Monosodium glutamate
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| Dubious diets |
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Monosodium glutamate, more popularly known as "MSG," is a widely-used flavor additive known for its contribution to the fundamental flavor known as umami. It is also purported to be dangerous.
Contents |
[edit] What is MSG
MSG is a salt of glutamic acid, a non-essential amino acid which serves several functions in the body such as neurotransmission (both direct at NMDA receptors and as a precursor to Gamma-Aminobutyric acid (GABA)), protein formation, and metabolism (as part of the citric acid cycle). Its function as a neurotransmitter is essential for both memory and learning.[1] Salts of glutamic acid are referred to as glutamates.
[edit] Dietary sources
MSG and similar sodium salts have been widely used in Asian cuisine for centuries; they develop naturally during the fermentation process of such ingredients as soy sauce, and are also found in certain seaweeds. Now produced chemically or through bacterial fermentation, MSG is one of the most common flavorings used in Chinese, Japanese, and Cantonese cooking. In this capacity, the additive spread into Europe and the United States.
Natural sources of glutamic acid include Marmite, brocolli, wheat, tomatoes, meat, and parmesan cheese.[2] Glutamic acid can also be liberated from vegetable protein via acid-hydrolyzation; hydrolyzed soy protein is often seen on ingredients lists as a food additive because it's shelf stable and contains glutamic acid.
[edit] Health concerns
It became widely believed in the 80s in the United States that MSG posed a health hazard, with a phenomenon called "Chinese Restaurant Syndrome" reportedly resulting from the additive. Evidence for harmful effects from MSG is almost entirely anecdotal. In response, the Federal Food and Drug Administration reviewed the literature and studied the chemical, determining:"There is no evidence in the available information on [substance] that demonstrates a hazard to the public when it is used at levels that are now current and in the manner now practiced. However, it is not possible to determine, without additional data, whether a significant increase in consumption would constitute a dietary hazard."[3]
Though there are no large, reputable studies that show any reaction, and multiple studies demonstrate that there is no discernible syndrome[4][5][6] except for people taking the placebo,[7] public-consumption websites still note that "A small percentage of people may have short-term reactions to MSG."[8] While MSG is no longer considered dangerous by the scientific community, its use in food preparation is seen in culinary circles as "cheating" by improving the flavour of substandard foods in the same way as adding a lot of common salt to fast food is.
One of the most common claims made by woo-peddlers is that MSG will give you seizures or cause brain damage in some way because of the glutamate it contains. This is based on the fact that high levels of glutamate can cause excitotoxicity in the brain. This is true, but the problem with this claim is that glutamate does not cross the blood-brain barrier in healthy humans (though it is a possibility for those with some disease that weakens the barrier).[9] Thus, unless you inject it past the blood-brain barrier directly into the brain, it will have no effect on brain activity.
Despite a widespread belief that MSG can elicit migraine headaches, there is no consistent clinical data to support this claim, nor is there evidence that some individuals are more sensitive to MSG than others. [10][11][12][13] It is more likely that migraines and the other alleged symptoms of "Chinese Food Syndrome" are caused by the high levels of salt, carbohydrates and oils in Americanized Chinese food.[14]
[edit] See also
[edit] External links
- The Notorious MSG’s Unlikely Formula For Success (sadly, not about the Chinese-American hip-hop group "Notorious MSG")
- Skeptical Raptor's Blog: MSG-myth versus science
[edit] Footnotes
- ↑ Glutamate: its role in learning, memory, and the aging brain
- ↑ Monosodium Glutamate, a Safety Assessment
- ↑ http://www.accessdata.fda.gov/scripts/fcn/fcnNavigation.cfm?rpt=scogsListing
- ↑ http://www.ncbi.nlm.nih.gov/pubmed/10736382
- ↑ http://www.sciencedirect.com/science/article/pii/027869159390012N
- ↑ http://www.newscientist.com/article/dn23851-what-if-your-gluten-intolerance-is-all-in-your-head.html?full=true
- ↑ http://www.ncbi.nlm.nih.gov/pubmed/16999713
- ↑ http://www.mayoclinic.com/health/monosodium-glutamate/AN01251
- ↑ Hawkins, RA. The blood-brain barrier and glutamate. Am J Clin Nutr. 2009 Sep;90(3):867S-874S. Epub 2009 Jul 1.
- ↑ Jinap S., Hajeb P. Glutamate. Its applications in food and contribution to health. Appetite. 2010 Aug;55(1):1-10. Epub 2010 May 12.
- ↑ Williams AN, Woessner KM. Monosodium glutamate 'allergy': menace or myth? Clin Exp Allergy. 2009 May;39(5):640-6. Epub 2009 Apr 6.
- ↑ Freeman M. Reconsidering the effects of monosodium glutamate: a literature review. J Am Acad Nurse Pract. 2006 Oct;18(10):482-6.
- ↑ Geha RS, Beiser A, Ren C, Patterson R, Greenberger PA, Grammer LC, Ditto AM, Harris KE, Shaughnessy MA, Yarnold PR, Corren J, Saxon A. Review of alleged reaction to monosodium glutamate and outcome of a multicenter double-blind placebo-controlled study. J Nutr. 2000 Apr;130(4S Suppl):1058S-62S.
- ↑ Skeptical Raptor MSG-myth versus science