OPEN ACCESS VOLUME 33, NUMBER 4 PUBLISHED: AUGUST 2018 REVIEW ARTICLE COMMENTARY
Omega-3 Fatty Acids and Cardiovascular Disease
Author(s): Damien Downing1; Robert G Smith2 1. President of the British Society for Ecological Medicine, London, UK; 2. Research Associate Professor at the University of Pennsylvania Perelman School Of Medicine
Introduction The Cochrane Database of Systematic Reviews has just updated its own review: Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease (Abdelhamid, Brown, Brainard, et al., 2018). Here’s our take on it: Michael Pollan, the brilliant food writer, reckoned you could sum up what to do about nutrition and diets in 7 words; “Eat food, not too much, mostly plants.” That sums up both what’s best for humans and what’s best for the planet. We reckon you can sum up what’s wrong with evidence-based medicine (EBM) in 10 words; “Evidence is a waste of data; systematic reviews are palimpsests.” You can use that as a knife to quickly dissect this study. There are many things wrong with this review. Somebody’s PR department has spun the review’s “no clear evidence of benefit” into “evidence of no benefit” - absence of evidence becoming evidence of absence. And clearly the media were entirely happy to take that one and run with it. Systematic Reviews are Palimpsests What’s a palimpsest? Back when things got written on vellum, an animal skin, not on paper, you didn’t throw it away; you recycled it and wrote over the original. It was called a palimpsest. A systematic review gives an opportunity to write over the conclusions of a whole list of papers with your new version of the truth. You do that by the way that
you select and exclude them. For instance there was a meta-analysis (that’s a systematic review with more numbers) in 2005 that concluded that vitamin E supplements significantly increased the risk of death (Miller, Pastor-Barriuso, Dalal, et al., 2005). The way they did that was to rule out any study with less than 10 deaths - when fewer deaths was exactly the outcome they were supposed to be looking for. The reason they gave for doing that was “because we anticipated that many small trials did not collect mortality data.” We’re not buying it; they used it as a trick to enable them to get the negative result they wanted - to over-write the findings of a long list of original studies. And here we have authors doing the very same thing in this omega-3 study - and upping the ante slightly. Now the threshold is 50 deaths. Fewer than that and your study is ruled out of the final, supposedly least biased, analysis…on the grounds that it’s more biased. We don’t know how they could keep a straight face while saying (our interpretation); “The studies with fewer deaths showed more benefit from omega-3s, so we excluded them.” At least that’s what happened back in 2004 when the first version of this came out (Hooper, Thompson, Harrison, et al.,2004). But this is the 8th update (we think) and they no longer bother to tell you about what they included or excluded in detail, so we can only assume that if they had changed that exclusion they would have told us. The weird thing is that they are allowed to do it. Nutrition researcher Dr. Steve Hickey has shown that in systemat-
© 2018 International Society for Orthomolecular Medicine ISSN 0317-0209
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