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Fish Oil and Heart Health after Myocardial Infarction
At the Department of Medicine, University of Tromso, Norway a study which concluded in 1998 and published that same year on MEDLINE. This study’s principal investigator was A. Nordoy. This study looked at the benefits of fish oils on cardiovascular disease. And came up as a major discussion at the European Society for Clinical Investigation.
An expert round table discussion on the relationship between intake of n-3 polyunsaturated fatty acids (PUFA, found in common fish) mainly of fish and other marine sources and coronary heart disease at the came to these following conclusions. Consumption of 1-2 fish meals/wk is associated with reduced coronary heart disease (CHD) mortality. Patients who have experienced myocardial infarction have decreased risk of total, cardiovascular, coronary, and sudden death by drug treatment with 1 g/d of ethylesters of n-3 PUFA, mainly as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The effect is present irrespective of high or low traditional fish intake or simultaneous intake of other drugs for secondary CHD prevention. n-3 PUFA may also be given as fatty fish or triglyceride concentrates.
Patients who have experienced coronary artery bypass surgery with venous grafts may reduce graft occlusion rates by administration of 4 g/d of n-3 PUFA. Patients with moderate hypertension may reduce blood pressure by administration of 4 g/d of n-3 PUFA. After heart transplantation, 4 g/d of n-3 PUFA may protect against the development of hypertension. Patients with dyslipidemia and or postprandial hyperlipemia may reduce their coronary risk profile by administration of 1-4 g/d of marine n-3 PUFA. The combination with statins seems to be a potent alternative in these patients.
There is growing evidence that daily intake of up to 1 energy% of nutrients from plant n-3 PUFA (alpha-linolenic acid) may decrease the risk for myocardial infarction and death in patients with CHD. The objectives for the researchers and experts were to determine scientifically sound conclusions on the effects of fish and fish oils in the diet and the administration of marine n-3 PUFA, mainly eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), and eventually of plant n-3 PUFA, alpha-linolenic acid (ALA, 18:3n-3), on the primary and secondary prevention of CHD.
They concluded, fish in the diet should be considered as part of a healthy diet low in saturated fats for everybody, whereas additional administration of n-3 PUFA concentrates could be given to specific groups of patients.
Omega 3 Fatty Acids and Cardiovascular Disease
William S Harris, Mei Chung, Alice H Lichtenstein, Ethan M Balk, Bruce Kupelnick, Harmon S Jordan and Joseph Lau reviewed a several studies, n–3 Fatty acids from fish or fish-oil supplements, but not linolenic acid, benefit cardiovascular disease outcomes in primary- and secondary-prevention studies.
The researchers felt that the 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 -linolenic acid) on cardiovascular disease outcomes and adverse events was conducted. Studies from MEDLINE and other sources that were of greater than 1 year 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 of the 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 very inconsistent. Evidence suggests that increased consumption of n–3 FAs from fish or fish-oil supplements, but not of -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 the secondary than it is in the primary-prevention settings. Majority of the adverse effects appear to be minor. This study review was published in JAMA on October 18, 2003.
Fish Oil’s Potential to Suppress Fatal Arrhythmias
Jan L Breslow's study, called n–3 Fatty acids and cardiovascular disease, has yet to be published. The research was conducted at The Rockefeller University in New York, New York. The results of prospective cohort studies indicate that consuming fish or fish oil containing the n–3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is associated with decreased cardiovascular death, whereas consumption of the vegetable oil–derived n–3 fatty acid -linolenic acid is not as effective.
Randomized control trials (RCTs) in the context of secondary prevention also indicate that the consumption of EPA plus DHA is protective at doses less than 1 g/d. The therapeutic effect appears to be due to suppression of fatal arrhythmias rather than stabilization of atherosclerotic plaques. At doses greater than 3 g/d, EPA plus DHA can improve cardiovascular disease risk factors, including decreasing plasma triacylglycerols, blood pressure, platelet aggregation, and inflammation, while improving vascular reactivity.
Mainly on the basis of the results of RCTs, the American Heart Association
recommends that everyone eat oily fish twice per week and
that those with coronary heart disease eat 1 g/d of EPA plus DHA from oily fish
or supplements. Directions for future research include:
1) RCTs to confirm the initial trials showing that EPA plus DHA
decreases cardiovascular death and additional studies to determine whether
this effect is due to EPA, DHA, or the combination; the dosage of the effective
components; and whether the mechanism of action in humans is prevention of
fatal arrhythmias.
2) Clinical studies to determine whether the reduction in cardiovascular
disease risk factors is due to EPA, DHA, or the combination and the dosage
of the effective components.
3) Clinical studies to determine whether vegetable oil–derived -linolenic acid added to a diet enriched in n–6 fatty acids can effectively substitute for fish oil–derived EPA plus DHA.
Benefits of Fish Oil in Cardiovascular Disease
The American Journal of Clinical Nutrition published a study in October 2001. The study was called Biochemical effects of a diet containing foods enriched with n-3 fatty acids. The researcher team was made up of 6 scientists: Evangeline Mantzioris, Leslie G Cleland, Robert A Gibson, Mark A Neumann, Maryanne Demasi and Michael J James, from the Rheumatology Unit, Royal Adelaide Hospital, Adelaide, Australia, and the Child Nutrition Research Centre, Flinders Medical Centre, Bedford Park, Australia.
The background of the study was from the results of many studies indicating that consumption of n-3 fatty acids can benefit persons with cardiovascular disease and rheumatoid arthritis. However, encapsulated fish oil is unlikely to be suited to lifetime daily use and recommendations to increase fish intake have not been effective. The objective was to examine the effectiveness of a diet that incorporates foods rich in n-3 fatty acids in elevating tissue concentrations of eicosapentaenoic acid and in suppressing the production of inflammatory mediators.
Healthy male volunteers were provided with foods that were enriched in -linolenic acid (cooking oil, margarine, salad dressing, and mayonnaise) and eicosapentaenoic and docosahexaenoic acids (sausages and savory dip) and with foods naturally rich in n-3 fatty acids, such as flaxseed meal and fish. Subjects incorporated these products into their food at home for 4 weeks.
Fatty acid intakes, cellular and plasma fatty acid concentrations, and monocyte-derived eicosanoid and cytokine production were measured. Analyses of dietary records indicated that intake of eicosapentaenoic acid plus docosahexaenoic acid averaged 1.8 g per day and intake of -linolenic acid averaged 9.0 g per day. These intakes led to an average 3-fold increase in eicosapentaenoic acid in plasma, platelet, and mononuclear cell phospholipids. Thromboxane B2, prostaglandin E2, and interleukin 1ß synthesis decreased by 36%, 26%, and 20% (P < 0.05), respectively.
The researchers conclusions were foods that are strategically or naturally enriched in n-3 fatty acids can be used to achieve desired biochemical effects without the ingestion of supplements or a change in dietary habits. A wide range of n-3-enriched foods could be developed to support large-scale programs on the basis of the therapeutic and disease-preventive effects of n-3 fatty acids. | | |
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For free friendly advice or to order over the phone with a card call: 01772 883950
Omega 3 fish oils Pure EPA is available exclusively from mind 1st.
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