At 12:28 PM 4/19/97 -0400, you wrote:
>My other son who can't have milk, can't have pineapples.  Is there
>milk proteins or anything in them??
        Since I was a VERY small child (I'm in my 30's now) I've had the
same problem--casein allergy and an extreme allergy to pineapples.  Just a
tiny amount of pineapple juice hidden in any thing makes my throat start to
close within seconds. Pineapple is a fruit and therefore doesn't have very
much protein at all in it (just a trace).  The difference is in the
digestion.  If your son is allergic to dairy proteins, like I think you are
saying he is, his problem is "sort" of a digestive one.
        In the average person, when any source of protein is consumed, it is
broken down BEFORE entering the blood stream into smaller parts known as
amino acids.  These amino acids, the building blocks of all proteins, are
used by the cells in our bodies for various things.  The problem is when
proteins are broken down small enough to enter the blood stream but not
small enough to be in the form of amino acids.  These forms of proteins are
called peptides--which are smaller than protein but larger than amino acids.
The presence of peptides in the blood stream, from my understanding and
study of this, is what causes the allergic reaction to casein.  The immune
system literally views the peptides as an invader in the system and
attacks---the body doesn't see the peptides as "food" or "useful."  This is
where all of the problems occur that we are used to labeling "allergic"
response.
        In the case of pineapple:  it is a VERY rare fruit that contains an
enzyme called bromelain.  Bromelain is an enzyme that is rather rare.
Bromelain breaks down protein.  For this reason, bromelain is USED to treat
some protein allergies. (I believe there are people on this list who take a
commercial form of bromelain as a digestive aid who might speak on this
topic?) This effect of breaking down protein can be viewed by placing fresh
pineapple in yogurt or gelatin--it will go "bad" in a hurry! (Once boiled,
the bromelain in pineapples is inactive--so canned pineapples theoretically
won't produce this effect.) I've studied the chemistry of bromelain (since
it is SO unique) trying to determine if that what was causing the allergic
reaction I have to pineapples but I haven't found the answer yet to that
question.  I suspect it is, since the rest of the content of a pineapple
isn't very different from other fruits I can eat--except for the bromelain.
        Btw, THANK YOU for posting the fact that your son is also allergic
to pineapples.  It was my first allergic response and since that time I've
NEVER met anyone else who had a similar response to the fruit.  While I'm
sorry to know the suffering of any allergies, it is nice to know we aren't
alone! :)