The OK Daily Study
Research type
Research Study
Full title
Oral vitamin K2 (menaquinone 7; MK-7) supplementation and effect on vitamin K status of breastfed term infants in early infancy; a four-cohort prospective, part-randomised, part-blinded trial.
IRAS ID
354985
Contact name
Paul Clarke
Contact email
Sponsor organisation
Norfolk and Norwich University Hospitals NHS Foundation Trust
Clinicaltrials.gov Identifier
Clinicaltrials.gov Identifier
TBC, TBC
Duration of Study in the UK
2 years, 4 months, 30 days
Research summary
Babies are born with low vitamin K stores. Without extra vitamin K, this can lead to a condition called vitamin K deficiency bleeding (VKDB). Babies with VKDB bleed spontaneously and up to 60% of babies with late-onset VKDB have a large brain bleed causing brain damage or death. VKDB is largely preventable with the nationally recommended vitamin K booster at birth and enough ongoing vitamin K in the diet.
Most babies with late VKDB are breastfed. Breastfed babies can develop low vitamin K stores despite the vitamin K booster at birth. Breastmilk contains up to 80 times less vitamin K than adequately supplemented infant formula milks, suggesting breastfed babies need more dietary vitamin K. We want to see if giving daily oral vitamin K2 (menaquinone-7) to babies or breastfeeding mothers improves babies’ vitamin K stores.
Recruited babies will be grouped based on their parents’ feeding choice. Formula fed babies are already adequately supplemented with vitamin K1, so do not need any additional supplementation.
Breastfeeding babies will be randomly put into one of 2 groups:
o Infant Supplement Group (double blinded): infants will get either vitamin K2 and vitamin D drops (treatment) or only vitamin D drops ('control')
o Maternal Supplement Group: mothers will get vitamin K2 capsules. Their babies will get vitamin D drops.A single in-person follow up visit will occur when baby is 2 months old (range 2-3 months). 3-4 mL blood (just over half a teaspoon) will be taken from all babies to measure their vitamin K stores. We will also look at maternal vitamin K status and breastmilk vitamin K levels by taking 6 mL of blood and 2.5-5 mL of breastmilk from supplemented mothers and a group of unsupplemented breastfeeding mothers for comparison.
After the 2 month follow up visit, participants will have completed the study.
REC name
London - Riverside Research Ethics Committee
REC reference
26/LO/0296
Date of REC Opinion
20 Apr 2026
REC opinion
Favourable Opinion