by Craig Weatherby
Last week, news headlines announced clinical trial results that seem likely to confuse many people.
In fact, they represent a kind of red herring... that is, a clue that misleads or distracts the reader.
The news concerned a year-long clinical trial in people who’d just suffered their first heart attack.
The authors of the German study found that when heart attack survivors took fish oil for one year in addition to “optimal” conventional therapy - surgery followed by daily doses of several cardiac drugs - they did not enjoy reduced risks of a second heart attack, stroke, or death within one year.
However, three prior clinical trials of similar design showed that supplemental fish oil can cut substantially reduce the risk of heart-related death … especially the most common, heart-beat related kind, called “sudden cardiac death.” (Lee JH et al. 2008)
The largest previous clinical trial (GISSI-Prevenzione) - which involved 11,000 participants taking standard cardiac drugs plus fish oil - found a huge 40 percent reduction in sudden cardiac deaths, versus drug therapy alone.
Those results which match those of a major statin drug trial, suggest that omega-3s can be as effective as those common drugs (Marchioli R et al. 2001; Marchioli R et al. 2007; Tonkin AM et al. 2006).
In fact, the overwhelming majority of evidence supports the current medical consensus, which holds that omega-3-rich diets help protect cardiac health… and reduce the risk of dying from cardiovascular disease (CVD).
When the scientists who co-authored the current American Heart Association recommendations reviewed all of the evidence in 2006, they reaffirmed the association’s position in favor of omega-3s: “…most epidemiologic studies and randomized controlled trials have provided strong evidence of a cardio-protective effect of [omega-3] fatty acids” (Gebauer SK et al. 2006).
The prior, positive clinical trials showed that heart attack survivors who take fish oil capsules suffer fewer cardiac-related deaths and second heart attacks. (Fish oil is not yet proven to reduce the risk of a first heart attack.)
And related research shows additive reductions in major heart-risk factors when people add fish oil to statin drug therapy.
For example, two recent trials in patients with high blood fat and non-HDL cholesterol levels showed that fish oil plus simvastatin (Zocor™) improved blood fat profiles more than simvastatin alone (Davidson MH et al. 2007; Maki KC et al. 2008).
What do omega-3s do, exactly?
World and U.S. researchers agree that omega-3s reduce the risk of strokes, sudden cardiac death, and second heart attacks, by doing several things.
Some of these cardio-related omega-3 effects are better documented than others, and there they are, in rough descending order of the strength of the current consensus:
Well-documented effects with clinical evidence
- Lower blood triglyceride (fat) levels
- Raise levels of “good” (HDL) cholesterol
- Lower levels of all other forms of cholesterol*
- Reduce risk of arrhythmia (erratic heart rhythms)**
- Animal and/or lab evidence only or primarily
- May stabilize arterial plaque by moderating inflammation.
- May reduce oxidation of cholesterol into dangerous forms.
- May reduce accumulation of fat in the main coronary artery (aorta)
**Sudden cardiac death results when heart rhythms go haywire. Omega-3s and certain cardiac drugs stabilize heart rhythms.
These facts explain why the American Heart Association urges everyone to enjoy two servings of fish a week and advises heart patients to take 1000 mg of supplemental fish oil daily.
These were the conclusions of the most recent AHA Scientific Statement on fish and fish oil for heart health: “Omega-3 fatty acids have been shown in epidemiological and clinical trials to reduce the incidence of CVD [cardiovascular disease].” (Kris-Etherton PM et al. 2002)
And the AHA’s 2002 statement was specific about the intake levels needed, saying that people who take 5 grams to 1.8 grams daily (either as fatty fish or supplements) significantly reduce their risk of dying from heart-related reasons or any others.
It appears highly unlike that the unusual results of the new trial will change that advice, for several reasons.
Why the German findings don’t change the overall picture
Three things help explain the new study’s failure to find extra benefits when fish oil is added to optimal conventional therapy:
- Drug therapy for heart attack survivors has advanced since the prior, clearly positive clinical trials were published… a point made by the German researchers themselves.
- The trial’s one-year duration was short, in terms of the time it takes for cardiovascular disease to worsen again following the surgical interventions many of the patients received.
- The German trial excluded anyone who’d already been taking fish oil, to narrow the findings to people who only start taking fish oil after a heart attack. However, omega-3s accumulate in tissues over time, and affect several of the processes that cause heart disease to gradually progress.
“It would be incorrect to say that omega-3 fatty acids are not effective, but we could not find any additional benefits [within one year] after optimizing medical therapy” (AFP 2009).
As in prior clinical trials, each of the patients in the new study received several prescription drugs proven to reduce rates of death and/or heart attacks and strokes.
Researchers must provide proven life-protective drugs to clinical trial participants, even though that ethical requirement makes it harder to identify the benefits provided by an experimental preventive agent such as fish oil.
The German OMEGA trial, in detail
The results of the clinical trial, call OMEGA, were announced by researchers from the University of Heidelberg during the 58th conference of the American College of Cardiology in Orlando, Florida.
The study involved 3,827 patients from 104 German hospitals, heart centers and university hospitals.
Within a few days of suffering a heart attack, patients were placed on one of three regimens:
- Combination drug therapy
- Combination drug therapy + fish oil
- Combination drug therapy + placebo pill
- Aspirin - 95% (ease blood flow and lower inflammation)
- Beta-blockers - 94% (for cardiac arrhythmias and hypertension)
- Statins - 94% (lower cholesterol and inflammation levels)
- Clopidogrel - 88% (ease blood flow)
- Angiotensin-converting enzyme (ACE) inhibitors - 83% (boost heart output, ease blood flow, lower blood pressure)
After one year, there were no significant differences between patients taking prescribed drugs alone, versus patients taking prescribed drugs plus fish oil, in terms of their health status and average blood triglyceride levels.
