The OK Daily Study is a multi-centred, part-randomised, part blinded, four cohort study. We are exploring daily dietary supplementation with vitamin K2, specifically menaquinone-7 (MK-7), given to breastfed infants or breastfeeding mothers to see whether this improves the incidence of biochemical vitamin K deficiency in the infants at 2 months postnatal age.
The overall aims are:
* To compare infant MK-7 supplementation with placebo
* To compare maternal MK-7 supplementation with placebo
* To compare infant MK-7 supplementation and maternal MK-7 supplementation
* To compare infant MK-7 supplementation with vitamin K1 supplementation via infant formula milk.
Once recruited, mother and infant pairs will be grouped initially based on the families' feeding choice. Breastfed infants will then be randomised 2:1 to the infant supplementation or maternal supplementation group. Within the infant supplementation group, infants will either receive MK-7 with vitamin D or a placebo containing vitamin D.
Follow up will occur at 2 months postnatal age (range 2-3 months postnatal age), where bloods and breastmilk samples will be collected to assess the infant and maternal vitamin K status.