Vitamin K₁ has a key role in blood coagulation, bone metabolism and the regulation of calcification^{( 1 )}. There are currently insufficient data available to set an average requirement for vitamin K₁ for children however the European Food Safety Authority (EFSA) has recently proposed an Adequate Intake (AI) of 1·0 µg/kg bodyweight per day based on observed intakes^{( 1 )}. Few data are available on vitamin K₁ intakes in young children. The objective of this analysis was to estimate the intake and sources of vitamin K₁ in Irish pre-school children aged 1–4 years (n = 500) using data from the Irish National Pre-School Nutrition Survey (2010–2011) (www.iuna.net). Dietary intake data were collected using a 4d weighed food record and the vitamin K₁ content of foods was primarily determined using data from the UK food composition tables (COFID)^{( 2 )}. For certain foods where vitamin K₁ values were not available in COFID, the US^{( 3 )} and Danish food composition tables^{( 4 )} and published papers were used to assign suitable vitamin K₁ values. The vitamin K₁ content of composite dishes and retail products were calculated based on their ingredients. Usual intakes of vitamin K₁ were calculated via the NCI-method⁽ Reference Tooze, Kipnis and Buckman ^{5 )} using SAS Enterprise Guide. Body weight (kg) was measured in the participants’ homes by trained researchers. Differences in vitamin K₁ intakes were assessed using a Kruskal-Wallis test (for non-normal data) and a Wilcoxon two sample test was used for post-hoc analysis. The mean daily intakes of vitamin K₁ were 33, 30, 28 and 32 µg for 1, 2, 3 and 4 year olds, respectively. Adjusted for bodyweight, intakes (μg/kg/d) were 2·9, 2·1, 1·8 and 1·8 respectively showing a decrease (p < 0·001) with increasing age from age 1y to 3–4y respectively. Approximately 82 % of children had intakes above the AI of 1·0 µg/kg bodyweight per day. The table below reports the contribution (%) of food groups to vitamin K₁ intake in Irish children aged 1–4 years, by age.

The main source of vitamin K₁ for all ages was ‘vegetable and vegetable dishes’ (24–32 %, range across age), of which 13–20 % came from green vegetables. Other important sources were fruit & fruit juices (15–17 %), meat (10–11 %) and milk (6–25 %). The contribution from milk decreased significantly (p < 0·001) with increasing age from age 1y to age 3–4y primarily due to consumption of fortified infant and child formula in the earlier years^{( 6 )}. Overall, these findings suggest that intakes of vitamin K₁ are adequate for Irish pre-school children.

This research was funded by the Department of Agriculture, Food and the Marine under the project ‘Development of biofortification approaches for enhanced vitamin K content of foods (15/F/670)’