Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review
Open accessAbstract
OBJECTIVE: To review systematically the evidence for an effect of long chain and shorter chain omega 3 fatty acids on total mortality, cardiovascular events, and cancer. DATA SOURCES: Electronic databases searched to February 2002; authors contacted and bibliographies of randomised controlled trials (RCTs) checked to locate studies. REVIEW METHODS: Review of RCTs of omega 3 intake for (3) 6 months in adults (with or without risk factors for cardiovascular disease) with data on a relevant outcome. Cohort studies that estimated omega 3 intake and related this to clinical outcome during at least 6 months were also included. Application of inclusion criteria, data extraction, and quality assessments were performed independently in duplicate. RESULTS: Of 15,159 titles and abstracts assessed, 48 RCTs (36,913 participants) and 41 cohort studies were analysed. The trial results were inconsistent. The pooled estimate showed no strong evidence of reduced risk of total mortality (relative risk 0.87, 95% confidence interval 0.73 to 1.03) or combined cardiovascular events (0.95, 0.82 to 1.12) in participants taking additional omega 3 fats. The few studies at low risk of bias were more consistent, but they showed no effect of omega 3 on total mortality (0.98, 0.70 to 1.36) or cardiovascular events (1.09, 0.87 to 1.37). When data from the subgroup of studies of long chain omega 3 fats were analysed separately, total mortality (0.86, 0.70 to 1.04; 138 events) and cardiovascular events (0.93, 0.79 to 1.11) were not clearly reduced. Neither RCTs nor cohort studies suggested increased risk of cancer with a higher intake of omega 3 (trials: 1.07, 0.88 to 1.30; cohort studies: 1.02, 0.87 to 1.19), but clinically important harm could not be excluded. CONCLUSION: Long chain and shorter chain omega 3 fats do not have a clear effect on total mortality, combined cardiovascular events, or cancer.
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Other meta-analyses suggest reduced major cardiovascular events in patients with high triglycerides and low HDL cholesterol treated with fibrates, but no decrease in cardiovascular or total mortality.
“Results from other meta-analyses suggest reduced major CVD events in patients with high TGs and low HDL-C in fibrate-treated patients, but no decrease in CVD or total mortality [314-316].”
From 2019 ESC/EAS guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk (2019) · cites this paper as [314]
When end point measures such as cardiovascular disease are taken together in a meta-analysis, the results of omega-3 supplementation are equivocal.
“Yet, when end point measures such as cardiovascular disease are taken together in a meta-analysis the results of omega-3 supplementation are equivocal [40,41,42,43].”
From Omega-3 Fatty Acids and Skeletal Muscle Health (2015) · cites this paper as [40]
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- Authors
- Hooper, L., Thompson, R. L., Harrison, R. A., Summerbell, C. D., Ness, A. R., Moore, H. J., Worthington, H. V., Durrington, P. N., Higgins, J. P. T., Capps, N. E., Riemersma, R. A., Ebrahim, S. B. J., & Smith, G. D.
- Affiliations
- University of East Anglia (GB)
- University of Southampton (GB)
- Teesside University (GB)
- University of Bristol (GB)
- University of Manchester (GB)
- MRC Biostatistics Unit (GB)
- Shrewsbury and Telford Hospital NHS Trust (GB)
- University of Edinburgh (GB)
- London School of Hygiene & Tropical Medicine (GB)
- Corresponding author
- Hooper, Lee
- ORCID
- Venue
- BMJ
- Publisher
- BMJ
- Published
- 2006-03-24
- Volume
- 332
- Issue
- 7544
- Pages
- 752-760
- ISSN
- 0007-1447 (ISSN-L)
- 0959-8138
- 1468-5833
- PMC
- PMC1420708
- OpenAlex
- W2123273468
- Cited by
- 676
- References
- 24
- Citations by year
- 2026: 3 · 2025: 4 · 2024: 7 · 2023: 11 · 2022: 6 · 2021: 13 · 2020: 12 · 2019: 23 · 2018: 26 · 2017: 19 · 2016: 19 · 2015: 35 · 2014: 45 · 2013: 51 · 2012: 44
- FWCI
- 9.97
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- BMJ (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Teesside University Research Portal (Teesside University) (publishedVersion, cc-by-nc-nd)
- Edinburgh Research Explorer (University of Edinburgh) (acceptedVersion, other-oa)
- Durham Research Online (Durham University) (acceptedVersion)
- LSHTM Research Online (London School of Hygiene and Tropical Medicine) (acceptedVersion)
- Durham Research Online (Durham University) (submittedVersion, cc-by)
- TeesRep (Teesside University) (submittedVersion, cc-by-nc-nd)
- HighWire Press Open Archive (submittedVersion)
- Research Explorer (The University of Manchester) (submittedVersion)
- Explore Bristol Research (submittedVersion)
- Bristol Research (University of Bristol) (submittedVersion)
- UEA Digital Repository (University of East Anglia) (submittedVersion)
- Topics
- Health Sciences › Nursing › Nutrition and Dietetics › Fatty Acid Research and Health
- Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Nutritional Studies and Diet
- Physical Sciences › Chemistry › Organic Chemistry › Edible Oils Quality and Analysis
- Keywords
- omega-3 fatty acids, all-cause mortality, cardiovascular events, cancer risk, dietary supplementation, cardiovascular disease prevention
- MeSH terms
- Cardiovascular Diseases, Fish Oils, Humans, Neoplasms, Prognosis, Risk Factors, Cohort Studies, Fatty Acids, Omega-3, Randomized Controlled Trials as Topic, Dietary Supplements
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