This is not true, and there is no reason to believe it.  However, it
is better advice than take the baby off breast and give lactose free
formula which is what pediatricians in this area generally say.

But as one of my mentors said:  Women with breastfeeding colicky
babies should drink wine until the baby is asleep or the mothers don't
care that the babies are crying.

Jack Newman, MD, FRCPC (not trying to reopen the alcohol debate)