Swift response to paper on feeding GMO corn, glyphosate

January 2013

Swift response to paper on feeding GMO corn, glyphosate

On September 19, 2012, the Elsevier journal Food and Chemical Toxicology released online a paper entitled “Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize” by Gilles-Eric Séralini and co-workers (50:3221–3231, 2012; doi: http://dx.doi.org/10.1016/j.fct.2012.08.005). The uproar following the publication of this study has not yet abated.

The study looked for adverse health effects in rats that were fed Monsanto’s NK603 corn, which was developed to resist the herbicide glyphosate. (The European Commission approved NK603 for use in feed and other products in 2004 and in food in 2005.) The researchers announced that the rats (i) had a higher incidence of cancers, (ii) had larger cancerous tumors, and (iii) died earlier than controls. The authors summarized their results, saying, “These results can be explained by the nonlinear endocrine-disrupting effects of Roundup [glyphosate], but also by the expression of the transgene in the GMO and its metabolic consequences.”

The dire health effects reported by Séralini and co-workers do not correspond with those from about a dozen other long-term studies of different GM crops (Snell, C., et al., Food Chem. Toxicol. 50:1134–1148, 2012).

The experiments of Séralini and co-workers involved feeding Sprague-Dawley rats for two years (i) with isogenic non-transgenic (control) corn, (ii) with NK603 corn—at three different levels–that either had or had not been treated during the growing season with glyphosate, and (iii) with isogenic non-transgenic corn and with glyphosate in their drinking water. According to the authors, this is the first study to look at long-term effects of NK603 consumption in rats, whose lifespans are about two years. Earlier, Monsanto had sponsored a 90-day feeding trial of NK603 in rats, the current regulatory norm.

Responses to the release of this paper were swift. For example, Russia halted all imports of US corn, which has GM constituents. The European Food Safety Agency (EFSA; Parma, Italy) reviewed the paper and concluded it was “of insufficient scientific quality to be considered as valid for risk assessment.” Furthermore, the EFSA review found “that the design, reporting and analysis of the study . . . are inadequate.”

In its review, EFSA identified issues with the strain of rat used (Sprague-Dawley rats are prone to developing tumors during their life expectancy, no matter what they are fed, particularly if their food intake is not restricted), inadequate controls, noncompliance with standard protocols (such as those developed by the Organisation for Economic Cooperation and Development), insufficient number of experimental animals, inadequate statement of objectives of the experiments, absence of data on the composition of the food given to the rats or on the analysis for the presence of harmful substances in the food, absence of data on volume of food and water consumed, and questionable statistical analysis.

EFSA reported sending two letters to Séralini, one dated October 4 and another on October 18, requesting further data to use in its evaluation on any safety issues involved with NK303. On October 22, EFSA said it had not yet received a response.

Séralini responded in the press by saying he and his co-workers would not release their data until EFSA released the data it had used to authorize the approval of NK603 in Europe. According to FoodNavigator.com on October 22, EFSA complied with this request.

Many other scientists questioned the study’s methodology and findings. More than 700 scientists and academics signed a petition urging Séralini and co-workers to release the study data. If the data were not forthcoming, the petitioners urged that the paper be retracted from Food and Chemical Toxicology.

Elsevier responded on November 7 by publishing 16 letters critiquing the study online alongside the original paper by Séralini and co-workers. On November 9, Elsevier published the authors’ responses to these critiques. There, the authors tabulated their rebuttals to their critics and promised further publications on the subject.

In an EFSA statement issued on November 28, Per Bergman, director of scientific evaluation for regulated products directorate at EFSA, said: “EFSA’s analysis has shown that deficiencies in the Séralini et al. paper mean it is of insufficient scientific quality for risk assessment. In addition, several national organisations were independently mandated by Member States to assess this study. These reviews have demonstrated a consensus among a significant part of the EU risk assessment community that the conclusions of Séralini et al. are not supported by the data in the published paper. We believe the completion of this evaluation process has brought clarity to the issue.”

Another aspect of this report that struck a sour note was the orchestrated manner in which Séralini released it at a press conference on September 19. The paper had been embargoed until that conference, and the journal Nature reported that science writers given pre-embargo access were required to sign a confidentiality agreement that prevented them from seeking outside comments from scientific experts in advance of the study’s release, an unusual requirement (Nature 490:158, 2012). On September 26, Séralini’s book Tous Cobayes? [translation: All of Us Guinea-Pigs Now?] was released. It describes his efforts to show in the laboratory the long-term toxic effects of genetically modified (GM) food and pesticides. There is also an accompanying film by the same name and a television documentary.

Séralini is a molecular biologist with the University of Caen, France, and heads the scientific board of the Paris-based Committee for Research Independent Information on Genetic Engineering (CRIIGEN). Séralini carried out the research in collaboration with CRIIGEN, which says in Article 3 of its Articles of Association that its objective is “To carry out research and provide information on genetic engineering and its impact in the fields of biology, the environment, agriculture, food, medicine and public health.”

Lively accounts of the issues involved as they developed appear at GMOs Are A Pesticide Sponge And Other Weird Tales Of Gilles-Eric Seralini and at Monsanto's GM Corn And Cancer In Rats: Real Scientists Deeply Unimpressed. Politics Not Science Perhaps?.

Excerpted from Biotechnology News, Inform, January 2013.