IBD is Inflammatory Bowel Disease, and has two major forms:  Ulcerative
Colitis and Crohn's Disease.  They are not syndromes or intolerances
(although often found in the company of lactose intolerance, as in my
case) but auto-immune diseases, the same category as Multiple Sclerosis,
and Rheumatoid Arthritis.  Essentially, the immune system attacks the
body itself.  In IBD, the main area of attack is the GI tract.  In UC,
only the colon is involved; in Crohn's the entire tract, from mouth to
rectum, is theoretically affected.  Most often the small intestine is the
focus of Crohn's, but there are many cases, like mine, in which Crohn's
affects the colon only, and from the patient's POV is just like UC.   The
exact causes and mechanisms are not really known.  Arthritis and skin
inflammations commonly appear in IBD patients as collateral disorders.
Naturally, there is no known cure, except surgical removal of the colon
for UC patients.  I have a relatively mild case, and keep it under
moderate control by a particular medicine taken daily, and severe diet
restrictions:  no fruits, no vegetables, no dairy, nothing with grease or
fat.  That's the main taboos.  Essentially, my GI tract can not handle
insoluble fiber in any amount, soluble fiber in only minimal amounts, and
grease/oil/fat in only minute amounts.  The dairy is verboten because of
the lactose intolerance I developed along with the IBD.  If I wander off
this regimen in any way, I quickly develop diarrhea and intense cramps.
Hence I am, in my way, very picky about what I eat and drink. (Oh, did I
mention nothing carbonated for drinks?)
IBD is very quirky:  one patient can tolerate foods that others can eat
only in limited amounts, and still others not at all.  And of course,
some IBDers are willing to put up with diarrhea etc. where others, like
myself, will do everything possible to avoid it.
You have,I take it gluten intolerance:  not colitis.

  Jeffrey Smith       [log in to unmask]
As the lily among thorns is tinged with red and white, so the Community
of Israel is visited now with justice and now with mercy; as the lily
possesses thirteen leaves, so the Community of Israel is vouchsafed
thirteen categories of mercy which surround it on every side.--Zohar