Mainstream medicine has failed us yet again. The recent paper published in the Journal of the American Medical Association that attempts to discount the ability of omega-3s to lower heart disease risk is already generating headlines such as, "Omega-3 Supplements Don't Lower Heart Disease Risk After All" and "For Heart Health, Fish Oil Pills Not the Answer."
With literally thousands of studies in support of the health benefits of omega-3s -- heart-health benefits leading the pack -- to discount omega-3s based on this paper or the previous two similar papers published in previous months, would be ridiculous at best, and "could be harmful to public health" at worst, in the words of Adam Ismail, executive director of the Global Organization for EPA and DHA Omega-3 (GOED).
The systematic review and meta-analysis selected 20 studies (out of 3,635) of over 68,000 people taking either omega-3 supplements or consuming omega-3s in the diet. Participants consumed an average of 1.37 grams of EPA + DHA (or a median intake of 0.89 grams EPA + DHA -- remember that median dose indicates that the highest number of individuals took this dosage, whereas the mean dosage can be skewed by a few participants taking much higher doses). They found that omega-3 supplementation was not associated with a lower risk of death, heart attack, or stroke.
This paper was preceded by another paper published in the New England Journal of Medicine in July, which found that daily omega-3 supplementation did not reduce the rate of cardiovascular events in patients with diabetes (who are at high risk) (2). This paper was preceded by yet another paper published in the journal Archives of Internal Medicine in May, which found omega-3 supplementation did not prevent against overall cardiovascular events in patients who already had cardiovascular disease (3).
These studies would be enough to make anyone taking omega-3 fish oils question why. Unless you take a deeper look.
The main argument against all of these studies is that the patients enrolled in the trials are already taking an array of cardiovascular drugs. This makes it very difficult to detect benefits of omega-3s because the drugs themselves are already lowering risk of cardiovascular events. The earlier trials reporting positive benefits of omega-3s on heart health did not have this problem, as people were not taking the types of medications that they are today.
In support of this argument is a study published in the European Heart Journal in February 2012, which included over 4,000 men and women who had previously experienced a heart attack. Some were taking statins, and some were not, but all received omega-3 supplementation (4). The participants taking omega-3s plus statins were found to not have a reduction in cardiovascular events after three and a half years, but those who were taking omega-3 supplements without also taking statins did experience a decreased risk of cardiovascular events.
An important aspect that many commenters on these studies have failed to mention is that measurements of omega-3 levels were not taken. Specifically, a measurement of red blood cell (RBC) membrane levels of the omega-3 fatty acids EPA and DHA is the best indication of long-term intake -- and thus, incorporation into the tissues of the body where they are needed -- of omega-3s. This test is known as the Omega-3 Index. People with an Omega-3 Index below four per cent are at high risk of developing coronary heart disease and people with an Omega-3 Index over eight per cent are at low risk (5).
To not measure the Omega-3 Index in people taking low doses of omega-3s, as was the case in all of these recent studies, is a mistake. Sure, patients received omega-3 supplements or were told to eat a certain amount of fish -- on average, 1-1.5 grams daily -- but let's face it, many people probably skip their supplements or opt for steak over salmon when they should be consistent. Not to mention, the Omega-3 Index most common in the United States is below four per cent, so most people in these studies likely started out with very low levels. And, people metabolize and absorb omega-3s differently.
To measure EPA and DHA levels in the RBC membranes ensures that participants do indeed have heart-protective levels of omega-3s in their bodies. These studies cannot give us that assurance. It reminds me of the ridiculous vitamin D studies that found no benefit of low-dose vitamin D. The headlines read similar to the headlines about these omega-3 studies. Yet the studies utilized dosages far too small to adequately raise vitamin D levels and therefore would not show clinical benefit. Studies like these only serve to confuse the mass public, and make the researchers look less than intelligent.
When studies are performed using higher EPA + DHA dosages and measurement of the Omega-3 Index with longer follow-up periods (more than two years!) and in people not taking cardiovascular drugs, I'll be ready to report it. For now, keep taking your omega-3s to support heart health.
1) E. Rizos, et al., "Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events." JAMA. 2012;308(10):1024-1033.
2) S.M. Kwak, et al., "Efficacy of omega-3 fatty acid supplements (eicosapentaenoic acid and docosahexaenoic acid) in the secondary prevention of cardiovascular disease: a meta-analysis of randomized, double-blind, placebo-controlled trials." Arch Intern Med. 2012 May 14;172(9):686-94.
3) J. Bosch, et al., "n-3 fatty acids and cardiovascular outcomes in patients with dysglycemia." N Engl J Med. 2012 Jul 26;367(4):309-18.
4) S.R. Eussen, et al., "Effects of n-3 fatty acids on major cardiovascular events in statin users and non-users with a history of myocardial infarction." Eur Heart J. 2012 Jul;33(13):1582-8.
5) W.S. Harris, "The omega-3 index as a risk factor for coronary heart disease." Am J Clin Nutr. 2008 Jun;87(6):1997S-2002S.