Glutamic acid (flavor)#Safety as a flavor enhancer
In a so-called glutamate intolerance, commonly known as Chinese restaurant syndrome, is a short-term symptoms after describing some people with them after intake of glutamates (glutamic acid ), a nonessential amino acid that occurs naturally in all living things occurs as a component of proteins and in the brain, in addition, the function of an inhibitory ( anti- ) neurotransmitter in the central nervous system. Therefore, it is significant concentrations of natural ingredient in many foods. Glutamate else can be added as a flavor enhancer in preparations especially of Asian cuisine or convenience food products artificially the food. Scientific studies suggest that not Glutamate, but other dietary constituents or situational influences are the cause of the patient's complaints. It is certainly among them neither consequences of intoxication, nor of intolerance or allergy.
Occurrence
1866 glutamate by the chemist Heinrich Ritthausen was first isolated as a pure substance made of natural materials. It occurs in almost all foods to proteins and peptides bound before. The German Nutrition Society estimates that the usual European mixed diet contains about 8 to 12 grams of glutamate a day. In European foods containing yeast extract, bouillon cube, seasoning, cheese (particularly parmesan ), anchovies and ripe, concentrated or dried tomatoes particularly much natural glutamates. Even more natural glutamates are present in Asian diets, particularly in soy sauce and fish sauce. This glutamate sources are not classified as flavors and foods as a food additive and not receive an e - number (see Food Law).
1907 developed Ikeda Kikunae of the University of Tokyo for the first time a synthesis method for sodium glutamate. It also patented a process for the mass production. Nowadays, monosodium glutamate is produced by fermentation by Corynebacterium glutamicum from starchy plant products. Since glutamates are used in large quantities as a food additive especially in Asian cuisine and in almost all finished or semi-finished products for the food industry, also in potato chips and dried soups.
Symptoms
Only 10 to 20 minutes after receiving the prestigious as trigger substances leads to dry mouth, tingling or numbness in the mouth, itching in the throat, reddened skin areas (eg cheeks) with heat sensation, palpitations, ( temples ), headache, facial muscle rigidity, neck stiffness, joint pain and nausea.
Chinese restaurant syndrome
1968 first described an American doctor in a letter to the New England Journal of Medicine a number of acute problems of the above type, which he regularly feel after the visit of Chinese restaurants, and gave them the name Chinese restaurant syndrome. As numerous other cases of intolerance reactions after eating at such restaurants were known, was followed by a 1969 publication in which other authors the first time the hypothesis lined up, there is a causal link of the complaints with the food artificially added glutamates.
Criticism
Since then, there in the medical literature, numerous case reports. However, such reports can be in fundamental methodological error not control, and therefore are not case reports according to the rules of evidence based medicine conclusive. Anyway, it was not convincing that a group of substances, which is incorporated with the "normal " food in amounts of about ten grams daily without discomfort should result in additional recording as a flavor enhancer to complaints. In previously published on this issue controlled trials, particularly in the most meaningful blind studies, was because not even be shown that the diet additionally supplied Glutamate symptoms such as the " Chinese restaurant syndrome " trigger, even with such subjects, which even stopped for glutamate - sensitive. With them, however, a nocebo effect could increasingly prove: But the fear that they take Glutamate to himself, leads them, even if this is not the case in the experiments, to supposedly glutamate - specific complaints. In another research report, the study situation is summarized as follows: " [ ... ] studies indicate indication did the symptoms -observed in some experiments are not specific to MSG ingestion and can thus be elicited by other foods. Studies in Which MSG which administered in food rather than in pure form have gene rally shown a lack of symptoms altogether. Malthus, a causal relationship in between MSG and acute, temporary, and, self - limiting ' adverse reactions is far from established. "
Thus, these and other studies show that the observed in some experiments symptoms are not specific for the uptake of glutamates, but can also be caused by other foods such as shrimp, peanuts, fish and soy sauce or special herbs and additives. In particular, had studies in which Glutamate added to the food, was therefore not administered pure, found no clear evidence of glutamate - related complaints. Even in people who reported Chinese Restaurant Syndrome please join them on, double-blind trials showed no evidence of glutamate as the cause of their complaints, ruled in 1987, the scientific advisory committee of the Food and Agriculture Organization of the World Health Organization. Therefore, a relationship between glutamates and acute or temporary ailments deemed not proven.
The rather unequivocal scientific evidence, however, has not led to relevant support groups, Internet forums, supplier of nutritional supplements, mass media, medical practitioners, representatives of paramedical and other questioning the outmoded idea of a glutamate intolerance in principle. Thus, the weekly magazine Focus 2009 wrote an article with the statement " glutamate intolerance - sick from Chinese food " and pointed at the end for further consultation on a named Oecotrophologin the German Allergy and Asthma Federation.
Regulations
Glutamate are classified on the basis of the aforementioned studies of the health authorities in the U.S. and in most European countries as a health hazard. 1991 was therefore established by the Scientific Committee on Food ( SCF ) of the European Union, that no Permitted daily dose of glutamate was determined. In Germany sodium glutamate is only banned as an additive in baby food. Otherwise, six Glutaminsäureverbindungen are approved as additives for use in foods. According to food labeling regulation ( LMKV ) § 6 of the class name (flavor enhancer ) is followed by the trade name (name of the relevant Glutaminsäureverbindung or corresponding E-number ) to specify. The E-numbers E 620 - E 625 on the list of food additives are approved for the Glutamate. Even foods with no ingredient list (eg loose goods) must be marked on or near the product or as a poster by " flavor enhancer ". The maximum permissible concentration of glutamate additives in meat and canned fish and ready meals 1%, 2% in sauces and condiments in 50%. Although foods with the ingredients as yeast extract or wort contain no synthetic Glutamate and may therefore have the words' without flavor enhancers ", but contain increasingly natural glutamates.