tions consistent with an EAR-type value of approximately 40 nmol/L below which negative fetal skeletal outcomes were reported (Viljakainen et al., 2010), and another reports an RDA-type value of 50 nmol/L late in gestation above which reduced skeletal BMC was not seen in offspring at 9 years of age (Javaid et al., 2006). In addition, development of the fetal skeleton without dependence on maternal vitamin D is also biologically plausible as indicated by the studies in animal models in rats, mice, pigs, and sheep (see review in Chapter 3). Finally, there is no evidence that the vitamin D requirements of pregnant adolescents differ from those of non-pregnant adolescents.
The EAR is thus 400 IU of vitamin D per day for pregnant women and adolescents. Likewise, the RDA values for non-pregnant women and adolescents are applicable, providing an RDA of 600 IU/day for each group.
Lactation The EAR for non-lactating women and adolescents is appropriate for lactating women and adolescents based on evidence from RCTs (Rothberg et al., 1982; Ala-Houhala, 1985; Ala-Houhala et al., 1988; Kalkwarf et al., 1996; Hollis and Wagner, 2004; Basile et al., 2006; Wagner et al., 2006; Saadi et al., 2007), which are consistent with observational data (Cancela et al., 1986; Okonofua et al., 1987; Takeuchi et al., 1989; Kent et al., 1990; Alfaham et al., 1995; Sowers et al., 1998) that increased maternal vitamin D intakes increase maternal serum 25OHD levels, with no effect on the neonatal serum 25OHD levels of breast-fed infants unless the maternal intake of vitamin D is extremely high (i.e., 4,000 to 6,400 IU/day) (Wagner et al., 2006). Observational studies report no relationship between maternal serum 25OHD levels and BMD (Ghannam et al., 1999) or breast milk calcium content (Prentice et al., 1997). Also, there is no evidence that lactating adolescents require any more vitamin D or higher serum 25OHD levels than non-lactating adolescents. The EAR is thus 400 IU of vitamin D per day for lactating women and adolescents. Likewise, the RDA values for non-lactating women and adolescents are applicable, providing an RDA of 600 IU/day for each group.
Abrams, S. A., K. C. Copeland, S. K. Gunn, J. E. Stuff, L. L. Clarke and K. J. Ellis. 1999. Calcium absorption and kinetics are similar in 7- and 8-year-old Mexican-American and Caucasian girls despite hormonal differences. Journal of Nutrition 129(3): 666-71.
Abrams, S. A. 2006. Building bones in babies: can and should we exceed the human milk-fed infant’s rate of bone calcium accretion? Nutrition Reviews 64(11): 487-94.
Abrams, S. A., P. D. Hicks and K. M. Hawthorne. 2009. Higher serum 25-hydroxyvitamin D levels in school-age children are inconsistently associated with increased calcium absorption. Journal of Clinical Endocrinology and Metabolism 94(7): 2421-7.