MSG, Excitotoxins, Glutamate, and FGA: A Primer

I’m not here to preach the evils of MSG and it’s relatives. I’m not out to change the world right now, just help my family and others like us feel better.  Whether you believe these substances are harmful to everyone, or you just want to see this as similar to “an allergy”, doesn’t really matter to me.  But if you suspect MSG is a problem, perhaps I can help you find where it is hiding.  (hint: the answer is very close to “everywhere”, I’m sorry to say).  (If you want to read a little bit about our story, see the previous post,

First, I thought I should start with a quick primer on terms.  One overall bucket term I’ll use is “excitotoxins”. According to Wikipedia, “Excitotoxicity is the pathological process by which nerve cells are damaged and killed by excessive stimulation by neurotransmitters such as glutamate and similar substances. This occurs when receptors for the excitatory neurotransmitter glutamate (glutamate receptors) such as the NMDA receptor and AMPA receptor are overactivated.”  The book to read if you are interested in understanding more is Excitotoxins: The Taste that Kills by respected neurosurgeon Russell Blaylock, MD. (You can also see videos on YouTube with the same name as the book).

The most prevalent excitotoxins are glutamate and artificial sweeteners (I’ll have to post separately on these, but suffice to say that I’ve found evidence that all are excitotoxins to different degrees, though not everyone agrees).

Glutamate, a.k.a Glutamic Acid, is a widespread amino acid. In neuroscience, glutamate is an important neurotransmitter that plays a key role in long-term potentiation and is important for learning and memory. Glutamate is found naturally in all living cells, primarily in the bound form as part of proteins.

So, if it is so important, why do we avoid “glutamates”?  There are a few theories on this.  The biggest functional difference is whether the glutamate is bound or not. Only a fraction of the glutamate in foods is in its “free” form, and only free glutamate, free glutamic acid (FGA), can enhance the flavor of foods.  My experience is that we only see reactions to the free form.

Jack Samuels, a leading advocate against MSG and excitotoxins being added to our food, speculates that people are reacting to a different form of glutamic acid, a stereoisomer D-glutamic acid,  that is created by high heat and acid processing (which is true of most food additives, “natural” or not): This does hold true with my experience. Our son has never had a reaction to an unprocessed food that I know of. However, he is very sensitive but still not as sensitive as some people, so as with all of this, YMMV — “your mileage may vary”.

What about MSG itself? MSG is the sodium salt of glutamic acid, or free glutamic acid attached to a sodium.  The main reason MSG is so toxic is that it is extremely concentrated, though some argue that the form is different. I’ve not needed to research this much as we just avoid it.

So the upshot of this is that we need to worry not just about MSG, but a whole variety of foods that have been processed and concentrated to the point where they have significant amounts of FGA.  Here is my favorite list, though not in the order that I would put them in (I’ll write about that separately):

That’s enough information for one post.  Stayed tuned for more!  And remember, one bite at a time.



  1. Eating That Elephant » Blog Archive » Eliminating Excitotoxins:

    […] MSG, Excitotoxins, Glutamate, and FGA: A Primer […]

  2. Cat L:

    thanks for all the resources and help!

  3. Lisa:

    You are very welcome, Cat! I’m really glad this information is helping you guys.

  4. Gretchen Axelson:

    Thanks so much Lisa. I have only recently realized that FGA is terrible for me. What a relief to know how to prevent feeling so bad. Your resource is invaluable to me.

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