Vitamin K for Bone Fracture
For preventing bone fractures, vitamin K supplements do not work. The most rigorous trials and meta-analyses find no reliable reduction in fracture risk, and no regulator or major clinic endorses vitamin K for this purpose.
Why this grade7-layer evidence engine
The grade reflects a surrogate-versus-outcome gap. The strongest analysis, an updated meta-analysis of 36 randomized trials (PMID 31076817), reported a benefit for any clinical fracture (OR 0.72) that disappeared once low-risk-of-bias trials were isolated (OR 0.76, 95% CI 0.58-1.01, non-significant), with no effect on vertebral fractures (OR 0.96). Its authors concluded the evidence is insufficient to confirm a fracture benefit.
The apparently positive earlier meta-analyses (PMID 16801507; PMID 25516361) were driven almost entirely by Japanese trials using prescription-grade MK-4 at 45 mg/day, roughly 500 times typical dietary intake and not generalizable to over-the-counter MK-7. The 2006 review (PMID 16801507) was later flagged by a 2018 erratum for methodological concerns. The only Western trial powered for bone outcomes, the ECKO trial of 5 mg/day K1 (PMID 18922041), was null on its primary bone-density endpoints; its lower fracture count (9 vs 20) was an underpowered, hypothesis-generating secondary finding.
Regulators and clinics align with this verdict. EFSA authorizes only a 'maintenance of normal bone' claim at dietary levels, not fracture prevention, and no agency authorizes a fracture-prevention claim. Mayo Clinic, Cleveland Clinic and Harvard all describe the trial evidence as conflicting, and orthopedic and bone-health societies do not endorse vitamin K supplements for preventing fractures, pointing instead to calcium, vitamin D, exercise and approved osteoporosis drugs.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.302
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (2 篇 > 0 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status