Other factors, such as pregnancy and your health, are also important.Infants (adequate intake of vitamin D)0 - 6 months: 400 IU (10 micrograms (mcg) per day)7 - 12 months: 400 IU (10 mcg/day) Children1 - 3 years: 600 IU (15 mcg/day)4 - 8 years: 600 IU (15 mcg/day) Older children and adults9 - 70 years: 600 IU (15 mcg/day)Adults over 70 years: 800 IU (20 mcg/day)Pregnancy and breast-feeding: 600 IU