What Are the Symptoms of MSG Allergy?

Why Reactions to MSG Aren't Really Allergies

MSG Allergies
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MSG, or monosodium glutamate, is a flavor enhancer comprised of the sodium salt of glutamic acid. This compound is a naturally occurring amino acid and is produced by fermenting starch, sugar beets, sugar cane, or molasses, a process similar to that used to make yogurt, vinegar, and wine. MSG is found naturally in many foods, including seaweed, tomatoes, and cheese as well as many canned vegetables, soups and processed meats.

 

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.

Because there is very little evidence that a true MSG allergy exists, the Food and Drug Administration (FDA) has classified MSG as an ingredient that's "generally recognized as safe." However, because its use has historically provoked controversy, the FDA requires food labels to list it as an ingredient. 

The Symptoms of MSG "Allergy"

Many people describe adverse reactions after consuming MSG, commonly (and pejoratively) referred to as “Chinese Restaurant Syndrome” because MSG it has traditionally been used in Asian cooking.

But most people who are affected will experience only mild and short-lasting symptoms shortly after eating foods containing MSG. These symptoms may include: 

  • Numbness on the back of the neck, shoulders, and arms 
  • A sense of generalized weakness
  • Heart palpitations
  • Facial pressure
  • Headaches
  • Nausea
  • Chest pain
  • Drowsiness

Despite widespread anecdotal evidence that some people experience these reactions, studies on MSG have not demonstrated a clear cause-and-effect relationship. While few studies have shown that mild reactions may occur after MSG is consumed in large amounts, the threshold for symptom development is typically far above what would be consumed during a normal MSG-containing meal. 

Testing for MSG Allergy

Because sensitivity to MSG is not generally accepted as a true allergy, there is no test available to determine whether you are sensitive to it. For example, skin tests and blood tests are not available as they are with other food and environmental allergies.While it is possible to perform an oral challenge to MSG, as an allergist, I haven't seen this done very often. 

How to Avoid MSG Reactions

Avoidance of MSG is the only preventative measure you can take to avoid a reaction. Following a preservative-free diet may be one way of avoiding MSG. FDA labeling requirements make it easier to avoid MSG-containing foods you can buy, but eating in restaurants may prove to be trickier.

 

Learn more about allergic reactions to food additives and preservatives.

Source:

FDA Q&A on MSG. fda.gov. March 2016.

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