EFSA stands by its opinion: No concerns
(28 June 2007) The European Food Safety Authority (EFSA) has published an opinion in which it once again assesses genetically modified MON863 Bt maize as safe for humans, animals and the environment. MON863 had met with repeated criticism, which always centred on a feeding study with rats submitted by the authorisation applicant Monsanto with its application documentation. In March, a working group led by French scientist Gilles Eric Séralini published another evaluation of the data and expressed doubts about the safety of MON863.
The European Commission then called on EFSA to re-examine its previous opinion in the light of Séralini’s re-evaluation of the data. For this purpose EFSA was to obtain opinions from the EU member states as well.
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Background: On 2 April 2004, EFSA’s GMO Panel published a first opinion on MON863, in which the experts concluded that the maize could be classed as safe for humans, animals and the environment. The safety assessment was based in part on the above-mentioned 90-day feeding study with rats conducted by Monsanto. In the study, male and female rats received either a diet of MON863 maize in various dosages or the conventional parent line or other conventional maize varieties. Statistically significant deviations were found in the animals fed on MON863 in isolated cases, both in relation to the animals’ growth and to various biological parameters. These were evaluated by EFSA as “not biologically relevant”. However, the public, and French scientists in particular, had doubts about the safety of MON863. The central question was whether the observed deviations in the rats fed on MON863 fall within normal ‘biological variation’ or whether they should be regarded as indicators of health risks. Further expert opinions were obtained. In October 2004 the EFSA expert panel once again consulted on the issue and confirmed the opinion it had published in the spring: the feeding experiments did not give any indication that MON863 could be harmful to humans or animals. But this did not put an end to the discussion surrounding MON863. Once Greenpeace had gone to court to force publication of the full feeding study in June 2005, Séralini’s working group started re-evaluating the original data from the Monsanto study. In their analysis, Séralini and his team come to the conclusion that rats fed on MON863 maize grains showed slight, but dose-dependent deviations in growth in both sexes. In addition, some of the statistically significant deviations, e.g. for the blood and urine measurements, could be interpreted as indications of liver or kidney toxicity. |
Third EFSA opinion: no new findings
An EFSA working group looked at the statistical methods used in the Séralini analysis, met the authors of the study and carried out a reevaluation themselves. In addition, a French institute was commissioned to carry out another analysis of the statistical evaluation of the data. The authorities responsible in the member states were also asked to give an opinion.
In summary, EFSA comes to the following assessment:
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All statistically significant deviations for individual test parameters in the feeding study were analysed and assessed again, this time taking into account the type and significance, extent and frequency, both with regard to possible dose dependency and gender effects.
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In most cases, there is no correlation between the observed differences and a specific dose or the gender of the trial animals. Sometimes there were lower values, sometimes higher, which can be interpreted as isolated, random phenomena. Differences in blood and urine values could not be confirmed in the tissue sections and therefore do not indicate organ damage.
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Séralini’s hypothesis, that the observed changes in weight gain could indicate a disturbance of the hormone balance, cannot be proved by the experimental data.
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Unlike Séralini, the GMO Panel assessed the biological relevance of all statistically significant differences between the animals fed on GM maize and the isogenic control group. This also included looking at natural variability, which it was possible to estimate using the data from the control groups fed on other conventional maize varieties. Against this background the effects were classed as not biologically relevant.
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In the view of the GMO Panel, the Séralini study provides no new indications of toxicologically relevant findings. The panel therefore sees no reason to alter the opinion published in 2004 which states that MON863 has no negative effects on the health of humans, animals or the environment.
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A range of different statistical methods were used for the assessment. The GMO Panel believes there is a need to standardise the statistical methods for the assessment of animal studies and has already formed a working group for this task.
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