Calcium for Hypertension
Calcium supplements produce only a small, clinically minor drop in blood pressure and are not a treatment for high blood pressure; the strong calcium evidence applies to a different situation (preventing pre-eclampsia in pregnancy), not general adult hypertension.
Why this grade7-layer evidence engine
Pooled randomized data are consistent but the effect is too small to matter clinically. A 2022 Cochrane review (PMID 35014026, 18 trials, 3,140 people) found calcium lowered systolic pressure by only about 1.4 mmHg, and a 2006 meta-analysis (PMID 16673011, 40 trials) found roughly 1.9 mmHg, with diastolic effects often negligible. A 2006 review focused on people who already had hypertension (PMID 16625609) reported about a 2.5 mmHg systolic drop but concluded the causal evidence was weak and probably biased.
The benefit is concentrated in narrow subgroups, not the general patient. Reductions were largest in younger adults and in people with low baseline calcium intake (under about 800 mg/day), so calcium does not behave like a reliable blood-pressure treatment for the broader hypertensive population.
Health authorities back this cautious grade. The FDA endorses calcium only for bone health, the UK NHS advises getting calcium from a balanced diet rather than supplements, and the Mayo Clinic notes that large calcium doses can interact with certain blood-pressure drugs (milk-alkali risk with thiazide diuretics). The genuinely strong evidence (PMID 30277579, pre-eclampsia prevention in low-calcium pregnant women) is a separate indication and should not be read as support for treating ordinary high blood pressure.
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 = 0.485
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (3 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