Vitamin K is traditionally recognised for its essential role in the activation of clotting factors, yet its function extends far beyond haemostasis. In recent years, increasing attention has been given to its involvement in bone metabolism, particularly through its interaction with vitamin K-dependent proteins (VKDPs). To date, 17 VKDPs have been identified in humans, with functions spanning coagulation, bone health, and vascular biology. Among these, osteocalcin has emerged as a key player in skeletal development and mineralisation. Synthesised by osteoblasts, osteocalcin requires vitamin K-mediated γ-carboxylation to bind calcium and integrate effectively into the bone matrix. Despite this well-established biochemical pathway, the physiological role of osteocalcin remains incompletely understood, with increasing evidence also depicting its influence on energy metabolism and endocrine function.
The complexity of the vitamin K–osteocalcin relationship has led to ongoing debate and investigation. While human studies have provided knowledge, research in animal models offers unique opportunities to also explore this axis. Equine research, in particular, has contributed valuable insights into vitamin K status, VKDP expression, and the potential implications for neonatal development and bone health. Importantly, human research has also uncovered and explored the role of vitamin K in osteoporosis and vascular calcification, highlighting its significance in calcium homeostasis and its potential to mitigate age-related degenerative conditions.
This presentation will explore the current understanding of vitamin K and osteocalcin, drawing on findings from equine research to examine broader implications for bone health between species. The talk will consider the biochemical mechanisms underpinning osteocalcin activation, the challenges in assessing vitamin K status, and the potential consequences of deficiency or suboptimal intake.
By examining the enigma that is osteocalcin—its regulation, function, and broader physiological roles—this presentation aims to stimulate discussion around the significance of micronutrient interactions in bone biology. The findings presented may inform future research directions and contribute to a more nuanced understanding of vitamin K’s role in health and disease.