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pigs flyFrom ‘I smell a rat‘ to ‘when pigs fly’, bad science has been making the rounds of late. The multi-authored article A long-term toxicology study on pigs fed a combined genetically modified (GM) soy and GM maize diet” reports that pigs fed a diet of only genetically modified grain show a markedly higher incidence of stomach inflammation than pigs that ate conventional feed.

This paper is fresh off the press and ready for ravenous consumption by anti-GMO enthusiasts. However, it seems that – post-publication – the paper and its evidence fail the independent peer-review process on many fronts:

The Evidence: David Tribe reviews the paper here: He says, “It’s what some call a fishing expedition in search of a finding, and a known pitfall of animal feeding trials on whole foods…” Tribe points out (among other things) that some of the study’s observations might be attributed to compositional differences in the variety of soybeans or corn fed to the pigs “..there is relatively little information in the paper about nutritional formulation, methods used for producing the pig diets, storage time for the grain and which particular varieties of grain were used in the diets.”

Update – June 14th – - – Anastasia Bodnar expands upon this further in her post in Biofortified Lack of care when choosing grains invalidates pig feeding study: “The authors aimed to do a real world study, with pig feed that can be found in real life. It intuitively seems right to just go get some grain from some farms. After all, that is what pigs eat, right? Unfortunately, it’s just not that simple…To hone in on any differences that may be caused by the GM traits, they would have to use feed with one or more GM traits and feed that doesn’t have the GM traits but that is otherwise as similar as possible. If the feeds aren’t very similar, then we can’t know if any differences in the animals is due to the GM traits or due to something else.”

Update June 14th - – - Dr. Robert Friendship (via Terry Daynard) – swine expert from the University of Guelph – points to methodological problems with “visual scoring” and assessment of ‘inflammation’: “…it was incorrect for the researchers to conclude that one group had more stomach inflammation than the other group because the researchers did not examine stomach inflammation. They did a visual scoring of the colour of the lining of the stomach of pigs at the abattoir and misinterpreted redness to indicate evidence of inflammation. It does not. They would have had to take a tissue sample and prepare histological slides and examine these samples for evidence of inflammatory response such as white blood cell infiltration and other changes to determine if there was inflammation.”

Andrew Kniss clearly demonstrates the failings of the statistical analysis, poking holes in the study’s evidence. He states, “If I were to have analyzed these data, using the statistical techniques that I was taught were appropriate for the type of data, I would have concluded there was no statistical difference in stomach inflammation between the pigs fed the two different diets. To analyze these data the way the authors did makes it seem like they’re trying to find a difference, where none really exist.”

Another matter worth mentioning: in the experiment, half of the pigs died of pneumonia. [update: 50% of the pigs did NOT die but, rather, were 'sick' with pneumonia - my error] This is an indication of bad stewardship. In events such as this, it is only appropriate to throw away the results – maybe a ‘do-over’ (next time using a better methodological approach (and take better care of the pigs)).

Credibility: This was the first time I had ever heard of The Journal of Organic Systems. As Mark Lynas observes (in GMO pigs study: more junk science), “The journal does not appear in PubMed, suggesting it is not taken very seriously in the scientific community.” In the world of science, publishing a good, sound piece of science in a good journal is an indicator of quality and credibility. I mean, think about it… if this study was a ground-breaking piece of ‘all that,’ wouldn’t it have been published by Nature or Science? At the very least, the paper would have been picked up by a journal within the study’s subject area.

Bias: You only need glance at the acknowledgement list at the end of the paper to see that it is a ‘who’s who’ of the anti-GMO world.  This kind of makes the statement “The authors declare that there are no conflicts of interest” pretty much ‘moot.’  One author – Howard Vlieger - is the President of Verity Farms, Iowa, an organization that markets itself as non-GM.  Judy Carman (lead author) is widely known as a long-time anti-biotech campaigner. She even has a website called ‘GMOJudyCarman‘ (launched in late May – timely, no?)

Other interesting bits? In an April 2008 interview, Dr. Carman stated that her work received funding from Jeffrey Smith and the Institute for Responsible Technology. Jon Fagan, listed in the acknowledgements, is the head of Genetic-ID. Genetic-ID is the company that conducted the DNA analysis for the study confirming that the GM corn used contained a combination of NK603, MON863 and MON810 genes (page 40). Genetic-ID is based in Fairfield, Iowa and has satellites the world over. Genetic-ID is a GMO testing company and part of a convoluted network of actors with vested anti-GM interests, weird politics and Vedic-scienc-y stuff, and a long list of celebrities (see here).

It would seem that Carman et al have taken some pages from Seralini’s ‘playbook’ – but there are no ‘silver linings’ here.  This is just another exercise to “prove” that GMOs are dangerous rather than to objectively investigate them. Given the conflict of interests of the authors and affiliates involved, what other conclusion could they come to? The science, however, doesn’t pass the sniff-test. It’s a case of faulty methodology and poorly interpreted data magically making it through the peer review process.  Throw in some colorful (scary) pictures of pig uteri for good measure, add to that a bit of bias and credibility issues and you have the makings for some really ‘shoddy science’.

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  • Check out Fourat Janabi’s post @Fouratj: “Pigs, GMOs and Bullshit Fourat provides a point by point critique of the Carman et al article – Easy-to-consume with none of the BS. :O)
  • Then there is this post from Julee @sleuth4health who quips, “At this point, anybody who’s ever judged a High School Science Fair has got to be thinking “F.”” 
  • Catalyzing Illinois writes Something Smells and its not the Pigs“We are not dealing with “disinterested and objective science” here.”
  • Contrary to Popular Belief: Latest anti-GMO study: more bullshit