Vitamin D and Health

Pregnancy and lactation
2.80 The role of vitamin D during pregnancy and in the formation of the fetal skeleton is not clear. Vitamin
D supplements (10 µg/400 IU per day) are currently recommended during pregnancy to ensure that
the mother and, therefore, the fetus are not deficient in vitamin D and to avoid neonatal
hypovitaminosis (DH, 1991; DH, 1998). Breast milk is not considered to be a significant source of
vitamin D or its metabolites. The reported vitamin D content of breast milk differs across studies
because it varies with the type of milk measured (foremilk or hindmilk 22 ) and the time of day it is
collected. For some breast fed babies, vitamin D and 25(OH)D contained in breast milk could make a
significant contribution to their vitamin D intake since dietary 25(OH)D has been reported to be 5-
times more effective than vitamin D 3 in raising serum 25(OH)D concentration (Cashman et al., 2012)
(see paragraph 5.4). It is also likely that vitamin D is well absorbed from breast milk as fat absorption
is particularly efficient.
2.81 Associations between vitamin D status during pregnancy and lactation on health outcomes in the
mother and baby are considered in chapter 6.
22 At the start of the feed, the milk (foremilk) is relatively low in fat and quenches the baby’s thirst. Later during the feed, the milk (hindmilk)
becomes richer in fat, which provides calories for growth.
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