GMOs are on the front of the stage from Tuesday, March 13 publication of a study concluding that the toxicity of a genetically modified corn. Should we worry about these results? Some answers toxicologist with Jean-Francois Narbonne.
Aline PÉRIAULT
It is a corn genetically modified to resist attack by an insect pest, the codling moth. Codenamed MON 863. This GMOs developed by Monsanto revives the debate on the toxicity of transgenic plants. Reason: a study published in the journal Archives of Environmental Contamination and Toxicology suggests that the corn could be toxic to the liver and kidneys.
Small back. In 2004, for approval of its corn, Monsanto ordered a toxicology study on 400 rats to be fed for 90 days with the famous maize MON 863. The results of this study are published in August 2005 by Food and Toxical Toxicology. These results conclude already variations of biological parameters between animals fed MON 863 and those who eat its isomer, the variety of non-genetically modified. The experts concluded that while these differences are a natural variability and corn MON 863 is approved for marketing.
Risk to health?
But Greenpeace does not mean it that way and the association appealed to the courts to be able to read the data from this study. This authorization will be given their spring 2005 by the Appeal Court's German Muenster. Greenpeace says while the Research Committee and independent information on genetic engineering, the task of resuming any analysis of these data to determine whether or not the genetically modified corn could be hazardous to health. The researcher Gilles Eric Séralini responsible for the study, then reaches the conclusion that the consumption of MON 863 has consequences on the health of rats: changes in kidney weights and liver, reticulocyte count and triglycerides and modified chemical reductions with urinary sodium and phosphorus up to 35%.
Prof. Jen-Francois NarbonnePeut we deduce that the corn is dangerous to your health? "Not so simple answer toxicologist Jean-Francois Narbonne. Beyond the debate about the toxicity of GMOs, the controversy around this corn reveals a real substantive issue on the evaluation of these transgenic plants. How do you declare a GMO is toxic to your health? First, we test separately the safety of the molecule of interest recently produced by the plant. For example, here the molecule which confers resistance to corn borers is extracted and evaluated through a classical toxicological tests - are administered different doses of the substance to animals and watch its effects. But with regard to genetically modified plants, researchers are also asked to test the plant in its entirety. Indeed, how can we be sure that the manipulation that can produce the substance to resist certain insect did not also allowed the plant to synthesize a new molecule, which itself could be toxic?
To find out, foods like corn that are evaluated following the same protocols as any chemical. And therein lies the rub for the toxicologist. "These tests are not applicable to food! Is it because they can not be administered to animals at doses beyond what he can eat ... In addition these tests induce nutritional imbalances that could distort the analysis. "Yes, but when comparing two groups of rats fed with either transgenic maize or with its isomer, we can still draw conclusions? "Not so obvious, warns Professor Narbonne. Indeed there may be variability between the group fed with the GMO, the group fed corn origin and the group fed a normal diet that can go up to 20% without necessarily be significant. In the case of MON 863, the researchers showed 35% of such differences on the excretion of sodium and phosphorus, is it significant? "It may be, meets the toxicologist ... like it can not be. "
Toxicological testing obsolete!
For Jean-Francois Narbonne it is impossible to determine the toxicity of the famous MON 863 without having analyzed all the results. "Not only testing protocols are completely obsolete, but also the choice of statistical tool used to analyze the results may lead to completely different interpretations. If we add the fact that animal models such as rats do not necessarily lend themselves to extrapolation to humans, we understand better that this issue of Toxicological tests opens the door to controversial situations like that occur Today with the MON 863 maize, "says the researcher. The principle of the test itself is subject to discussion, how then does not lose focus on the results of this famous experiment?
So how do we know with certainty if a GM food is toxic to your health? For Jean-Francois Narbonne is obvious: "we must abandon the toxicological testing of the 50s who are completely obsolete, and then use other reliable methods to allow toxicologists to answer these questions. A word to the wise ...
Aline PÉRIAULT
It is a corn genetically modified to resist attack by an insect pest, the codling moth. Codenamed MON 863. This GMOs developed by Monsanto revives the debate on the toxicity of transgenic plants. Reason: a study published in the journal Archives of Environmental Contamination and Toxicology suggests that the corn could be toxic to the liver and kidneys.
Small back. In 2004, for approval of its corn, Monsanto ordered a toxicology study on 400 rats to be fed for 90 days with the famous maize MON 863. The results of this study are published in August 2005 by Food and Toxical Toxicology. These results conclude already variations of biological parameters between animals fed MON 863 and those who eat its isomer, the variety of non-genetically modified. The experts concluded that while these differences are a natural variability and corn MON 863 is approved for marketing.
Risk to health?
But Greenpeace does not mean it that way and the association appealed to the courts to be able to read the data from this study. This authorization will be given their spring 2005 by the Appeal Court's German Muenster. Greenpeace says while the Research Committee and independent information on genetic engineering, the task of resuming any analysis of these data to determine whether or not the genetically modified corn could be hazardous to health. The researcher Gilles Eric Séralini responsible for the study, then reaches the conclusion that the consumption of MON 863 has consequences on the health of rats: changes in kidney weights and liver, reticulocyte count and triglycerides and modified chemical reductions with urinary sodium and phosphorus up to 35%.
Prof. Jen-Francois NarbonnePeut we deduce that the corn is dangerous to your health? "Not so simple answer toxicologist Jean-Francois Narbonne. Beyond the debate about the toxicity of GMOs, the controversy around this corn reveals a real substantive issue on the evaluation of these transgenic plants. How do you declare a GMO is toxic to your health? First, we test separately the safety of the molecule of interest recently produced by the plant. For example, here the molecule which confers resistance to corn borers is extracted and evaluated through a classical toxicological tests - are administered different doses of the substance to animals and watch its effects. But with regard to genetically modified plants, researchers are also asked to test the plant in its entirety. Indeed, how can we be sure that the manipulation that can produce the substance to resist certain insect did not also allowed the plant to synthesize a new molecule, which itself could be toxic?
To find out, foods like corn that are evaluated following the same protocols as any chemical. And therein lies the rub for the toxicologist. "These tests are not applicable to food! Is it because they can not be administered to animals at doses beyond what he can eat ... In addition these tests induce nutritional imbalances that could distort the analysis. "Yes, but when comparing two groups of rats fed with either transgenic maize or with its isomer, we can still draw conclusions? "Not so obvious, warns Professor Narbonne. Indeed there may be variability between the group fed with the GMO, the group fed corn origin and the group fed a normal diet that can go up to 20% without necessarily be significant. In the case of MON 863, the researchers showed 35% of such differences on the excretion of sodium and phosphorus, is it significant? "It may be, meets the toxicologist ... like it can not be. "
Toxicological testing obsolete!
For Jean-Francois Narbonne it is impossible to determine the toxicity of the famous MON 863 without having analyzed all the results. "Not only testing protocols are completely obsolete, but also the choice of statistical tool used to analyze the results may lead to completely different interpretations. If we add the fact that animal models such as rats do not necessarily lend themselves to extrapolation to humans, we understand better that this issue of Toxicological tests opens the door to controversial situations like that occur Today with the MON 863 maize, "says the researcher. The principle of the test itself is subject to discussion, how then does not lose focus on the results of this famous experiment?
So how do we know with certainty if a GM food is toxic to your health? For Jean-Francois Narbonne is obvious: "we must abandon the toxicological testing of the 50s who are completely obsolete, and then use other reliable methods to allow toxicologists to answer these questions. A word to the wise ...
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