What are the effects of increased intake of fish- and plant-based omega-3 fats (LCn3 and ALA) on all-cause mortality, cardiovascular events, adiposity, and lipids?
Omega-3 EPA/DHA Fish Oil, a meta-analysis in 162,796 participants (Cochrane Database Syst Rev 2020, PMID 32114706) — increasing LCn3 had little or no effect on all-cause mortality (RR 0.97), cardiovascular mortality (RR 0.92), cardiovascular events (RR 0.96), stroke (RR 1.02), or arrhythmia (RR 0.99).
Source: Cochrane Database Syst Rev 2020, PMID 32114706 ↗ · Research map · How Magellan grades evidence · evidence confidence: high
Cochrane Database Syst Rev · 2020 · PMID 32114706 · DOI 10.1002/14651858.CD003177.pub5
Omega-3 supplements (LCn3) may slightly reduce coronary heart disease risk and triglycerides, while plant-based omega-3 (ALA) may slightly reduce overall cardiovascular events and arrhythmia.
The question
What are the effects of increased intake of fish- and plant-based omega-3 fats (LCn3 and ALA) on all-cause mortality, cardiovascular events, adiposity, and lipids?
What they tested
Omega-3 polyunsaturated fatty acids from oily fish (LCn3) and plants (ALA) may benefit cardiovascular health.
How they did it
This systematic review included 86 randomized controlled trials (RCTs) with 162,796 participants, lasting at least 12 months. Trials compared supplementation or advice to increase LCn3 or ALA intake versus usual or lower intake. Data were extracted and validity assessed by two independent reviewers, with separate random-effects meta-analyses for ALA and LCn3 interventions and meta-regression for dose-response relationships.
What they found
Increasing LCn3 had little or no effect on all-cause mortality (RR 0.97), cardiovascular mortality (RR 0.92), cardiovascular events (RR 0.96), stroke (RR 1.02), or arrhythmia (RR 0.99). It may slightly reduce coronary heart disease mortality (RR 0.90, NNTB 334) and coronary heart disease events (RR 0.91, NNTB 167). Increasing ALA intake probably made little or no difference to all-cause mortality (RR 1.01), cardiovascular mortality (RR 0.96), coronary heart disease mortality (RR 0.95), and coronary heart disease events (RR 1.00). Increased ALA may slightly reduce risk of cardiovascular disease events (NNTB 500) and probably slightly reduces risk of arrhythmia (RR 0.73, NNTB 91). Increasing LCn3 reduced triglycerides by approximately 15% in a dose-dependent manner.
What it means
Increasing LCn3 slightly reduces the risk of coronary heart disease mortality and events, and reduces serum triglycerides. Increasing ALA slightly reduces the risk of cardiovascular events and arrhythmia.
Limitations
The certainty of evidence for some outcomes, such as coronary heart disease mortality and events for LCn3, and cardiovascular disease events and arrhythmia for ALA, was low to moderate. Most LCn3 evidence came from supplement trials, and there was little evidence regarding the effects of eating fish.
The paper at a glance
| Magellan’s evidence label | anti-inflammatory long-chain PUFAs (our label for this citation — see PubMed for the paper’s own title and authors) |
|---|---|
| Journal | Cochrane Database Syst Rev |
| Year | 2020 |
| PMID | 32114706 ↗ |
| DOI | 10.1002/14651858.CD003177.pub5 ↗ |
| Topic | Cardiovascular & vascular aging |
Read the source: PubMed record (authors, abstract, full citation) ↗ · Publisher via doi.org ↗
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Omega-3 EPA/DHA Fish Oil
Across large randomized trials and meta-analyses, marine omega-3s reliably reduce serum triglycerides (roughly 15% at higher doses) and modestly lower blood pressure and resting heart rate, but their effect on cardiovascular events is mixed and depends on dose, formulation and population.
Omega-3 fatty acids are long-chain polyunsaturated fats, principally eicosapentaenoic acid (EPA) and…
Research describes the compound or intervention studied. It is not a claim about any specific product.
Molecules & mechanisms in this paper
Each of these is named in the paper’s own words above. Open the monograph for the full mechanism and its other citations.
Cite this page
These citations point at this summary. To cite the original paper with its full author list, use the PubMed record or doi.org.
Magellan Longevity. (2026). What are the effects of increased intake of fish- and plant-based omega-3 fats (LCn3 and ALA) on all-cause mortality, cardiovascular events, adiposity, and lipids? [Plain-English summary of Cochrane Database Syst Rev 2020, PMID 32114706, DOI 10.1002/14651858.CD003177.pub5]. Magellan Longevity. https://magellanlongevity.com/study/s128.html@misc{magellan_s128,
title = {What are the effects of increased intake of fish- and plant-based omega-3 fats (LCn3 and ALA) on all-cause mortality, cardiovascular events, adiposity, and lipids?},
author = {{Magellan Longevity}},
year = {2026},
howpublished = {\url{https://magellanlongevity.com/study/s128.html}},
note = {Plain-English summary of PubMed PMID 32114706; DOI 10.1002/14651858.CD003177.pub5; Cochrane Database Syst Rev 2020. Reviewed by Gabriel Radu, DO},
urldate = {2026-08-11}
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