Vitamin K for Healthy Bones
Vitamin K is a fat-soluble vitamin. Medicine, a decade ago knew Vitamin K as only having a role to play in the blood clotting mechanism. Recently, there is a consistent line of evidence in medical science that clearly demonstrates that vitamin K can improve bone health. The human intervention studies have demonstrated that vitamin K can not only increase bone mineral density in osteoporotic people but also actually reduce fracture rates.
Increased intake of vitamin K, both from diet and supplements, has a significant impact on bone health and “striking” reductions in hip fractures, says a new meta-analysis. Three vitamin-K dependent proteins have been isolated in bone. Osteocalcin is a protein synthesized by osteoblasts (bone forming cells).
The synthesis of osteocalcin by osteoblasts is regulated by the active form of vitamin D, 1,25(OH)2D3 or calcitriol. The mineral-binding capacity of osteocalcin requires vitamin K-dependent gamma-carboxylation of three glutamic acid residues. The function of osteocalcin is unclear, but is thought to be related to bone mineralization. Matrix Gla protein (MGP) has been found in bone, cartilage, and soft tissue, including blood vessels. The results of animal studies suggest MGP prevents the calcification of soft tissue and cartilage, while facilitating normal bone growth and development.
The vitamin K-dependent anticoagulant protein S is also synthesized by osteoblasts, but its role in bone metabolism is unclear. Children with inherited protein S deficiency suffer complications related to increased blood clotting as well as to decreased bone density.