Vitamin D for Cardiovascular Disease
For preventing cardiovascular disease, vitamin D supplements do not work: large, high-quality randomized trials and meta-analyses consistently show no reduction in heart attacks, strokes, or cardiovascular death. Vitamin D remains important for bone and general health, but it is not a tool for protecting the heart.
Why this grade7-layer evidence engine
This earns a Counter-Evidence grade because the negative evidence is unusually mature and consistent, not merely thin. The landmark VITAL trial randomized 25,871 adults to 2,000 IU/day and found no reduction in major cardiovascular events (HR 0.97, 95% CI 0.85-1.12; PMID 31733345). Two large meta-analyses agree: one pooling over 83,000 people across 21 trials showed no effect on major events (RR 1.00, 95% CI 0.95-1.06; PMID 31215980), and another of more than 70,000 people found no benefit for cardiovascular death, stroke, or heart attack (PMID 35956336).
Major clinical authorities reinforce this. The Cleveland Clinic, Harvard Health, and the American Heart Association all state that vitamin D supplements do not lower cardiovascular risk, while the Mayo Clinic cautions that the observed link between low vitamin D and heart disease is a correlation, not proof of cause.
Two caveats matter. Regulators like the FDA, EFSA, and NHS endorse vitamin D, but only as an essential nutrient for bone, immune, and calcium roles, not for heart protection. And high doses, or combined calcium-plus-vitamin-D, may carry harm signals such as vascular calcification and higher stroke risk, so more is not better.
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 = 0.254
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高階證據未達主導 (0 positive vs 1 negative)，由 raw_score 決定
- 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