An article published in the Journal of the American Medical Association (JAMA), has been widely publicized in the media, for its conclusion that ‘fish oil doesn’t help heart disease”. You can read the full abstract here: Now, let’s take a look at these ‘findings”. First of all this is a type of research called ‘meta-analysis’, in which no actual clinical research at all is done. It simply takes a look at lots of articles published on a particular subject, and tries to draw conclusions. I call this “armchair research”. Particularly when many studies with different research designs are studied together, results can be very misleading. But there are also some assumptions that bear looking at. In case you didn’t click on the link to read the abstract, these were the conclusions of the meta-analysis: “Omega-3 fatty acid supplementation was not associated with a lower risk of all-cause mortality, cardiac death, sudden death, myocardial infarction, or stroke.
I have collected an enormous amount of data that strongly suggest multiple benefits from the consumption of omega-3 fatty acids for cardiovascular disease, cancer, neurological disease, auto-immune diseases, and even in bone, skin and lung health. There is no question that the dietary ratio of omega-3 to omega-6 fats is a major factor in how susceptible people are to chronic inflammation, which underlies most chronic modern maladies. Good quality (molecularly distilled, preserved by potent fat soluble antioxidants) fish oil is, in my opinion, much safer than actually eating fish, as it contains many fewer environmental contaminants, such as mercury, PCBs, dioxins, etc. It also takes a long time for it to be incorporated into cell membranes and other body structures, so it is not something that produces dramatic effects in less than a year, and many of the studies analyzed in this meta-analysis, were shorter than one year–and these were not separated out from the analysis of longer studies.
Another key point is that there was some heterogeneity in study design, including in dosage of omega-3 fatty acid used and patient populations. There is much uncertainty regarding the potency and purity of the over-the-counter supplements. The majority of people taking omega-3 supplements are taking cheap, poor-quality, low-potency, and often even rancid products. The public doesn’t know any different, and unfortunately very few of these studies actually analyzed the products that were used. Moreover, the control groups were exposed to varying amounts of fish oils, and this could account for a lack of effect seen between experimental and control groups. Another issue is that when placebo controls were used, due to the fish odor of omega-3 fatty acid supplements, complete blinding of fish oil studies may not be feasible. This imperfect blinding was not considered in the quality assessment of the studies.
Most of the restenosis studies only presented data among those who completed their follow-up angiogram. Consequently, restenosis data were generally analyzed using a modified intention-to-treat, which may result in biased results (in other words, if someone felt great and didn’t come back for their folowup angiogram, they were counted as a non-responder).
Finally, due to the lack of individual-level data, they did not estimate the change in risk of mortality or cardiovascular outcomes over time. In other words did the folks taking a therapeutic dosage get better results? How much EPA and DHA were people consuming? Of course this is essential information. Availability of individual-level data would also have allowed us to examine which subgroups may derive the greatest benefit from the use of these agents. This study adds nothing to our understanding of the role of omega-3 fatty acids in reducing risk of heart disease, and creates a lot of confusion in the minds of consumers (and doctors), who don’t understand research design. Remember the old adage about computers, which applies equally to meta-analysis studies: “GIGO”. Garbage in, Garbage out. Oh, and you can’t compare completely different types of studies and draw any valid conclusions. Better to go do an actual study. But that requires a lot more money, a lot more thought, and a lot more work. There seems to have been a spate of “supplements don’t work” publications in scientific journals lately, which this one adds to. But the people who experience benefits of high quality supplements in their own bodies over time are not likely to believe them.