People who experience such a reaction may mistake it for an MSG allergy.
But MSG symptom complex is different than an allergy and not yet clearly understood.
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What Is MSG?

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This white, odorless crystalline powder has been used as a flavor enhancer for more than a century.
It’s responsible for the “umami” or savory flavor in many dishes.
It was originally made from boiledseaweed.
Today, it is made by fermenting starch, sugar beets, sugar cane, or molasses.
Likely due to the uncomfortable symptoms people report experiencing after eating foods containing MSG.
It is not a true allergy, but rather a food intolerance.
Studies suggest the food additive may have a connection toheadaches.
Asthma
Research in the 1980s found a suspected link between MSG and asthma.
These results, however, have not been replicated in further studies.
Causes
MSG symptom complex is not very well understood.
The reactions people experience after eating MSG do not involve traditionalallergy pathwaysthat activate an immune response.
Diagnosis
MSG symptom complex is typically diagnosed based on symptoms that appear following MSG consumption.
More serious symptoms may be life-threatening and require immediate medical attention.
U.S Food and Drug Administration.Questions and answers on monosodium glutamate (MSG).
Bawaskar HS, Bawaskar PH, Bawaskar PH.Chinese restaurant syndrome.Indian J Crit Care Med.
2000;130(4S Suppl):1058S-62S.
2013;12(3):106-110.
2013;14:2. doi:10.1186/1129-2377-14-2
- Allen DH, Delohery J, Baker G.Monosodium L-glutamate-induced asthma.J Allergy Clin Immunol.
a systematic review of human studies.J Headache Pain.
2016;17:54. doi:10.1186/s10194-016-0639-4
Mayo Clinic.What is MSG?
Is it bad for you?
Henry-unaeze HN.Update on food safety of monosodium l-glutamate (MSG).Pathophysiology.
2017;24(4):243-249.
2018;17:273-278. doi:10.17179/excli2018-1092
U.S. National Library of Medicine: MedlinePlus.MSG symptom complex.