Last month’s study out of France that said genetically modified corn and a related herbicide caused organ damage, tumors, and early death among rats broke too many rules and should be dismissed as “of insufficient scientific quality,” the European Food Safety Authority (EFSA) says.
When it was published in Food and Chemical Toxicology in September, the study led by Professor Gilles-Eric Séralini seemed like it might be a game-changer because it questioned the safety of Roundup Ready corn, or NK 603, manufactured for use in both the U.S. and Europe by biotech giant Monsanto.
And now in a major push-back against the study out of the University of Caen, EFSA says there are just too many shortcomings to consider the work to be scientifically sound.
“Some may be surprised that EFSA’s statement focuses on the methodology of this study rather than its outcomes; however, this goes to the very heart of the matter,” said Per Bergman, the agency’s director of scientific evaluation of regulated products. “When conducting a study it is crucial to ensure a proper framework is in place. Having clear objectives and the correct design and methodology create a solid base from which accurate data and valid conclusions can follow. Without these elements a study is unlikely to be reliable and valid.”
Bergman headed an EFSA task force from the agency’s genetically modified organisms (GMO), pesticide, and scientific assessment units. It concluded the study has many issues that need to be resolved. Specifically called out were:
• The strain of rat used in the two-year study is prone to developing tumors during their life expectancy of approximately two years. This means the observed frequency of tumors is influenced by the natural incidence of tumors typical of this strain, regardless of any treatment. This is neither taken into account nor discussed by the authors.
• The authors split the rats into 10 treatment sets but established only one control group. This meant there was no appropriate control for four sets — some 40 percent of the animals — all of whom were fed GM maize treated or not treated with a herbicide containing glyphosate.
• The paper has not complied with internationally recognized standard methods — known as protocols — for setting up and carrying out experiments. Many of these procedures were developed by the OECD (Organization for Economic Cooperation and Development).
• For a study of this type, the relevant OECD guideline specifies the need for a minimum of 50 rats per treatment group. Séralini et al used only 10 rodents per treatment set. The low number of animals used is insufficient to distinguish between the incidence of tumors due to chance rather than specific treatment effects.
• The authors have not stated any objectives, which are the questions a study is designed to answer. Research objectives define crucial factors such as the study design, correct sample size, and the statistical methods used to analyze data — all of which have a direct impact on the reliability of findings.
• No information is given about the composition of the food given to the rats, how it was stored or details of harmful substances — such as mycotoxins — that it might have contained.
• It is not possible to properly evaluate the exposure of the rats to the herbicide, as intake is not clearly reported. The authors report only the application rate of the herbicide used to spray the plants and the concentration added to the rats’ drinking water but report no details about the volume of the feed or water consumed.
• The paper does not employ a commonly used statistical analysis method nor does it state if the method was specified prior to starting the study. The validity of the method used is queried and there are questions over the reporting of tumor incidence. Important data, such as a summary of dropouts and an estimation of unbiased treatment effects have not been included in the paper.
• Many endpoints — what is measured in the study — have not been reported in the paper. This includes relevant information on lesions, other than tumors, that were observed. EFSA has called on the authors to report all endpoints in the name of openness and transparency.
Bergman said the consideration of possible long-term effects of GMOs has been, and will continue to be, a key focus of EFSA’s work to protect animals, humans and the environment.
In the controversial study, rats fed Roundup Ready corn were exposed to Roundup weed killer, and reportedly developed tumors, liver and kidney damage and early death.
The findings instantly became political fodder in both the U.S. and Europe. They’ve figured into California’s “Right to Know” campaign (Proposition 37), calling for labeling food products that are genetically modified. And, Europe’s biotech industry known as EuropaBio said the research was being used as a “scare tactic.”
One GMO opponent sees a silver lining in EFSA’s rebuke of the study — it may led to accepted methodologies for testing the safety of future GMO crops.© Food Safety News