The health status of the patients in both groups was the same in terms of overall death rates and with regard to rates of “adverse cardiac events”: a term that encompasses heart attacks, stroke, and sudden cardiac death.
As the Germans wrote, “Based on available data, the use of omega-3 fatty acids after an acute coronary syndrome cannot be endorsed [for patients already taking optimal drug therapy].”
However, they were not denying the value of omega-s for overall cardiac health.
Instead, the Germans simply meant that, based on their trial’s outcome, they could not ensure heart attack survivors on state-of-the art drug therapy that they would reduced their cardiac risks further during the first year by also taking omega-3 fish oil.
While this study’s results cannot be dismissed, they’re substantially outweighed by findings from several similar trials, which have demonstrated clear benefits for heart attack survivors.
Given the very large body of credible evidence supporting the hearth benefits of fish and fish oil, we hope that reports on this new trial don’t deter similarly situated heart patients from consuming omega-3s in abundance.
- Agence France Presse (AFP). Omega-3 of no added benefit for heart patients: study. March 30, 2009. Accessed online at http://www.google.com/hostednews/afp/article/ALeqM5j-bZTSdpjXI6V_20CArQjo3ki24g
- Bays H. Rationale for prescription omega-3-acid ethyl ester therapy for hypertriglyceridemia: a primer for clinicians. Drugs Today (Barc). 2008 Mar;44(3):205-46.
- Bays HE, Tighe AP, Sadovsky R, Davidson MH. Prescription omega-3 fatty acids and their lipid effects: physiologic mechanisms of action and clinical implications. Expert Rev Cardiovasc Ther. 2008 Mar;6(3):391-409. Review.
- Davidson MH, Stein EA, Bays HE, Maki KC, Doyle RT, Shalwitz RA, Ballantyne CM, Ginsberg HN; COMBination of prescription Omega-3 with Simvastatin (COMBOS) Investigators. Efficacy and tolerability of adding prescription omega-3 fatty acids 4 g/d to simvastatin 40 mg/d in hypertriglyceridemic patients: an 8-week, randomized, double-blind, placebo-controlled study. Clin Ther. 2007 Jul;29(7):1354-67.
- Gebauer SK, Psota TL, Harris WS, Kris-Etherton PM..n-3 fatty acid dietary recommendations and food sources to achieve essentiality and cardiovascular benefits. Am J Clin Nutr. 2006 Jun;83(6 Suppl):1526S-1535S. Review.
- Kris-Etherton PM, Harris WS, Appel LJ; American Heart Association. Nutrition Committee. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation. 2002 Nov 19;106(21):2747-57.
- Lee JH, O'Keefe JH, Lavie CJ, Marchioli R, Harris WS. Omega-3 fatty acids for cardioprotection. Mayo Clin Proc. 2008 Mar;83(3):324-32. Review. Erratum in: Mayo Clin Proc. 2008 Jun;83(6):730.
- Maki KC, McKenney JM, Reeves MS, Lubin BC, Dicklin MR. Effects of adding prescription omega-3 acid ethyl esters to simvastatin (20 mg/day) on lipids and lipoprotein particles in men and women with mixed dyslipidemia. Am J Cardiol. 2008 Aug 15;102(4):429-33. Epub 2008 May 22. Erratum in: Am J Cardiol. 2008 Nov 15;102(10):1425.
- Marchioli R, Barzi F, Bomba E, et al; GISSI-Prevenzione Investigators. Early protection against sudden death by n-3 polyunsaturated fatty acids after myocardial infarction: time-course analysis of the results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI)-Prevenzione. Circulation. 2002 Apr 23;105(16):1897-903.
- Marchioli R, Marfisi RM, Borrelli G, Chieffo C, Franzosi MG, Levantesi G, Maggioni AP, Nicolosi GL, Scarano M, Silletta MG, Schweiger C, Tavazzi L, Tognoni G. Efficacy of n-3 polyunsaturated fatty acids according to clinical characteristics of patients with recent myocardial infarction: insights from the GISSI-Prevenzione trial. J Cardiovasc Med (Hagerstown). 2007 Sep;8 Suppl 1:S34-7.
- Marchioli R, Schweiger C, Tavazzi L, Valagussa F. Efficacy of n-3 polyunsaturated fatty acids after myocardial infarction: results of GISSI-Prevenzione trial. Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico. Lipids. 2001;36 Suppl:S119-26.
- Qi K, Fan C, Jiang J, Zhu H, Jiao H, Meng Q, Deckelbaum RJ. Omega-3 fatty acid containing diets decrease plasma triglyceride concentrations in mice by reducing endogenous triglyceride synthesis and enhancing the blood clearance of triglyceride-rich particles. Clin Nutr. 2008 Jun;27(3):424-30. Epub 2008 Mar 24.
- Senges J, et al. Presentations 411-6: Randomized Trial of Omega-3 Fatty Acids on Top of Modern Therapy After Acute Myocardial Infarction: The OMEGA-Trial. 58th conference of the American College of Cardiology in Orlando, Florida, Monday, Mar 30, 2009.
- Tonkin AM, Eckermann S, White H, Friedlander D, Glasziou P, Magnus P, Kirby A, Mulray S, Denton M, Sallaberger M, Hunt D, Simes J; LIPID Study Group. Cost-effectiveness of cholesterol-lowering therapy with pravastatin in patients with previous acute coronary syndromes aged 65 to 74 years compared with younger patients: results from the LIPID study. Am Heart J. 2006 Jun;151(6):1305-12.