HI -

I had a discussion with several physicians on this topic.  The consensus
seems to be that breastfeeding is far and away the best thing you can
do for a baby if there's ANY allergy in the family, and that the lactating
mother should go cold turkey on any foods that cause an allergic  reaction
in her child.

Allergy, however, should not be confused with colick.  Many babies will
develop gas and cramps from milk in the mother
s diet, but that particular reaction usually is a digestive issue rather
than an allergy issue, and typically passes between 6 and 12 months of
age.

If a child with allergy  needs to go on formula, then don't fuss with
different brands.  The different categories are milk formula, soy formula,
hypoallergenic formula (which does contain casein, but is okay for a
majority of allergic kidsd) and amin acid formula which is fearfully
expensive and available only by prescription.  (Ask your pediatrician
if this is an issue for you.)

The WHO recommends that children breastfeed until the age of 4; the APA
says until the age of 2 since diarrheic diseases aren't very prevalaent in
the US and the general level of nutrition is better than in devloping
countries.  But in any event, breastfeeding until the age of 4 is socially
awkward but entirely healthful for your child.  And may be a lifesaver if
you've got allergy problems.

I hope I've parroted everything correctly.
--Beth Kevles
  [log in to unmask]
  http://web.mit.edu/kevles/www/nomilk.html -- a page for the milk-allergic

PS - Support for extended breastfeeding can be helpful; try your local
La Leche League if you need moral support, or misc.kids.breastfeeding
on the Internet.