Vitamin K for Osteoporosis
Vitamin K (mainly K2) shows a modest, inconsistent benefit for spine bone mineral density in postmenopausal adults, but it has not been shown to reliably prevent fractures and is not part of standard osteoporosis treatment. Treat it as supportive of general bone maintenance at best, not a substitute for proven therapies.
Why this grade7-layer evidence engine
This earns a preliminary B because the evidence is split between a soft surrogate marker and the outcome that actually matters. Meta-analyses (PMID 31076817, n=8,762; PMID 37661104, n=1,290) and an MK-7 RCT (PMID 23525894, n=244) show vitamin K modestly slows the decline in lumbar-spine bone mineral density, but the effect at the hip and femoral neck is non-significant and heterogeneity is high. Bone density is only a stand-in for what patients care about: broken bones.
On fractures the picture is much weaker. The one meta-analysis reporting large fracture reductions (PMID 16801507, n=6,759) was driven almost entirely by Japanese trials using prescription-grade MK-4 at 45 mg/day, with high heterogeneity and small-study bias. When those trials are excluded, the updated meta-analysis (PMID 31076817) found no convincing fracture benefit, and the large ECKO trial of K1 5 mg/day (PMID 18922041, n=440) showed no effect on bone density. Everyday over-the-counter K1/MK-7 doses are far lower and cannot be assumed to match those Japanese prescription results.
Regulators and clinicians reflect this caution. EFSA recognizes vitamin K only for maintenance of normal bone, not osteoporosis treatment or fracture prevention; the NHS says a balanced diet supplies enough. Mayo Clinic, Cleveland Clinic, and Harvard all call the bone evidence early or conflicting, and the AACE osteoporosis algorithm omits vitamin K entirely, recommending exercise, calcium, vitamin D, and proven medications. Safety note: vitamin K antagonizes warfarin, so anyone on anticoagulants should keep intake stable and consult a clinician before supplementing.
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 = 0.588
- 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 > 1 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