Controversial gene corn study withdrawn

Editor finds data as not meaningful, author insists on correctness

Genetically modified maize: harmless or harmful? © USDA
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Do GM maize and pesticides cause breast cancer and kidney failure? Already a year ago, the French scientist Gilles-Éric Séralini tried to answer this. The publication, which has since become known only as the "Séralini Study", has been causing waves in the scientific community since September 2012. Insignificant, unscientific, flawed or even fake, these were the allegations. Other scientists found the study worrying. More than a year later, the magazine's publishers want to withdraw the controversial study. The discussions around the topic will however hardly end this.

Investigation of pros and cons is appropriate

Genetically manipulated organisms in agriculture are the subject of much discussion. Proponents promote higher crop yields, thus better supply and a big step in the fight against the world hunger problem, and of course rising sales. Opponents point to unpredictable effects on the ecosystem, as well as unknown health risks due to altered plants and active ingredients. Scientific investigations of pros and cons of genetically modified organisms are therefore quite appropriate.

What was the reason for the ongoing discussions? The study by Gilles-Éric Séralini should help to answer some unanswered questions, using products from the American company Monsanto. Monsanto has been marketing a herbicide called RoundUp since the 1970s, followed by genetically modified and thus RoundUp-resistant seeds. Farmers can thus eliminate weeds with RoundUp, while the crop and thus their own harvest remains intact.

Long-term effects of GM corn on rats

Séralini is known as a dedicated opponent of GM food. His research group at the University of Caen had studied the long-term effects of RoundUp and a genetically modified corn variety from Monsanto. They fed rats with RoundUp-resistant corn throughout their life cycle. For some animals, they also added feed and drinking water mixed with the herbicide. The results were published in the magazine "Food and Chemical Toxicity" (FCT).

The result of the Séralini study: RoundUp and RoundUp-resistant corn lead to liver and kidney failure, and in females more often to breast tumors. Already the kind of publication attracted attention. Séralini organized a press conference and announced a documentary on the results. Journalists who read a preview copy of the study had to commit to silence from other scientists. display

Criticism of the study was not long in coming. The editorial board of FCT was overruled with complaints: S ralini's experiments were poorly planned and carried out, the rat strain used was unsuitable for this type of experiment, his control groups were insufficient to disallow his statistical evaluation Possible, the validity of the results doubtful. The Association of Biology, Life Sciences and Biomedicine (VBIO eV) was critical. Key issues were the selection of rats and statistical defects.

Sprague-Dawley rat Jean-Etienne Minh-Duy Poirrier / CC-by-sa 2.0

Questionable rat selection and statistics?

The rats were so-called Sprague-Dawley rats. This strain is routinely used in animal studies, but is considered unsuitable for long-term experiments. Since it is an inbred strain, the animals have a very high tumor risk from the outset. Tumor diseases, as S ralini has observed, are not uncommon in these animals, an increased tumor occurrence is therefore difficult to detect. S ralini opposes the fact that the Monsanto toxicity studies on RoundUp also used Sprague-Dawley rats and therefore only comparable results could be obtained. However, the studies at Monsanto only lasted for more than 90 days, not more than two years.

Also questioned was the statistical relevance of the results. Up to 80 percent of the animals in the test groups compared to 30 percent in the control group had tumors developed. That sounds like a clear difference at first. However, with a size of only ten rats per group, this means eight affected rats in the test group and three animals in the control. From the mean value five, which would be expected for a random distribution, both values ​​are not far away and can still be explained by statistical deviations. S Kritikralini counters criticizing the size of the group with reference to the guidelines of the Organization for Economic Co-operation and Development (OECD), which recommend a minimum of ten animals as a group size.

Criticisms and Counter-Notifications

S ralini published a detailed answer to all the criticisms in FCT, but the discussions did not diminish. All of these criticisms and objections eventually led the publisher of the magazine to ask the author team of the study for access to the raw data. This possibility is well defined in the guidelines of most magazines. In practice, however, such an independent review is extremely rare. In most of these cases, there is a serious suspicion of data falsification.

In a letter dated 19 November 2013, A. Wallace Hayes, Editor-in-Chief of FCT, informed Séralini of the results of this review. He recommends that he withdraw the study, otherwise the withdrawal would be made by the magazine. In the attached statement, he praises Séralini's comprehensive cooperation and expressly points out that no falsification or deliberate misinterpretation of the data was found. However, based on the data, no clear findings are possible and the published results are therefore unsustainable.

Inadmissible, unscientific, unethical

Séralini and his group insist on the correctness of their study and the significance of the results. They expressly refused to take the study back on their own. In response, the trade magazine moved on 28 November 2013, the article. Instead of the article is now the reference to the withdrawal and the detailed statement and justification of the magazine. At the moment, however, the study, which is published as an open-access document, is still available for free - and is even number 1 in the magazine's most-clicked studies.

Séralini has threatened legal action in the event of withdrawal. The Enlightenment GMWatch refers to the withdrawal on its website as "inadmissible, unscientific and unethical", and sees all allegations against mega-corporations like Monsanto confirmed. An end to the discussion about the Séralini study is therefore not yet in sight. The further attention of scientists of all points of view, Séralini is certain.

Original study, FCT 2012; doi: 10.1016 / j.fct.2012.08.005

Statement of the publisher

Reaction of Sérafinis Institute CRIIGEN

(Food and Chemical Toxicity, CRIIGEN, VBIO, 02.12.2013 - AKR)