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12 June 2013

Mark Lynas Examines Junk GMO Anti-science

While you wait with breath bated for this weekend's Life, the Universe & Everything Else episode on Organic Agriculture, I'd recommend giving this article a read.

Here, Mark Lynas (who has rapidly become my favourite environmentalist) takes aim at a junk science paper out of Australia claiming that a diet consisting of only "genetically modified" grain vastly increases the risk of severe stomach inflammation in pigs. Really, it shows nothing of the kind.

15% of non-GM fed pigs had heart abnormalities, while only 6% of GM-fed pigs did so. Similarly, twice as many non-GM pigs as GM ones had liver problems. Why no headlines here? "Pigs fed non-GMO feed 100% more likely to develop heart and liver problems, study finds" – I can just see it in the Daily Mail. But of course negative results were not what Carman et al were looking for.


Table 3 actually shows that many more pigs fed non-GMO feed had stomach inflammations than those with GMO feed. So 31 non-GM pigs had "mild" inflammation, while only 23 GM pigs had it. For "moderate" inflammation, a GMO diet again seemed to be beneficial: 29 non-GM pigs had moderate inflammation of the stomach, while 18 had it. So that's 40% vs 25%. Do Carman et al perform a test for statistical significance to see if GMO feed has a protective effect on pigs stomachs? Of course not – that's not the result they are after. These findings are ignored.

Instead, it is the next line of data that they play up: for "severe" inflammation 9 non-GM pigs were determined to have it, while 23 GM-fed pigs had it. Shock, horror. You can immediately see how the data is all over the place from the previous results, which also rule out any causal mechanism with GMO feed – if GMO feed is causing the severe inflammation, why is the non-GMO feed causing far more mild to moderate inflammation? It's clearly just chance, and all the pigs are not doing well and suffering stomach problems: about 60% of both sets had stomach erosion.

Previously: Mark Lynas apologises for his past anti-GE activism and calls out the conspiracy-driven thinking that plagues the environmental movement.

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