The food products that we eat, impart their taste from the taste enhancers and additives added to them. Monosodium Glutamate is one of them. It is a common flavor enhancing food additive used in the Asian food industries. Its popularity is attributed to its potential abilities to stimulate the taste buds effectively by imparting an exotic taste to the food items. It is mainly added to fast foods and junk food items.
Facts about MSG
Monosodium Glutamate is basically the sodium salt of glutamic acid. Glutamic acid is one of the non-essential amino acids i.e. naturally produced inside the human body. It is also found in tomatoes, grapes, cheese, and mushrooms.
Sodium constitutes the 12% of the MSG and the remaining is the glutamate portion which is mainly an outcome of fermentation of starches. However, MSG was originally obtained from seaweed but is now mainly made from the bean and cereal protein.
Visibly MSG is a white crystalline powder that looks somewhat similar to the table salt or sugar. Monosodium Glutamate is structurally represented as,
Its chemical formula is C5H8NO4Na with a molar mass of 169.11 g/mol.
Foods with MSG
Glutamates are attributed to impart a meaty, savory popularly known as “Umami” taste to the food. In addition to its own particular taste, MSG enhances and intensifies the other flavors in the product also. MSG is very popular in Asian Cuisines and you can easily find Asian grocery stores selling sacs of pure MSG. Moreover, Latin American and Caribbean cuisines also employ MSG, particularly in spice rubs.
MSG is commonly found in chicken dishes and various commercially packaged foods like; cheese-flavored chips and crackers, canned soups, instant noodles, seasoning salt, bouillon cubes, salad dressings, gravy mixes, pre-made gravies, cold cuts and hot dogs and soy-based (i.e. vegetarian) varieties. It must be noted that not all foods containing MSG are labeled with it. Hydrolyzed protein, autolyzed yeast, and sodium caseinate are all alternative labels for MSG.
Safety and Health concerns regarding MSG
The U.S. food and drug administration authorities claim MSG to be safe. They generally recognize it safe to use. However, MSG is still reported to cause various health issues among the majority of its consumers. Some people may have sensitivity issues with a high quantity of MSG while others may be highly allergic to it. Headaches, nausea, dizziness, excessive sweating, skin rash, numbness, sleepiness, ringing ears, intense thirst, irregular heartbeat, and skin rashes are common consequences reported with high MSG consumption.
The negative reputation of the additive was first reported in the 1960s. A letter was published in The New England Journal of Medicine from a Maryland doctor named Robert Ho Man Kwok. He shared his experience that every time he ate from a Chinese restaurant, he experienced symptoms of an allergic reaction. He questioned the wine he was drinking, the spices in the food, or the MSG for the side reactions. Kwok’s letter stated the symptoms that were found similar to those of “Chinese Restaurant Syndrome,” or CRS. Similarly, other people began to write into the journal about their own experiences. Some reported flushed feelings, some said they had a headache after consuming Chinese food.
Soon after that, a neuroscientist named John Olney published a study on MSG. He carried out experiments using white laboratory mice. He directly injected the additive into the mice. He reported various neurological disorders in his subjects which included brain lesions or impaired development. The letter and the analysis of the study declared MSG to be the culprit behind CRS. However, there were certain objections implied in the study.
John Fernstrom, a professor of psychiatry, pharmacology, and chemical biology at the University Of Pittsburgh School Of Medicine, stated that the problems could have arisen because the mice were directly injected with MSG under their skin whereas; the MSG consumed by humans is largely metabolized in the gut before it reaches the bloodstream. Moreover, the amount of MSG injected into the mice was far greater than the amount consumed by the humans in their food. Thus, MSG cannot be 100% blamed for the problems. Thus, the use of MSG still remains controversial.
Diseases associated with MSG
Following are some diseases that are commonly reported to be associated with high intake of MSG.
Migraines and Headaches
Headaches or migraines are a common outcome of any possible food additive or enhancer. A study was conducted by researchers in order to determine a link between MSG intake and headaches. It involved about 14 men who were given sugar-free sodas with either MSG or a placebo. Researchers found that MSG significantly increased headaches. The results were published in the January 2010 issue of the journal “Cephalalgia.”
Fibromyalgia is a disorder that causes widespread pain. It affects the muscles and soft tissues. It is characterized by chronic muscle pain, fatigue, sleep problems, and painful tender points. A study conducted in fibromyalgia patients, who also had irritable bowel syndrome, reported that removing MSG from the diets of the patients significantly improved their fibromyalgia symptoms. On the other side, re-introducing MSG caused a return of symptoms with greater severity. The study was published in the journal of “Clinical and Experimental Rheumatology” in the November 2012 issue.
Chinese Restaurant Syndrome
Chinese restaurant syndrome is a set of symptoms that people experience after eating Chinese food. It may be an outcome of the sensitivity of the food additives such as MSG. Symptoms may include chest pains, headache, sweating, flushing, numbness or a burning sensation around the mouth, and pressure on your face or the feeling of facial swelling. However, there are minimal scientific evidences showing a link between MSG and these symptoms in humans.
MSG is often linked to weight gain and obesity. In China, an average intake of MSG ranging from 0.33-2.2 grams per day has been linked to weight gain on several occasions. However, in Vietnamese adults, 2.2 grams of MSG per day is not reported hazardous to weight.
In addition, the taste of Umami, provided by MSG, is declared to regulate appetite by stimulating receptors found on the tongue and walls of the digestive tract along with the release of appetite-regulating hormones like “Cholecystokinin” and “GLP-1”.
One recent controlled trial in humans showed that MSG also raised blood pressure. However, all of these studies used unrealistically high doses thus cannot be taken for granted.
Is MSG an Excitotoxin?
Glutamate functions as an “excitatory” neurotransmitter in the brain. It means that it can potentially excite nerve cells in order to relay its signals. People usually accredit MSG to promote excessive glutamates in the brain which consequently results in excessive stimulation of nerve cells. For this reason, MSG has been referred to as an excitotoxin.
“Excitotoxins: The Taste That Kills” was a book published by the neurosurgeon Dr. Russell Blaylock in 1996. It included certain arguments that nerve cells can be destroyed by the excitatory effects of glutamates using MSG. Similarly, a study reported a megadose of MSG increased blood levels of glutamates by 556%. On contrary, dietary glutamate is said to have a little or no effect on the human brain because it is unable to cross the blood-brain barrier. Overall, there doesn’t seem to be any compelling evidence that MSG acts as an excitotoxin when consumed in normal amounts.
MSG or monosodium glutamate is a common food additive in the food industry. It enhances the taste of the food like no other enhancer does, thus is quite popular. Various studies link it with different disorders but all of them have certain objections with them. Thus, the use of MSG and its contribution to potential health risks is still a controversial subject. People allergic to it are highly prohibited to consume it. They must opt for restaurants and regular food products after carefully investigating the extent of the use of MSG in them.