TABLE 1.

Studies of vitamin D concentration of human milk¹

Reference	Country/race	Maternal Vitamin D intake	Time Postpartum	No.	Season	Mean Antirachitic activity, IU/L1
Hollis et al., 1981 (21)	US/white	NSP	1–21 d	5	NSP	25
Hollis et al., 1986 (15)	US/NSP	400 IU/d	14–90 d	51	All	33–68
Ala-Houhala et al. ,1988 (16)	Finland/white	No supplement	8 wk	20	Winter	14 (8–30)
			8 wk	20	Summer	124 (19–332)
Atkinson et al., 1987 (22)	Canada
		400 IU/d	14–21 d2	8	NSP	80 ± 9
		400 IU/d	14–21 d3	9	NSP	60 ± 7
Specker et al., 1985 (14)	US
	White	512 IU/d	NSP	15	All	68
	Black	365 IU/d	NSP	10		35
Hollis et al., 2004 (18)	US
	White (n = 7), black (n = 2)	NSP	28 d	9	All	40.4 ± 3.7
	White (n = 6), black (n = 3)	NSP	28 d	9	All	35.5 ± 3.5
Wagner et al., 2006 (19)	US
	White (n = 6), Hispanic (n = 2), black (n = 2)	273 ± 274 IU/d	28 d	10	All	59.6

¹Values are mean (range) or mean ± SD. Antirachitic activity was calculated from measurement of milk vitamin D and 25-hydroxyvitamin D concentrations and converted to biological activity, from reference data (20,21). NSP, not specified.

²Preterm mothers.

³Term mothers.