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The Science that Says that MSG Places Humans at Risk

Epidemiologic studies completed in 1969 and the 1970's demonstrated that at least 25% of the population react to monosodium glutamate.(1-4) Today, we recognize that those reactions range from mild and transitory to debilitating and life threatening.(5)
 

MSG-sensitive consumers react to free glutamic acid (or free glutamate) that occurs in food as a consequence of a manufacturing process or fermentation -- regardless of the name of the ingredient that contains the processed free glutamic acid (MSG). The Food and Drug Administration has even acknowledged that consumers refer to all free glutamic acid as MSG.(6) Yet, consumers who choose to avoid MSG have great difficulty doing so, because more than 40 different food additives contain MSG without disclosure, and the number of such additives continues to grow.

 

Scientists have not determined the mechanism(s) that cause MSG reactions. It is known that the reactions are sensitivity reactions, i.e., reactions to a toxin or poison, as opposed to allergic (IgE mediated) reactions. It is known that MSG-sensitive consumers react to glutamic acid only in its free form, and only if it has been released from protein through a manufacturing process or fermentation.

It is known that free glutamic acid found associated with unadulterated protein, and glutamic acid bound in protein or freed from protein during normal digestion is L-glutamic acid only;(7-9) while free glutamic acid found in processed food contains both L-glutamic acid and D-glutamic acid,(7-8) and may also contain other undesirable by-products that scientists refer to as impurities including pyroglutamic acid, mono and dichloro propanols, and/or heterocyclic amines.(10-11) The propanols and heterocyclic amines are carcinogenic.  

There are three neurotoxic amino acids commonly found in some food additives: glutamic acid, aspartic acid (found in aspartame, a sugar substitute), and L-cysteine.(12-13)  Free glutamic acid ingested as MSG can cross the placenta during pregnancy,(14-15) can cross the blood brain barrier in an unregulated manner during development, and can pass through the five circumventricular organs, which are "leaky" at best, at any stage of life.(16-17) In addition, the blood brain barrier can be compromised by such things as drugs, seizures, stroke, trauma to the head, hypoglycemia, hypertension, extreme physical stress, high fever, and the normal process of aging.(18)  It is generally accepted that the young are particularly at risk from ingestion of MSG.

 

MSG-sensitivity is difficult to diagnose because the reaction is not IgE mediated; because individual tolerance levels vary; and because MSG reactions may occur anywhere from immediately to 48 hours following ingestion. The key to diagnosis lies in the fact that an individual typically responds to MSG with the same reaction(s), and after the same elapsed time each time that MSG ingestion exceeds the individual's tolerance level. To date, there has been no systematic study to determine the minimum amount of MSG needed to cause an adverse reaction, and researchers have not yet found the mechanism(s) underlying sensitivity to MSG.

   

For further information regarding MSG, please visit our Web site at http://www.truthinlabeling.org

Also, feel free to call or e-mail the Truth in Labeling Campaign at 858/481-9333 or adandjack@aol.com

 

REFERENCES

1. Kenney, RA and Tidball, CS Human susceptibility to oral monosodium L-glutamate. Am J Clin Nutr. 25:140-146, 1972.

2. Reif-Lehrer, L. Prevalence of Chinese restaurant syndrome. Federation Proceedings 35:1617-1623,1977.

3. Kerr, GR, Wu-Lee, M, El-Lozy, M, McGandy, R, and Stare, F.Food-symptomatology questionnaires: risks of demand-bias questions and population-biased surveys.In: Glutamic Acid: Advances in Biochemistry and PhysiologyFiler, LJ, et al., eds.New York: Raven Press, 1979.

4. Schaumburg, HH, Byck, R, Gerstl, R, and Mashman, JH. Monosodium L-glutamate: its pharmacology and role in the Chinese restaurant syndrome. Science 163:826-828,1969.

5. Analysis of Adverse Reactions to Monosodium Glutamate (MSG).Prepared for the Center for Food Safety and Applied Nutrition, Food and Drug Administration.Raiten, DJ, Talbot, JM, and Fisher, KD, eds.Bethesda, Maryland: Life Sciences Research Office of the Federation of American Societies for Experimental Biology, July, 1995.

6. FDA Backgrounder on the Subject of Monosodium Glutamate (MSG).August 31, 1995.

7. Rundlett, KL, and Armstrong, DW.Evaluation of Free D-Glutamate in Processed Foods. Chirality 6:277-282, 1994.

8. Man, EH, and Bada, JL.Dietary D-Amino Acids. Ann. Rev. Nutr. 7:209-25,1987.

8. Analysis of Adverse Reactions to Monosodium Glutamate (MSG).Prepared for the Center for Food Safety and Applied Nutrition, Food and Drug Administration.Raiten, DJ, Talbot, JM, and Fisher, KD, eds.Bethesda, Maryland: Life Sciences Research Office of the Federation of American Societies for Experimental Biology, July, 1995.Page 9.

10. Pommer, K.(Novo Nordisk BioChem Inc., Franklinton, NC) Cereal Foods World. October, 1995 Vol 40. No 10. Page 745.

11. Analysis of Adverse Reactions to Monosodium Glutamate (MSG).Prepared for the Center for Food Safety and Applied Nutrition, Food and Drug Administration.Raiten, DJ, Talbot, JM, and Fisher, KD, eds.Bethesda, Maryland: Life Sciences Research Office of the Federation of American Societies for Experimental Biology, July, 1995.Page 32.

12. Olney, JW, Ho, OL, and Rhee, V. Brain-damaging potential of protein hydrolysates. N Engl J Med 289:391-393, 1973.

13. Schainker, B, and Olney, JW. Glutamate-type hypothalamic-pituitary syndrome in mice treated with aspartate or cysteate in infancy. J Neural Transmission 35:207-215,1974.

14. Frieder, B, and Grimm, VE. Prenatal monosodium glutamate (MSG) treatment given through the mother's diet causes behavioral deficits in rat offspring.Intern J Neurosci. 23:117-126,1984.

15. Gao, J, Wu, J, Zhao, XN, Zhang, WN, Zhang, YY, Zhang, ZX. [Transplacental neurotoxic effects of monosodium glutamate on structures and functions of specific brain areas of filial mice.] Sheng Li Hsueh Pao Acta Physiologica Sinica. 46:44-51,1994.

16. Price MT, Olney JW, Lowry OH, Buchsbaum S.Uptake of exogenous glutamate and aspartate by circumventricular organs but not other regions of brain. J. Neurochem. 36:1774-1780,1981.

17. Broadwell RD, Sofroniew MV. Serum proteins bypass the blood-brain fluid barriers for extracellular entry to the central nervous system.Exp Neurol. 120:245-263. 1993.

18. Blaylock, RL. Excitotoxins: The Taste That Kills. Santa Fe, NM: Health Press; 1994.