Elisa - my sympathies!  We have a couple of doctors who prescribe Isomil for
healthy babies with "lactose-intolerance" - and the medical aid societies
reimburse parents 50% of the cost of of it too!  Maddening.

The supplement to Vol 67, 1989 of the Bulletin of the WHO, "Infant Feeding,
the Physiological Basis" has a couple of good sections (pages 27 - 28, and
pages 41 - 42) on lactose (the importance of this sugar for human babies),
and lactose intolerance - (different types including how rare primary
lactose intolerance is (1 in 20 000 to 1 in 200 000 births) and
"lactose-intolerance colic" which can be resolved by a simple change in
breastfeeding management).  There's a good long list of references to
support the excellent information these sections contain.  Hope this helps.

Pamela, Zimbabwe