Dietary reference values for vitamin K

Abstract

Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) derives dietary reference values (DRVs) for vitamin K. In this Opinion, the Panel considers vitamin K to comprise both phylloquinone and menaquinones. The Panel considers that none of the biomarkers of vitamin K intake or status is suitable by itself to derive DRVs for vitamin K. Several health outcomes possibly associated with vitamin K intake were also considered but data could not be used to establish DRVs. The Panel considers that average requirements and population reference intakes for vitamin K cannot be derived for adults, infants and children, and therefore sets adequate intakes (AIs). The Panel considers that available evidence on occurrence, absorption, function and content in the body or organs of menaquinones is insufficient, and, therefore, sets AIs for phylloquinone only. Having assessed additional evidence available since 1993 in particular related to biomarkers, intake data and the factorial approach, which all are associated with considerable uncertainties, the Panel maintains the reference value proposed by the Scientific Committee for Food (SCF) in 1993. An AI of 1 μg phylloquinone/kg body weight per day is set for all age and sex population groups. Considering the respective reference body weights, AIs for phylloquinone are set at 70 μg/day for all adults including pregnant and lactating women, at 10 μg/day for infants aged 7-11 months, and between 12 μg/day for children aged 1-3 years and 65 μg/day for children aged 15-17 years.

Keywords: Adequate Intake; Dietary Reference Value; menaquinones; phylloquinone; vitamin K.

Figure 1

Chemical structures of vitamin K and metabolites

1. Molecular masses – Phylloquinone: 450.7 g/mol; MK‐4: 444.7 g/mol; MK‐7: 648.9 g/mol; 5C‐metabolite: 272.3 g/mol; 7C‐metabolite: 298.3 g/mol (see above).

Figure 2

Metabolism of vitamin K in adults

1. K1: phylloquinone; K2: MK‐n: menaquinones. Absorption of menaquinones synthesised from gut microbiota in the large intestine remains uncertain (hence the question mark in the figure) (Section 2.3.1).