Omega-3 / Fish Oil for Cardiovascular Disease
For the general public taking ordinary fish-oil supplements, omega-3s have not been shown to prevent cardiovascular disease. A clear benefit appears only in a narrow high-risk group using prescription-grade purified EPA, and even then the trial evidence is contradictory.
Why this grade7-layer evidence engine
The grade is weak and disputed because the three largest randomized trials flatly disagree. REDUCE-IT (PMID 30415628) found a striking 25% drop in major cardiac events (HR 0.75) but only in patients with high triglycerides and established disease already on statins, using 4 g/day of prescription purified EPA. By contrast, VITAL (PMID 37836519), testing 1 g/day in the general population, showed no benefit for its primary endpoint (HR 0.92), and STRENGTH (PMID 33190147), using a 4 g/day EPA+DHA mix, was stopped for futility (HR 0.99).
Two meta-analyses temper, rather than resolve, the picture. A 149,051-person analysis (PMID 34505026) found only small reductions in CV mortality (RR 0.93) and non-fatal heart attack (RR 0.87) — with EPA-only formulas faring better — while flagging a higher atrial-fibrillation risk (RR 1.26). An updated review (PMID 36378553) likewise found a modest cut in coronary events (RR 0.91) but no stroke benefit.
Regulators and clinics mirror this split. The FDA grants only a qualified claim and EFSA cites 250 mg/day for normal cardiac function, yet the UK NHS steers people toward eating fish rather than capsules. Cleveland Clinic states supplements lower triglycerides but not cardiovascular risk, Harvard Health finds 'no evidence of heart-related benefits,' and even the more permissive AHA calls supplementation only 'reasonable' for secondary prevention — supporting a C, not a stronger grade.
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 = 0.412
- 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 1 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status