Monosodium Glutamate

Grunge rubber stamp with text No MSG,vector illustration

Monosodium glutamate (MSG or E-621 in Europe). is a flavor enhancer widely used to make foods tastier and to entice people to eat more of whatever it is in.   Food services in nursing homes often add it to foods because the elderly often suffer from poor appetite and MSG encourages eating more.

MSG is related to glutamic acid, an amino acid naturally occurring in foods such as tomatoes, Parmesan cheese, potatoes, mushrooms, and other fruits and vegetables, as well as edible seaweeds.  Furthermore, glutamates are important neurotransmitters in the brain involved in learning and memory.  However, the naturally-occurring MSG is “bound” to other components in the food, while it is a “free glutamate” when used as an additive.  It is generally this “free” glutamate that can cause health problems.

Moreover, MSG is an excitotoxin; this means it can excite nerve cells until they die.  It has been implicated in a variety of symptoms ranging from migraine headaches, tingling, flushing, and nausea to difficulty breathing.  Those that promote the use of MSG claim that none of these symptoms can be proven experimentally to be caused by MSG because they are anecdotal.  Indeed, when you think about it, a headache is anecdotal by its very nature – how would you measure it?

Author Index
  1. Ali 2000
  2. Ali 2012
  3. Chevassus 2002
  4. Collison 2012
  5. Collison 2013
  6. Egbuono 2010
  7. Feria-Velasco 1995
  8. Feria-Velasco 2006
  9. He 2008
  10. He 2011
  11. Hong 1981
  12. Husarova 2013
  13. Insawang 2012
  14. Jo 2008
  15. Kiss 2007
  16. Lau 2006
  17. Lau 2010
  18. Ohguro 2002
  19. Onaolapo 2011
  20. Pacor 2004
  21. Park 2012
  22. Prandota 2003
  23. Quines 2014
  24. Quines 2015
  25. Rajan 2014
  26. Savcheniuk 2014
  27. Settipane 1987
  28. Shovic 1999
  29. Simon 2000
  30. Squibb 1981
  31. Strong 2000
  32. Tarasoff 1993
  33. Tawfik 2012
  34. Van Bever 1989
  35. Yang 1997
Husarova 2013: Review of MSG toxic effects
Monosodium Glutamate Toxic Effects and Their Implications for Human Intake: A Review, Husarova V & Ostatnikova D., JMED Research. 
Monosodium Glutamate (MSG) is one of the world’s most widely used food additives. Its toxic effects have been shown in numerous animal studies, however in most of them, the method of administration and the doses were not similar to human MSG intake. In this paper we review animal and human studies in which MSG effects on central nervous system, adipose tissue and liver, reproductive organs and other systems have been shown and we discuss their implications for human MSG intake.
Quines 2014: MSG makes rats anxious and depressed

Monosodium glutamate, a food additive, induces depressive-like and anxiogenic-like behaviors in young rats, Quines CB, Rosa SG, Da Rocha JT, Gai BM, Bortolatto CF, Duarte MM, Nogueira CW., Life Sciences, 2014 Jun 27;107(1-2):27-31

MSG-treated rats are more susceptible to develop anxiety and depression-like behaviors, which could be related to a dysfunction in the serotonergic system.

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MSG in the Diet

For most people, naturally occurring MSG is not a problem, being bound to the proteins in the food; when added to foods as a chemical additive, however, it is a “free” glutamate and can have a very different outcome.

MSG hides under a host of other names including:

  • HVP (hydrolized vegetable protein)
  • Autolyzed yeast
  • Yeast extract
  • Flavoring
  • Spices