Omega-3 / Fish Oil for Cholesterol
Omega-3 (fish oil) reliably lowers triglycerides, but it does little for LDL or total cholesterol and over-the-counter supplements have not been shown to improve heart outcomes. Treat it as a targeted triglyceride tool, not a general cholesterol fix.
Why this grade7-layer evidence engine
The B grade reflects a narrow but consistent benefit. Four high-quality 2023-2025 meta-analyses agree that omega-3 meaningfully cuts triglycerides: a coronary-disease analysis found a significant TG drop (SMD -0.25) with only a small change in total cholesterol and none in LDL (PMID 40463990), and a postmenopausal-women analysis showed TG falling by 17.8 mg/dL (PMID 36641259). Regulators and clinics concur on this specific effect, with EFSA citing 2-4 g/day for triglycerides and the AHA noting prescription omega-3 lowers high triglycerides by roughly 20-30%.
The grade stays at preliminary, not high, because the benefit does not extend to cholesterol broadly. The same postmenopausal analysis showed LDL-C actually rising 4.1 mg/dL while total cholesterol was unchanged (PMID 36641259), so 'lowering triglycerides' is not the same as 'lowering cholesterol.' For hard heart outcomes the picture is mixed: omega-3 added to statins reduced events in one pooled analysis of 40,991 patients (PMID 38040215), but another of 29,913 patients found no overall effect on major cardiovascular events, with benefit confined to people who started with high triglycerides (PMID 38161115).
Authoritative opinion is genuinely split, which is why the verdict carries a warning. Mayo Clinic and the AHA back omega-3 for triglycerides, while Cleveland Clinic and Harvard Health are skeptical that over-the-counter fish oil does much for cholesterol or heart health. The practical reality: prescription-strength 4 g/day drives the real triglyceride effect, typical 1 g/day supplements do far less, funding was undisclosed in most trials, and high doses can raise bleeding risk alongside blood thinners.
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 = 0.665
- 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 + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status