Vitamin K, specifically menaquinone (Vitamin K2), has been studied for its role in bone health, including potential benefits in supporting or treating broken bones. Scientific interest arises from Vitamin K2's function in activating osteocalcin, a protein essential for binding calcium in the bone matrix and thus contributing to bone mineralization. Several observational studies and some randomized controlled trials (RCTs) have suggested that adequate Vitamin K intake may be associated with improved bone mineral density and reduced fracture risk, particularly in postmenopausal women and the elderly. However, most of the evidence pertains to bone health maintenance and osteoporosis prevention, rather than direct treatment of acute fractures.

A few small clinical studies have explored Vitamin K2 supplementation in patients with fractures, with mixed results; some show modest benefits in bone healing, while others do not demonstrate significant effects. Meta-analyses indicate that while Vitamin K supplementation (mainly K2) may reduce fracture incidence in some populations, the overall evidence remains insufficient to recommend it as a primary or standard treatment for broken bones. Most treatment guidelines do not currently include Vitamin K2 for fracture repair.

In summary, there is a plausible biological mechanism and some supportive data for Vitamin K2 in bone health, but the direct evidence for its use in treating broken bones is limited and not robust. Further large, well-designed clinical trials are needed to establish its efficacy in this specific context.