What Are the Symptoms of MSG Allergy?

MSG Allergies

MSG Allergies
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What Are the Symptoms of MSG Allergy?

MSG, or monosodium glutamate, is a flavor enhancer added to various foods, and also occurs naturally in seaweed. Adverse reactions to food additives like MSG are probably relatively common. However, since many reactions to food additives are not diagnosed are never reported by people, the exact rate of reactions is not known. Various studies estimate that the rate is probably less than 1% of adults, and up to 2% of children.

Reactions to MSG have been called the “Chinese Restaurant Syndrome,” referring to that fact that MSG is commonly found in Asian-style foods. Most people who are affected will experience symptoms shortly after eating foods containing MSG. Typical symptoms include numbness on the back of the neck, shoulders and arms; people can have a sense of generalized weakness, and heart palpitations can occur. Other symptoms include facial pressure, headaches, nausea, chest pain, and drowsiness.

Studies on MSG causing reactions in people have shown inconsistent results. Mild reactions have been proven when MSG was taken in large amounts without food, but no reactions were seen when MSG was given with food (which is the way it normally is eaten). Reactions to MSG are not truly allergic; reactions may be caused by toxicities to the nervous system or even by an irritant effect on the esophagus. While studies have not proven that MSG causes severe allergic reactions (such as anaphylaxis), a person with reactions to MSG should attempt to avoid this food additive and be prepared to treat a severe reaction should one occur.

Testing for MSG Allergy

Unfortunately, there is no test available for MSG allergy -- skin tests and blood tests are not available. However, it is possible to perform an oral challenge to MSG -- but as an allergist, I haven't seen this done recently. 

Treatment of an MSG Allergy

Avoidance of MSG is the mainstay of MSG allergy.

Following a preservative-free diet may be one way of accomplishing this.

Learn more about allergic reactions to food additives and preservatives.

Sources:

1. Wilson BG, Bahna SL. Adverse Reactions of Food Additives. Ann Allergy Asthma Immunol. 2005; 95:499-507.

2. Bush RK, Taylor SL, Hefle SL. Adverse Reactions to Food and Drug Additives. In: Adkinson NF, Yunginger JW, Busse WW, et al, eds. Middleton’s Allergy Principles and Practice. 6th edition. Philadelphia: Mosby Publishing; 2003:1645-1663.

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