title: n-3 Fatty acids from fish or fish-oil supplements, but not alpha-linolenic acid, benefit cardiovascular disease outcomes in primary- and secondary-prevention studies: a systematic review.
abstract: Studies on the relation between dietary n-3 fatty acids (FAs) and cardiovascular disease vary in quality, and the results are inconsistent. A systematic review of the literature on the effects of n-3 FAs (consumed as fish or fish oils rich in eicosapentaenoic acid and docosahexaenoic acid or as alpha-linolenic acid) on cardiovascular disease outcomes and adverse events was conducted. Studies from MEDLINE and other sources that were of > or =1 y in duration and that reported estimates of fish or n-3 FA intakes and cardiovascular disease outcomes were included. Secondary prevention was addressed in 14 randomized controlled trials (RCTs) of fish-oil supplements or of diets high in n-3 FAs and in 1 prospective cohort study. Most trials reported that fish oil significantly reduced all-cause mortality, myocardial infarction, cardiac and sudden death, or stroke. Primary prevention of cardiovascular disease was reported in 1 RCT, in 25 prospective cohort studies, and in 7 case-control studies. No significant effect on overall deaths was reported in 3 RCTs that evaluated the effects of fish oil in patients with implantable cardioverter defibrillators. Most cohort studies reported that fish consumption was associated with lower rates of all-cause mortality and adverse cardiac outcomes. The effects on stroke were inconsistent. Evidence suggests that increased consumption of n-3 FAs from fish or fish-oil supplements, but not of alpha-linolenic acid, reduces the rates of all-cause mortality, cardiac and sudden death, and possibly stroke. The evidence for the benefits of fish oil is stronger in secondary- than in primary-prevention settings. Adverse effects appear to be minor.
authors.affiliation: Tufts-New England Medical Center Evidence-based Practice Center, Institute for Clinical Research and Health Policy Studies, Tufts-New England Medical Center, Boston, MA, USA.
authors.forename: Chenchen
authors.initials: C
authors.lastname: Wang
authors.forename: William S
authors.initials: WS
authors.lastname: Harris
authors.forename: Mei
authors.initials: M
authors.lastname: Chung
authors.forename: Alice H
authors.initials: AH
authors.lastname: Lichtenstein
authors.forename: Ethan M
authors.initials: EM
authors.lastname: Balk
authors.forename: Bruce
authors.initials: B
authors.lastname: Kupelnick
authors.forename: Harmon S
authors.initials: HS
authors.lastname: Jordan
authors.forename: Joseph
authors.initials: J
authors.lastname: Lau
mesh_terms: D002318:Cardiovascular Diseases / Q000378:metabolism / Q000401:mortality* / Q000517:prevention & control*; D016022:Case-Control Studies; D015331:Cohort Studies; D019587:Dietary Supplements; D019317:Evidence-Based Medicine; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D005395:Fish Oils / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D011322:Primary Prevention; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D017747:Seafood; D016896:Treatment Outcome; D017962:alpha-Linolenic Acid / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D017962:alpha-Linolenic Acid