Monosodium Glutamate (MSG) is used as a flavor enhancer in a variety of processed foods and restaurant items. MSG enhances your ability to taste a flavor called umami, which is the savory flavor found in protein-rich foods like fish, meats and milk.
Since MSG enhances the flavor of protein-rich foods, it may be beneficial for people who don't have strong appetites or who have lost some of their sense of taste. Using MSG can help improve the taste perception in the elderly, many of whom suffer from malnutrition because they no longer enjoy eating. For those of us with normal tastebuds, the MSG adds to the intensity of the flavor.
The United States Food and Drug Administration states that MSG is safe in the amounts typically found in American's diets. Under current FDA regulations, MSG must be identified as "monosodium glutamate" in a food label's ingredient list.
You may also find small amounts of monosodium glutamate in foods that contain hydrolyzed vegetable proteins, which are also used for enhancing flavor. Hydrolyzed vegetable proteins are broken down pieces of proteins called amino acids, including glutamate, which can combine with sodium to form MSG. Food manufacturers will list hydrolyzed vegetable protein in the ingredients, but do not need to state the presence of MSG.
Monosodium Glutamate Sensitivity
There were many anecdotal reports of adverse reactions to MSG in the 1980s and 1990s; however, research has produced mixed results. It's unclear how much of an effect MSG has on allergies and asthma. Reactions attributed to MSG include headache, flushing, sweating, nausea, numbness, tingling or burning in or around the mouth, weakness, rapid heart beat, chest pain and shortness of breath.
The reported reactions to MSG are usually mild, although some people claim their symptoms are severe. It is difficult to pin the reactions directly on MSG because many people experience the adverse affects several hours after eating -- it may be that the symptoms are coincidental with the use of MSG rather than caused by it.Sources:
Food Safety: Natural Flavorings on Meat and Poultry Labels. United States Department of Agriculture. Accessed July 28, 2009. http://www.fsis.usda.gov/Help/FAQs_Flavorings/index.asp
Monosodium L-glutamate. United States Food and Drug Administration. Accessed July 28, 2009. http://www.accessdata.fda.gov/scripts/fcn/fcnDetailNavigation.cfm?rpt=scogsListing&id=217
Williams AN, Woessner KM. "Monosodium glutamate 'allergy': menace or myth?" Clin Exp Allergy. 2009 May;39(5):640-6.