<<Disclaimer: Verify this information before applying it to your situation.>>

To my fellow celiac and Gluten/wheat intolerant friends:

My original question stemmed from a post on St. Johns Wort and it use in
celiacs. There was a comment that celiacs have more than average serotonin
in the gut. I do not have a direct answer to that yet but since I have so
much related info I though I would send it out for you to ponder.
Since there is so much discussion of depression and its link to celiac I
researched that as well as the whole "serotonin in the gut" theory. here is
what i've come up with so far. Thanks to those who wrote, please feel free
to write if you have more information.

from people on the list:

serotonin in general:
A chemical, 5-hydroxytryptamine (5-HT), present in platelets,
gastrointestinal mucosa, mast cells, and carcinoid tumors.  Serotonin is a
potent vasoconstrictor.  It is also a neurotransmitter in the central
nervous system and is important in sleep-waking cycles.
****
Re:  Oct 27 interview of Dr. Michael Gershon, author of "The SecondBrain:
The Scientific Basis of Gut Instinct." chair of anatomy and cell biology at
Columbia U.

http://cpmcnet.columbia.edu/dept/anatomy/Faculty/Gershon/index.html
Dr. Gershon described the nervous system of the gut.  He took questions
about ulcerative colitis, celiac sprue, GERD, autism, referred pain,
intestinal candida, fibromyalgia among others.  He described the function of
seratonin in the gut and why it worked for some patients - but not those
with auto-immune diseases.
******
the rest of the information I got from the internet
from Medline- http://www.healthy.net/Library/search/medline.htm

DEPRESSION AND CD-
Addolorato G; Stefanini GF; Capristo E; Caputo F; Gasbarrini A;
Gasbarrini G
Address
Institute of Internal Medicine, Universita' Cattolica del Sacro Cuore, Rome.
Source
Hepatogastroenterology, 43(12):1513-7 1996 Nov-Dec
Abstract
BACKGROUND/AIMS: Psychiatric illness and psychological behavioral
pathologies may be present in celiac disease and in IBD patients. In these
subjects anxiety and depression could be a main cause in the reduction of
the compliance to the treatment. Aim of our study was to carry out a
psychometric evaluation using appropriate means to determine the level of
anxiety and depression and to distinguish between "state" and "trait" forms.
The correction of such disturbances would improve the quality of life and
the patients' compliance to treatment. MATERIAL AND METHODS: Sixteen adult
celiac patients, 16 subjects affected by IBD and 16 healthy control subjects
matched for sex, residence and marital status were studied by psychological
assessment. All the subjects were given the State and Trait Anxiety
Inventory and the Ipat Depression Scale Questionnaire. RESULTS: State
anxiety was present in a higher percentage of celiac subjects and in the
patients affected by IBD with respect to the healthy controls. Anxiety as a
trait was present in a similar percentage in all the subjects evaluated.
Depressive syndrome was present in a percentage of celiac patients
statistically superior versus the healthy control group (p < 0.01).
CONCLUSION: Our results shown that anxiety is present as a "reactive" form
and personality trait anxiety has no effect in celiac and IBD patients. As
regard depression, our data confirm a possible linkage between brain
functions and malabsorption

SEROTONIN AND CD:
Platelet serotonin transporter in coeliac disease.
Author
Chiaravalloti G; Marazziti D; Batistini A; Favilli T; Ughi C; Ceccarelli M;
Cassano GB
Address
Institute of Paediatrics, University of Pisa, Italy.
Source
Acta Paediatr, 86(7):696-9 1997 Jul
Abstract
We investigated a peripheral serotonergic marker, I.e. platelet tritiated
imipramine (3H-IMI) binding sites, which are part of the 5-HT transporter
complex similar to that present in the brain, in 20 patients affected by
coeliac disease (CD), as compared with 20 healthy controls. Platelet
membranes and 3H-IMI binding were carried out according to a standardized
protocol. The results showed that coeliac patients had significantly lower
3H-IMI binding sites than controls. This finding would suggest the presence
of a dysfunction at the level of the 5-HT transporter that might underline
the psychic disturbances frequently observed in coeliac patients.

from go ask Alice- http://home.microsoft.com/search/lobby/csearch.asp
Serotonin is a substance that is found in many of the body's tissues,
particularly in blood platelets, the *lining of the digestive tract* and the
brain. In the brain, serotonin acts as a neurotransmitter (a chemical
involved in the transmission of nerve impulses between nerve cells). It is
thought to be involved in controlling states of consciousness and mood,
particularly promoting sleepiness and relaxation.

There is a hypothesis (research results have been conflicting) that meals
rich in simple or complex carbohydrates (sugars and starches) and low in
protein, increase serotonin levels. After consumption of a carbohydrate-rich
meal, insulin is secreted, which causes a lowering of blood levels of most
amino acids (building blocks of protein) with the exception of tryptophan,
which is a precursor to serotonin. When there is high blood tryptophan in
relation to other amino acids, tryptophan enters the brain at a rapid rate,
thus synthesizing serotonin.

An overview of research results indicate that people become tired two hours
following the carbohydrate rich meal, which would be expected if
carbohydrates do in fact increase brain serotonin. What has confused
researchers is that obese, premenstrual and depressed subjects usually
report a temporary lifting of mood and reduction in depression after a
carbohydrate-rich meal. Researchers are still not sure if this is because
serotonin levels do not increase under these conditions or if serotonin is
released but some factor in these three cases causes the serotonin to be
mood elevating rather than relaxing.
****
we don't eat as many carbohydrates or the same types- perhaps this is the
reason???
****
The Inflammation - Depression Connection by Ron Hoggan
www.panix.com/~donwiss/hoggan/inflam.txt
Since untreated celiac disease is typified by a chronic inflammation in the
small intestine (3), and since it has been demonstrated that Gluten, in
those with celiac disease, causes microvascular leakage, as indicated by
fibrinogen release (4), and intestinal bleeding (5), there is good cause to
suspect that celiac-associated depression,  is caused, in part at least, by
serotonin deficiency.

Of course, only about one half of 1% of the population has celiac disease.
That does not explain the broad usage of these SSRIs. Something else might,
though. From 5% to 15% of the population demonstrates antigliadin
antibodies. Is it possible that there a similar dynamic of intestinal
inflammation resulting in serotonin depletion in folks with Gluten
intolerance? Is it also possible that folks with other food intolerances
suffer similar intestinal inflammation, which also depletes serotonin
reserves?
*****
from Alphanutrition www.nutramed.com/digestion/celiac_mechanism.htm
(good site for other info on CD as well)

There are at least four possible mechanisms involved at the bowel level:
Lack of the digestive enzyme, intestinal glutaminase.
Antibody production to the prolamine, or a fragment of it.
Increased permeability of the bowel to macromolecules including the
antigenic protein and its fragments.

Increased production and release of mediators such as histamine, serotonin,
kinins, prostaglandins, interferons and interleukins.
****
I hope this answers at least a few questions. I know it made me ask more but
I am glad to see that people out there are researching and coming up with a
few theories.
-Aimee