Monosodium glutamate is a flavor enhancer , which is added to other flavors to avoid having to use them in high doses.
The flavoring capacity of glutamate is exploited by the food industry to enhance the flavor of stored products, meats, fish and some types of vegetables.
A few years ago a research was conducted in the United States in which a group of children were made to taste fried chicken legs treated with and without glutamate. As many as 95% of the children expressed their preference for glutamate-enriched chicken. In fact, our language there are specific receptors of taste with a marked sensitivity to this substance; the recent discovery of their existence unquestionably demonstrates the presence of a fifth taste, in addition to the classic quartet given by sweet , salty, sour and bitter.
Chemistry and production of monosodium glutamate
Monosodium glutamate is a white crystalline powder, obtained from glutamic acid, a non-essential but extremely widespread amino acid in nature (especially in seaweed , vegetables and sugar beets ).
It was discovered in the 1920s by a Japanese scientist and still today the “Rising Sun” is among the major producers of monosodium glutamate.
The world consumption of this additive is estimated at about two hundred thousand tons per year, very respectable numbers, especially if we consider that a few mg are enough to enhance the flavor of a food. In a normal meal we can get to take up to twenty times higher quantities than those normally present in food.
In 1925, the owner of a US milling industry discovered an innovative method of extracting glutamate from wastewater resulting from the fermentation of molasses, stillage and also from glucose syrups .
Which foods are richest in sodium glutamate ?
The foods in which sodium glutamate is widely used are stock cubes , canned meat and vegetables, cold cuts , frozen or freeze-dried products and some ready meals.
Often, the use of this additive is masked by the abbreviations ranging from E620 to E625 . The Parmesan cheese , together with vegetables nuts and canned peas , is one of the richest foods in absolute monosodium glutamate.
Parmigiano Reggiano is one of the richest foods in monosodium glutamate. The average quantity in 100 grams of Parmesan cheese is approximately 1.6 grams. It should be noted that it is natural glutamate , that is, originally contained in the milk used for the production of cheese ; the glutamate of Parmesan, therefore, is not an additive introduced during production.
Chinese cuisine, in particular, makes extensive use of a seaweed that has the sodium salt of glutamic acid as its active ingredient .
Who should limit the use of monosodium glutamate?
Monosodium glutamate, while having the same perception threshold as table salt for the salty taste, contains less than a third of sodium. In any case, those who follow a low-sodium diet should also reduce the consumption of processed foods that contain it.
Monosodium glutamate should also be avoided by people with asthma or people allergic to aspirin .
Is monosodium glutamate bad for you?
Today glutamate is considered a safe additive, although there has been controversy over its safety in the past. In the 1960s, for example, the so-called ” Chinese restaurant syndrome ” spread , which caused skepticism towards this ingredient to grow dramatically. In those years it was in fact demonstrated the existence of a relationship between the consumption of glutamate and the appearance of symptoms such as headache , dizziness , palpitations and hot flashes in predisposed subjects.
The “allergenic” power of glutamate derives from its ability to lower the excitability threshold of neurons .
The results of another study that associated the prolonged use of monosodium glutamate with the progressive thinning of the ocular retina were already known from the 1950s ; according to the most recent research results, the chronic intake of this additive would even cause neurological disorders , facilitating the onset of neurodegenerative diseases .
However, it must be emphasized that most of the research conducted up to now has denied the alleged problems of chronic toxicity and carcinogenicity deriving from the prolonged use of the additive object of this article.
Precautions and Warnings
Chinese restaurant syndrome: does it exist?
“Why do I get headaches every time I eat in Chinese restaurants ?”
In Chinese cuisine, large quantities of monosodium glutamate are used to improve the flavor of recipes; however, many people seem to have poor tolerance to this additive, often complaining of headaches and numbness in the back of the neck, which can radiate to the arms. Others report slightly different symptoms, including headache (mild to severe), tightness in the chest, pressure on the cheeks and jaw , slight changes in mood, weakness, tingling, burning sensations, heart palpitations or sleep disturbances. Some claim to have experienced asthma-like symptoms after consuming even small amounts of monosodium glutamate.
These temporary but unpleasant symptoms are often so mild that they go unnoticed, making it difficult to estimate how many people are sensitive to MSG. Furthermore, the appearance of ANY symptoms should not be associated with the effects of monosodium glutamate; there is in fact another very frequent complication that determines the appearance of symptoms such as: skin redness , itching , gastrointestinal disorders, hypotension , dizziness , tachycardia and rhinitis with sneezing . This is theintolerance to histamine , which can be manifested by consuming foods rich in histamine (such as poorly preserved fish , blue cheeses , beer , wine, etc.) and those histamine liberating ( chocolate , seafood , strawberries , milk, eggs , alcohol, etc.) .
On the other hand, the reaction between monosodium glutamate in Chinese recipes and the appearance of specific symptoms is so widespread that it is called the Chinese restaurant syndrome.
In case of sensitivity to monosodium glutamate it is necessary to reduce the intake of the additive or to eliminate it completely. Doctors have not yet established a maximum safe dose because tolerance is extremely individual. In general, the greater the amount of monosodium glutamate in the diet, the more likely it is that symptoms will appear. Moreover, as anticipated, those suffering from sodium- sensitive primary arterial hypertension should reduce or better eliminate the amount of monosodium glutamate in the diet. If the symptoms become so annoying that they affect well-being
general psychophysical, it is recommended to consult an allergist and eliminate all foods containing monosodium glutamate for at least two weeks. This last intervention may not be simple, especially for those who often eat away from home and / or use packaged products; it is recommended to carefully consult the nutritional labels and / or to warn the catering staff about your condition.
Among the homemade ingredients, those that contain the most are the classic broth cube and soy sauce .
In the food labels , the presence of flavor enhancers containing similar or glutamate may also be revealed by the words: extract of yeast , protein vegetable hydrolysed or HVP, glutamate potassium , sodium caseinate, broth, natural flavors or aromas simply.
Monosodium glutamate and infant nutrition
Currently in Europe the use of monosodium glutamate has been prudently banned in foods intended for infants .
Misleading use of monosodium glutamate
Beyond its alleged or actual toxicity (the debate is still heated today among health-conscious, consumers, restaurateurs and industrialists), the use of glutamate remains substantially “a deception for the consumer”, since it is often used to improve the flavor of food products prepared with poor quality raw materials.