Clinical recommendation	Evidence rating	References	Comments
Infants ingesting less than 1 L (33.8 fl oz) of formula per day, as well as all breastfed or partially breastfed infants, should receive 400 IU of supplemental vitamin D daily.	C	13, 19, 20	Based on disease-oriented evidence and expert opinion
Children and adolescents consuming less than 1 L of vitamin D–fortified milk per day should receive 400 IU of supplemental vitamin D daily.	C	21, 22	Based on disease-oriented evidence and case series
Limiting sunlight exposure may predispose children to vitamin D deficiency.	C	23, 25–27	Based on disease-oriented evidence and expert opinion
The best available biomarker of vitamin D status is serum 25-hydroxyvitamin D levels.	C	28, 29	Based on consensus and disease-oriented evidence
Children at increased risk of vitamin D deficiency may require higher dosages of supplemental vitamin D.	C	32–34	Based on disease-oriented evidence and expert opinion