MSG Allergy - Chinese Restaurant Syndrome

MSG, also known as monosodium glutamate or sodium glutamate is the sodium salt of the non-essential amino acid, glutamic acid. One sodium molecule stuck to one glutamic molecule makes monosodium glutamate. The white crystalline powder of MSG is a flavor enhancer and a popular food additive. It does not have any particular taste of its own, however, it enhances the flavor of the food by stimulating the taste buds. This flavoring additive has been part of Asian cuisine for centuries. However, it's unclear if it were the Chinese or Japanese who first discovered this.

MSG is widely used in Japanese cooking (called Ajinomoto) and Chinese food. Further, MSG is also a popular flavoring agent in North America and is sold under the brand name 'Accent'. Today MSG has found its applications in canned foods, processed meat, soups and similar products. MSG resembles salt or sugar and is made from fermented sugar beet or sugar cane molasses.

What is MSG Allergy?

An MSG allergy can be termed as allergic reactions to a combination of ingredients or allergic reaction to monosodium glutamate itself. Some researchers say that there is no such thing as MSG allergy and attribute the allergic reactions to food intolerance or food sensitivity. The reason why they say it cannot be MSG allergy 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 the 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 into rise in histamine level in the blood, thereby resulting into allergic like symptoms. MSG can aggravate allergies to other foods. 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, this allergic like symptoms caused by MSG are called Chinese restaurant syndrome.

Symptoms of MSG allergy

The symptoms of this Chinese restaurant syndrome appear an hour or so after the consumption of MSG food items. Usually the symptoms disappear after two to three hours. When the reactions are severe the emergency treatment is required. The commonly observed symptoms are:

• Burning sensation on the torso, thighs, shoulders, neck and arms
• Chest pain or palpitations
• Sub-sternal discomfort
• Numbness near the mouth
• Sensation of facial pressure
• Sensation of facial swelling
• Nausea and vomiting
• Flushing and sweating
• Headache
• Wheezing

Is MSG safe?

MSG was classified as a "generally recognized as safe" food additive by the FDA in 1959, under the Federal Food, Drug, and Cosmetic Act. However, MSG's use has stirred lots of controversies. Research conducted during the 1980s revealed that glutamate played a significant part in the normal functioning of the nervous system. This revelation raised several eyebrows! Could consumption of glutamate via food have have an effect on the nervous system? Further, to add to the concern, the FDA received several reports of people suffering from headaches, nausea, vomiting, palpitations after MSG added foods. However, nothing much was confirmed with respect to this. The growing concerns lead the FDA to sponsor various safety assessments. The conclusion was 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 reaction 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 a MSG Symptom Complex (short term reactions) which categorized the people into two groups. The first group comprises those people who develop allergic symptoms on consumption of large doses (3 gm or more per meal) of MSG, especially on an empty stomach. Typically less than 0.5 grams of MSG is added to flavor the food items. The second category involves people with severe and poorly controlled asthma. Asthmatics may develop breathing difficulties in addition to the other short term symptoms.

The symptoms of MSG allergy go away on their own, however, if they persist the patients are treated with antihistamines, corticosteroids, epinephrine as seen in case of any allergic reaction. If you suspect that you have an MSG allergy then 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.