What are the peer-reviewed scientific papers on the topic of whether
or not amino acids found in protein powders (which are most often
hydrolyzed
whey or similar...) may be "excitotoxins" in the sense of Russell
Blaylock, M.D.
(Blaylock already considers cysteine to be an excitoxin. I am
interested only in
  independent support for this assertion.)

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Request for Question Clarification by librariankt-ga on 06 Nov 2002 11:22 PST

Are you just looking for citations to papers?  Citations plus abstracts? Results?

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Clarification of Question by skipdexter-ga on 06 Nov 2002 19:30 PST

Citations would be good. Add abstracts, even better. Jackpot would
be finding text of paper online. 

Having said all this, the question is rather tightly focussed: I 
am curious whether researchers other than Russell Blaylock have
identified amino acids (e.g. cysteine, glutamine ) as "excitotoxic"
in the sense that Blaylock does. My provocation for this question
is the following. I have started using protein powders for health
and building muscle. I notice, further, that many of them admit
to being either "hydrolyzed" or "partially pre-digested" both of
which increase the amount and/or ramp up the bio-availability of
these acids in the gut significantly. It is Blaylock's contention
that this presents the body with an overload which it is unable to properly
process. The downstream negative effects are short-handed by Blaylock
as "excitotoxic".

There are certainly peer-reviewed papers on the excitotoxicity of
L-cysteine and glutamate (even on the fact that they act
synergistically).  However, I have not found any studies on the
effects of hydrolysis or other processing technologies on the
quantities of these compounds in food or food supplements.  That is
not to say that such studies do not exist, but they do not seem to be
indexed in Medline.

And Blaylock doesn't appear to have been cited in the Science Citation
Index, at least not in major journals, either.  Are you referring to
his book, or has he written articles on this as well?

Blaylock is not indexed in Medline either in this particular context,
although he does have eight papers listed which date from 1974-1981
and which match his claim: " have published several papers in peer
reviewed journals on a variety of subjects from the pathology and
treatment of pituitary tumors to immunothearpy of brain tumors."
http://www.holisticmed.com/add/blaylock.html
At the same URL is a summary of his theories on excitotoxins in food,
unfortunately without any cited sources, although apparently his book
does cite "well over five hundred scientific studies" to support his
claims (http://www.healthpress.com/excitotoxins.html)

Dear Tehuti and Librariankt, 

Thanks for your good legwork (I've been there and know it takes
more than a trivial effort to find his stuff ) and salient comments. 
(btw, he is working on a second book currently, is on the Editorial
 Board of JANA, and has published a smallish how-to book on anthrax
 prophylaxis; see www.bioterrorismbook.com) 

The "excitotoxicity" of cysteine and glutamate, like the toxicity of
oxygen, operate at/above some minimum level. In other words, about 1 mg/kg
of glutamate on a regular basis is very likely easily handled by the
average American, but 100 mg/kg would certainly not be.  I had hoped
to find some compelling scientific work by someone other than Blaylock
that:

1) Identified the transition zone relative to a given
    individual's size, weight, and antioxidant load, and

2) Explained why the 3g of glumate in my whey protein powder
    is dangerous while the same 3g of glumate (and similar
    for aspartic acid) I'd get from eating two jumbo eggs
    (source: USDA nutrition database) is somehow "ok". 

I have read some comments on how some amino acids are "free"
versus "bound" but it never became clear to me what the definitions
of these are, and how they differ. 

Thanks again for your thoughts and effort, 

~Ross