Vitamins K2, D3, and A provide clinically relevant doses of the three fat-soluble vitamins essential for optimal bone health. Although necessary for cardiovascular health, blood sugar regulation, immune function, and inflammation control, vitamins A, D3, and K2 have complementary physiological functions related to bone, such as modulating gene expression in osteoblasts and carboxylating osteocalcin, an enzyme required for bone formation. This is illustrated by a reduction in undercarboxylated osteocalcin and an increase in bone mineral density (BMD) in postmenopausal women when vitamin K2 is added to vitamin D3 supplementation.
Vitamin D3 has diverse and important functions in multiple body systems, and widespread deficiency amplifies these crucial roles. Supplementation is associated with a well-established reduction in osteoporotic fractures. Correcting vitamin D3 deficiency is essential when supplementing with vitamin A, as vitamin A appears to promote bone health if vitamin D3 levels are adequate. Vitamin K2 is now recognized as necessary not only for clotting but also for the carboxylation of enzymes essential for bone and blood vessel health. Indeed, a meta-analysis showed improved spinal BMD and reduced fractures in postmenopausal women with osteoporosis, while data from controlled trials show a reduction in age-related BMD decline in healthy postmenopausal women. The MK-7 form of vitamins K2, D3, and A has a longer half-life than any other form.