Thursday, November 22, 2012

MSG Part 2. Is MSG and allergen?

If MSG was in a court of law accused of causing harm, the lawyer would be screaming ‘SHOW ME THE EVIDENCE’.  Speculative reports of ill harm after consuming MSG laced foods are rife and where there is smoke there is often fire.  But an evidence trail is needed, and in the case of MSG as an allergen the evidence is missing without a trace. In 2010 I watched a TV program while on holiday in New Zealand where the presenter talked with some authority and conviction about the food additive MSG being a major problem in foods.  The presenter was a local chef and he was going to prepare some good tasting Asian food without the MSG. After the show I requested the evidence to support the MSG harm proposition from the show’s producers.  To their credit they eventually responded with data, but it was not relevant to MSG as a ‘cause of harm’ in the food supply. The producers should have checked with any of the following organisations who have extensively reviewed the topic: The Joint Expert Committee on Food Additives of the United Nations; Food and Agricultural Organization and; World Health Organisation, all who placed MSG in the safest category for food additives. Or perhaps International and National bodies for the safety of food additives including: International Food Information Council; U S Food and Drug Administration; the National Academy Sciences; the European Community’s Scientific Committee for Food; and the American Medical Association who all report MSG safe for human consumption as a flavor enhancer. In Australia, FSANZ quoted from overwhelming evidence from considerable scientific studies to explicitly deny any link between MSG and "serious adverse reactions" or "long-lasting effects", declaring MSG "safe for the general population". The problem as I see it was the producers and presenter were naïve regarding the topic of MSG, but would have heard anecdotal evidence from unreliable sources that MSG was bad. They then produce a harmless cooking program further propagating the myth that MSG is harmful to the general public.   
The question remains why is MSG such a public-touchstone for allergens? The history is intriguing.  In 1968, Robert Ho Man Kwok, MD described a collection of symptoms he experienced after eating Chinese food. He coined the phrase “Chinese Restaurant Syndrome” (CRS) to describe these symptoms such as hypersensitive reaction; headache; tightness in the chest; asthma; flushing; body tingling in addition to numbness at the back of the neck and a feeling of pressure in the face and upper chest muscles.  He named many potential causes from the foods eaten and among them MSG was mentioned. It was MSG amongst all other contenders that was followed up by some other speculative reports in scientific literature.  Once it made the general media the foundation was set, MSG caused CRS. (It is important to note that I am not stating people do not suffer hypersensitive response to certain foods or CRS, but believing MSG is the cause before studies were conducted was premature.)
In 1970, Morselli and Garattini examined 17 males and seven females in a well-controlled study. The researchers administered 3 g doses of MSG in 150 ml of beef broth and evaluated the subjects every 20 minutes for a three-hour period. The researchers concluded that there was no evidence that CRS was associated with the ingestion of MSG.  Four additional double blind design (neither researchers nor subjects knew if the food contained MSG) studies with subjects who believed they adversely reacted to MSG have been conducted. In all cases the data were inconsistent with subjects responding to all stimuli including those without MSG, or none, including the foods with MSG.  The results were also inconsistent, meaning they could not be reproduced. The well-controlled science is conclusive, MSG is not a problem. Taking this into account can MSG be the problem? For the vast majority of people who believe they have an allergy/hypersensitivity/CRS to MSG, the evidence trail makes that clear that MSG is not the problem. It doesn’t mean there weren’t compounds in foods that caused a reaction, but it was not MSG.  I have included a relevant bibliography at the end of this blog for those who are interested in reading the studies mentioned. 
After all the evidence presented, if you are still adamant MSG is an allergen for you and others, then avoid foods with glutamate. In most countries the food label will show whether MSG has been used as an additive. The label will bear the food additive class name (e.g., flavor enhancer), followed by either the name of the food additive (e.g. MSG), or its International Numbering System (INS) number 621.    
Some Relevant Literature
Simon RA. Additive-induced urticaria: Experience with monosodium glutamate (MSG). J. Nutr. 130:1063S-1066S, 2000.
Tarasoff, L. & Kelly, M.F. Monosodium L-glutamate: A double-blind study and review. Food and Chemical Toxicology 1993; 31:1019-1035.
Kwok, R.H.M. Chinese Restaurant Syndrome. N. Engl. J. Med; 1968:17:796.
Morselli, P.L. & Garattini, S. Monosodium glutamate and the Chinese Restaurant Syndrome. Nature 1970; 227:611-612.
Kenney, R.A. The Chinese Restaurant Syndrome: An anecdote revisited. Food and Chemical Toxicology 1986; 24(4):351-354.
Wilkin, J.K. Does monosodium glutamate cause flushing (or merely “glutamania”)? J. Amer. Acad. Dermatol 1986;15:225-230.
Geha RS, Beiser A, Ren C, Patterson R, Greenberger PA, Grammer RC, Ditto AM, Harris KE, Shaughnessy MA, Yarnold PR et al. Glutamate Safety in the Food Supply: review of alleged reaction to monosodium glutamate and outcome of a multicenter double-blind placebo-controlled study. J. Nutr 2000;130: 1058S–1062S.
European Food Information Council. The facts on Monosodium glutamate. 2002. Center for Science in the Public Interest. Food additives.
(23) Carvan M. MSG: the controversy. LEDA at Harvard Law School, 1997.
(24) Rhodes J, Alison C, Titherley JA et al. A survey of the monosodium glutamate content of foods and an estimation of the dietary intake of monosodium glutamate. Food Additives and Contaminants 1991: 8:265-274.
(25) National Academy of Sciences, National Research Council. The 1977 Survey of the
Industry on the Use of Food Additives: Estimates of Daily Intake. Vol. 3, Washington,
D.C.: National Academy Press, 1979

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