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MSG Allergy - Chinese Restaurant Syndrome

Priya Johnson
Monosodium Glutamate or MSG is a white, crystalline powder, commonly used as a food additive in Asian cuisine. Some people are seen to develop allergic reactions after consuming food containing MSG. The story reveals more about MSG allergy, its symptoms and safety concerns.
MSG, also known as Ajinomoto (in Japan), Weijing (in China) and Accent (North America), it is a flavor enhancer and food additive, widely used in Asian cuisine for centuries. Today, MSG has found its applications in canned foods, processed meat, soups and similar products.
It resembles salt or sugar and is made from fermented sugar beet or sugarcane molasses. MSG has no particular taste of its own, however, it enhances the flavor of the food by stimulating the nerve cells in the mouth and brain.
MSG is the sodium salt of the non-essential amino acid, glutamic acid and is naturally found in high amounts in tomatoes, seaweed, Chinese cabbage, mushrooms and Parmesan cheese. One sodium molecule stuck to one glutamic molecule makes monosodium glutamate.
The crystalline form of MSG was first introduced into the market, by a Japanese company, Ajinomoto Corporation in the year 1909. Earlier MSG was isolated from seaweed, but, today it is obtained by fermentation of potatoes, corn and rice for commercial purposes.

What is MSG Allergy?

MSG allergy can be termed as an allergic reaction to a combination of ingredients or allergic reaction to monosodium glutamate itself. Researchers say that there is no such thing as MSG allergy and attribute the allergic reactions to food intolerance or food sensitivity. The reason they say so, is because whenever a food ingredient causes an allergy, there has to be some kind of protein involved, which is considered harmful by the body.
In a food allergy, the immune system of the body produces antibodies against the proteins, thinking they are foreign bodies. The antibodies trigger allergic reactions. However, when MSG is ingested, no such antibodies are seen to be released.
MSG is the sodium salt of glutamic acid, which is a neurotransmitter. Neurotransmitters stimulate the nerve cells; stimulate the sense of smell, taste and can even stimulate hunger. It's just like alcohol or caffeine that has different effects on different people.
The neurotransmitters from MSG are capable of overexciting the nervous system in some people. The nerve cells fire and result in rise in histamine level in the blood, thereby resulting in symptoms like those seen during other allergic reactions.
However, MSG can aggravate food allergies. For example, if one is mildly allergic to soy products, then in a dish comprising soy and MSG, the MSG can exacerbate the allergic reaction to the former. Since MSG is a common ingredient in Chinese restaurant cuisine, the symptoms resulting after consumption of MSG containing food products is termed as Chinese Restaurant Syndrome.

Symptoms of MSG allergy

The symptoms of Chinese restaurant syndrome appear an hour or so after the consumption of MSG food products. Usually the symptoms disappear after two to three hours. When the reactions are severe, emergency treatment is required. The commonly observed symptoms are:
  • Chest pain or palpitations
  • Substernal discomfort
  • Numbness near the mouth
  • Sensation of facial pressure
  • Sensation of facial swelling
  • Nausea and vomiting
  • Flushing and sweating
  • Headache
  • Wheezing
  • Burning sensation on the torso, thighs, shoulders, neck and arms

Is MSG Allergy a Myth?

MSG allergy has given birth to scores of debates over the decades. So what is this commotion all about? Well, let's get this cleared that MSG allergy is a myth! Then how did this syndrome come into existence? It was in the 1950s, when a physician published his observations after consumption of Chinese food in the New England Journal of Medicine.
He wrote about how he experienced symptoms like numbness at the nape, fatigue, palpitations, etc. He was also sure about his findings and took no time to nail MSG as the culprit. Panic overtook the masses and some even labeled MSG as toxin.
The growing concerns among the masses, lead the FDA to sponsor various safety assessments. Several studies were conducted as a result of the physician's publication, but, even after a decade of experiments, no connection between MSG and allergies could be found.
Thus, no ground was found for the physician's speculation, which is why MSG could not be considered an allergen. Scientists came to a consensus that MSG is safe, when consumed at levels that are generally used in cooking and in the food industry.
In 1986, the FDA's Advisory Committee on Hypersensitivity to Food Constituents, stated that MSG was safe, though it was seen to trigger short-term reactions in some individuals. In 1995, the FDA along with a group of independent scientists from the Federation of American Societies, for Experimental Biology (FASEB) conducted a detailed study on the effects of MSG. They concluded that no connection was found between MSG and any long-term illness or disorder.
Their report spoke about the identification of an MSG Symptom Complex (short-term reactions). People with severe or poorly controlled asthma were seen to develop short-term allergic symptoms on consumption of large doses (3 gm or more per meal) of MSG, especially on an empty stomach. Whereas, restaurant food contains a minimal amount of 0.5 grams in a meal. This means MSG is not responsible for allergic reactions after consumption of Chinese food.
The so-called symptoms of MSG allergy go away on their own, however, if they persist the patients are treated with antihistamines, corticosteroids, epinephrine, etc. as seen in case of any allergic reaction. If you suspect you have an MSG allergy, you need to get this confirmed from the allergist.
If you are allergic to MSG, then you need to avoid food items with MSG added to them. This is the best way to avoid MSG reactions. The FDA has made it mandatory for food with MSG to have the fact listed on the food label. So check the label before you make your purchases!