Infants and children: 400 IU Adults under 50: 400-800 IU
Adults over 50: 800 -1,000 IU
(IU = International units)
* People at high risk of vitamin D deficiency, such as those who are bedridden or have osteoporosis or absorption problems, may need significantly more.
SOURCES: American Academy of Pediatrics, National Osteoporosis Foundation, International Osteoporosis Foundation