universal. For example, a study conducted by neuroscientist John Olney in 1969 found brain lesions and impaired development in mice that were directly injected with MSG. These findings, along with the letter published by NEJM, tainted the reputation of MSG.
There have been numerous attempts to debunk the theory that MSG is bad for you. For example, Olney’s study is flawed as he injected MSG directly under the skin of the mice, even though glutamate is metabolized by the small intestine. Professor John Fernstrom, a professor at the University of Pittsburgh School of Medicine, thus claims that Olney’s study alongside other studies that have observed brain damage after injecting MSG are misleading, as humans digest MSG instead of injecting it. Other studies involving placebos have shown that MSG does not cause adverse effects to everyone that consumes it. The most leading conclusion is that some people may have adverse reactions to Chinese food due to the other plant-based spices that some dishes may contain.
The reputation that MSG was given can be largely attributed to prejudice against Asian cuisine and the connotation of such foods being “unclean”. The long-lasting effects of this letter may have fueled consumer’s biases towards Chinese or other Asian cuisines, despite the numerous studies conducted to have found no correlation between MSG and adverse side effects. The International Food Information Council found that 4 out of 10 consumers in the United States are actively avoiding MSG 50 years later after the letter was published. As with other products, MSG should be consumed in moderation by people of any age. In 1991, the European Communities Scientific Committee for Food declared that infants can metabolize glutamate as efficiently as adults, and will metabolize MSG in the same way they metabolize naturally-occurring glutamate.
References:
Blanding, Michael. “The Strange Case of Dr. Ho Man Kwok.” Colgate Magazine, Colgate Magazine, 2 June 2019, news.colgate.edu/magazine/2019/02/06/the-strange-case-of-dr-ho-man-kwok/.
Dewey, Caitlin. “Why Americans Still Avoid MSG, Even Though Its 'Health Effects' Have Been Debunked.” The Washington Post, WP Company, 20 Mar. 2018, www.washingtonpost.com/news/wonk/wp/2018/03/20/why-americans-still-avoid-msg-even-though-its-health-effects-have-been-debunked/.
“MSG Use by Children and Pregnant Women.” International Glutamate Information Service, International Glutamate Information Service, 19 Feb. 2018, glutamate.org/safety/msg-use-by-children-and-pregnant-women/.
Olney, J W. “Brain Lesions, Obesity, and Other Disturbances in Mice Treated with Monosodium Glutamate.” PubMed.gov, U.S. National Library of Medicine, 9 May 1969, pubmed.ncbi.nlm.nih.gov/5778021/.
“Questions and Answers on Monosodium Glutamate (MSG).” U.S. Food and Drug Administration, FDA, 2012, www.fda.gov/food/food-additives-petitions/questions-and-answers-monosodium-glutamate-msg.
Tu, Chau. “Is MSG Bad For Your Health?” Science Friday, Science Friday, 2 Oct. 2014, www.sciencefriday.com/articles/is-msg-bad-for-your-health/.
Zeratsky, Katherine. “How Does Your Body React to MSG?” Mayo Clinic, Mayo Foundation for Medical Education and Research, 3 Apr. 2020, www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/monosodium-glutamate/faq-20058196.
