Omega-3 fatty acids
From Ganfyd
ΕΤΥΜΟΛΟΓΙΑ
The name derives from chemical nomenclature. The first carbon adjacent to the carboxyl group is designated alpha (α) while omega (ω) refers to the very last carbon atom regardless of the length of the carbon chain. Omega-3 in the context of fatty acids refers to the presence of a carbon double-bond at the 3rd carbon from the end. See also Greek alphabet.Omega-3 fatty acids is the popular name for n-3 polyunsaturated fatty acids as found in oily fish. As well as being essential dietary components as they can not be synthesised in man de novo, they can also be used as therapeutic agents, particularly where the diet is deficient.
Non-fish sources include walnuts, pumpkin seeds and flax seeds. This is just as well given dwindling fish stocks although the benefits of supplimenting normal diets may have been over hyped [1]
- Omacor® is a mixture of eicosapentaenoic acid (EPA) ethyl ester 46% and docosahexaenoic acid (DHA) ethyl ester 38% and has been shown to be beneficial in secondary prevention after myocardial infarction in addition to other standard therapy, particularly in the subgroup with heart failure[6] and treating Type IV hypertriglyceridaemia and type IIb/III in combination with statins. It may not be beneficial in those who have an equivalent or large intake of omega-3 fatty acid from the diet. The JELIS trial in Japan that used EPA alone and had a larger postmenopausal female representation than is usual in most cardiovascular trials did not quite reach statistical significance for secondary prevention of major coronary events.[7]
- Despite claims there are wide areas of unknown effectiveness There is little, if any evidence of long term benefit of Omega-3 fatty acids in primary prevention and other secondary prevention despite many studies, with conflicting meta-analysis to this conclusion being believed to be due to use of short term outcome data, confounding issues such as toxicity from other foodchain toxins, and other forms of bias. When all primary and secondary prevention RCTs are combined cardiovascular events are reduced by 8% (not significant at 95% level, although significance can be obtained if the DART-2 trial is removed). Meta-analysis is also powered to detect a change in all cause mortality and this last has consistently not been demonstrated, however the data is manipulated. It seems that short term cardiovascular gain does not translate into major mortality gain or reassuringly mortality loss. [8] Omega-3 fatty acids do little harm at least overall.
- In reducing ventricular arrhythmia in patients with implanted cardiovertor-defibrillators very long chain Omega-3 fatty acids are unlikely to be benefical[9] and indeed in heart failure patients the patients levels of these fatty acids are correlated with risk of ventricular arrhythmia[10].
- In patients on TPN likely to be beneficial as it has been found that the hepatic cholestasis syndrome is reversed by omega-3 fatty acids. Randomised controlled trials are awaited.[11]
- In chronic heart failure likely to be beneficial as 1g/day with a 2% absolute reduction in death at 4 years (number needed to treat 56) [12]
Recommendations:
- NICE (CG67 Lipid modification: NICE guideline June 2008):
- "People should not routinely be recommended to take omega-3 fatty acid supplements for the primary prevention of CVD"
- "In secondary prevention due to the conflicting results of the two studies ... for oily fish consumption / omega 3 fatty acid supplementation and the lack of evidence for patients with peripheral arterial disease or following stroke, ... the recommendations made by the Joint British Societies' guidelines on prevention of CVD in clinical practice should be adopted, which recommends at least two servings of omega-3 fatty acid containing fish per week. ...There was insufficient evidence to recommend omega 3 fatty acid supplementation in patients with angina, peripheral arterial disease or stroke."
- SMC (Note SMC guidelines pre-dated the second major Japanese trial)
- Treatment of hypertriglyceridaemia "Not recommended for use within the NHS in Scotland" SCM Omacor 2002)
- "Acceptable for general use within NHS Scotland as an additional treatment for the secondary prevention of myocardial infarction." (SMC Omacor 2002)
rINN: Omacor
Other Names
Omega-3-acid ethyl esters
Pharmacological Information
Relevant Clinical Literature
RCT with Omacor from Pubmed
Systematic reviews from Pubmed
Other Literature
Please read pharmacological data limitations
References
- ↑ Brunner E. Oily fish and omega 3 fat supplements BMJ, doi:10.1136/bmj.38798.680185.47 (published online 24 March 2006)
- ↑ Hooper L, Thompson RL, Harrison RA, Summerbell CD, Ness AR, Moore HJ, Worthington HV, Durrington PN, Higgins JPT, Capps NE, Riemersma RA, Ebrahim SBJ, Smith GDS. Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review BMJ, doi:10.1136/bmj.38755.366331.2F (published 24 March 2006)
- ↑ Yokoyama M, Origasa H, Matsuzaki M et al. Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients (JELIS): a randomised open-label, blinded endpoint analysis The Lancet 2007 369(9567):1090-98
- ↑ Hooper L, Thompson RL, Harrison RA, Summerbell CD, Ness AR, Moore HJ, Worthington HV, Durrington PN, Higgins JPT, Capps NE, Riemersma RA, Ebrahim SBJ, Smith GDS. Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review BMJ, doi:10.1136/bmj.38755.366331.2F (published 24 March 2006)
- ↑ Yokoyama M, Origasa H, Matsuzaki M et al. Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients (JELIS): a randomised open-label, blinded endpoint analysis The Lancet 2007 369(9567):1090-98
- ↑ Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial. Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto miocardico. Lancet. 1999;354(9177):447-55. Erratum in: Lancet 2001;357(9256):642.
- ↑ Yokoyama M, Origasa H, Matsuzaki M et al. Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients (JELIS): a randomised open-label, blinded endpoint analysis The Lancet 2007 369(9567):1090-98
- ↑ Hooper L, Thompson RL, Harrison RA, Summerbell CD, Ness AR, Moore HJ, Worthington HV, Durrington PN, Higgins JPT, Capps NE, Riemersma RA, Ebrahim SBJ, Smith GDS. Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review BMJ, doi:10.1136/bmj.38755.366331.2F (published 24 March 2006)
- ↑ Brouwer IA, Zock PL, Camm AJ, Bocker D, Hauer RN, Wever EF, Dullemeijer C, Ronden JE, Katan MB, Lubinski A, Buschler H, Schouten EG; SOFA Study Group. Effect of fish oil on ventricular tachyarrhythmia and death in patients with implantable cardioverter defibrillators: the Study on Omega-3 Fatty Acids and Ventricular Arrhythmia (SOFA) randomized trial.JAMA. 2006;295(22):2613-9.
- ↑ Wilhelm M, Tobias R, Asskali F, Kraehner R, Kuly S, Klinghammer L, Boehles H, Daniel WG. Red blood cell omega-3 fatty acids and the risk of ventricular arrhythmias in patients with heart failure. American heart journal. 2008 Jun; 155(6):971-7.(Link to article – subscription may be required.)
- ↑ Gura KM, Duggan CP, Collier SB, Jennings RW, Folkman J, Bistrian BR, et al. Reversal of parenteral nutrition-associated liver disease in two infants with short bowel syndrome using parenteral fish oil: implications for future management. Pediatrics. 2006;118:e197-201.
- ↑ Gissi-Hf Investigators. Effect of n-3 polyunsaturated fatty acids in patients with chronic heart failure (the GISSI-HF trial): a randomised, double-blind, placebo-controlled trial. Lancet. 2008 Aug 29.(Epub ahead of print) (Link to article – subscription may be required.)
