Breastfed infants may get enough vitamin D (provided mom gets 6400 IU)
Breastfed infants may get enough vitamin D in mothers’ milk Reuters Oct 2015
"As an alternative to giving infants daily vitamin D drops, researchers gave mothers different doses of the supplement ranging from 400 to 6,400 IU daily. When women took the highest dose, their breastfed babies received vitamin D levels in breast milk that were similar to the amount provided by the infant drops."
See study in VitaminDWiki