An FNB committee established RDAs for vitamin D to indicate daily intakes sufficient to maintain bone health and normal calcium metabolism in healthy people.
RDAs for vitamin D are listed in both micrograms (mcg) and international units (IU); 1 mcg vitamin D is equal to 40 IU.
Even though sunlight is major source of vitamin D for some people, FNB based vitamin D RDAs on assumption that people receive minimal sun exposure .
For infants, FNB committee developed AIs based on amount of vitamin D that maintains serum 25(OH)D levels above 20 ng/mL (50 nmol/L) and supports bone development.
