Andew MD:
Did the study you quoted assess the adequacy of the breastfeeding?  What were
the babies' weights like/was there milk transfer occuring/etc?  Most studies
do not adequately assess the breastfeeding and control for calorie intake.  I
would worry that adding formula to these infants could undermine the
establishment of adequate lactation/breastfeeding, as well as set up some of
these infants for allergies, etc.
Linda L. Shaw MD FAAP