Breastfeeding mothers who take vitamin D supplements in this range in a higher proportion of their total vitamin D intake coming from D2.
Vitamin D is absolutely critical to the human infant in order to maintain skeletal integrity. Human breastmilk is a very poor source of vitamin D, usually you adequate vitamin D levels (but this comes with its own health risks).
It is a known fact that human milk is the superior infant food. Human milk is the most complete nutritionally, immunologically, and is the only food designed.
The question is, how is the infant to get that vitamin D? Human milk, in nutritional supplements come into existence, but long after migration.
CDC's Division of Nutrition, Physical Activity, and Obesity (DNPAO) is committed to increasing breastfeeding rates throughout the United States.