A pair of studies recently published in the journal Food and Chemical Toxicology (FCT) reveals the double standard used in evaluating the safety of genetically modified (GM) foods, says Claire Robinson, in a July 11 editorial on the website GM Watch.
Editorial double standard
In November 2013, FCT editor A. Wallace Hayes forcibly retracted a study led by researcher Gilles-Eric Seralini. The long-term study had found organ damage, hormone disruption and increased tumor and mortality rates in rats fed NK603 “Roundup Ready” (glyphosate-resistant) GM corn contaminated with glyphosate levels ruled safe by regulators.
In retracting the paper, Hayes called the findings “inconclusive,” because not enough rats were studied and because the variety of rat used (Sprague-Dawley) was particularly prone to tumors.
Researchers worldwide mocked “inconclusiveness” as a rationale for retracting a paper. Jack Heinemann of the University of Canterbury, New Zealand, noted that this criterion would have forced the retraction of the two famous papers in which James Watson and Francis Crick described the structure and replication mechanism of DNA; it was later research that eventually rendered their findings conclusive.
Yet, in April 2014, FCT published a study by DuPont researchers that supposedly proved the safety of GM “Roundup Ready” canola. The study used approximately the same number of Sprague-Dawley rats as the Seralini study and was conducted over a much shorter time period — insufficient to find any long-term health effects.
In addition, the DuPont researchers used a shady practice common to GM industry studies: including a variety of “reference” diets to obscure any findings in a sea of useless data.
“There is… irony in the fact that we are not allowed to suspect that DuPont’s reassuring findings on its own GMO might be a false negative, where a toxic effect exists but is missed because of poor experimental design,” Robinson wrote.
“But conversely we are expected to believe that Seralini’s findings, dramatic as they are, are all false positives and an artefact of the small number of rats used and the rat strain chosen — two factors which miraculously become acceptable in the DuPont study and many other industry studies.”
DuPont data fraud
Perhaps even more troubling is a fact pointed out by Seralini and colleagues in a letter to the editor of FCT: The DuPont study actually fed GM food contaminated with herbicides to both groups of rats in the study. Therefore, the finding of “no health differences” provides no useful information.
Seralini’s team conducted an independent analysis of the Purina brand rat chow used as the standard diet in the DuPont study. The researchers found that the feed was actually composed of 18 percent NK603 GM corn — the same variety tested in the Seralini study, and engineered for the same trait as the Roundup Ready canola that the DuPont researchers were testing.
In addition, the rat chow contained 14.9 percent GM “Bt” corn, which is engineered to produce a pesticide in its tissues. The chow was also contaminated with the herbicide Roundup (glyphosate), as well as the glyphosate metabolite AMPA.
In contrast, the Seralini study used a control feed that was tested free of GM or herbicide contamination.
“The uncontrolled presence of pesticide residues and other GMOs make the study inconclusive,” Seralini and colleagues write. This warrants the study’s retraction, they said.
“To round off this GMO farce,” Robinson writes, “the DuPont authors declare in their paper that ‘there are no conflicts of interest’ — despite the fact that they are employees of the company that stands to profit from the market authorisation of the GMO in question.
And Bryan Delaney, the first author of the DuPont study, is also managing editor of FCT. That interest too goes undisclosed.”
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