Dietary reference values for vitamin K: where are we now?

Abstract

Notes that vitamin K has long been known to be required for blood clotting, and more recent evidence suggests a role in bone mineralization, atherosclerosis, and apoptosis. Guidelines for vitamin K intake were set in 1991; however, the food compositional data and intake levels in the UK were not known and, as such, no dietary reference values were set. Since then, work in the field has progressed enormously, with a provisional food composition database being developed, both in the UK and USA, and a healthy population reference plasma range for K1 has been established in the UK in parallel with detailed estimates of K1 intake. Plasma K1 and the proportion of undercarboxylated prothrombin and osteocalcin have been identified as sensitive functional markers of vitamin K status. Current work on aspects of vitamin K and bone health in the elderly will further assist with the setting of dietary reference values for the future.