GM Free Cymru

GMO risk assessment procedures are woefully inadequate

Séralini GE, de Vendômois JS, Cellier D, Sultan C, Buiatti M, Gallagher L, Antoniou M, Dronamraju KR.

How Subchronic and Chronic Health Effects can be Neglected for GMOs, Pesticides or Chemicals.
Int J Biol Sci 2009; 5:438-443.


Chronic health effects are increasing in the world such as cancers, hormonal, reproductive, nervous, or immune diseases, even in young people. During regulatory toxicological subchronic tests to prevent these on mammalian health, prior commercialization of chemicals, including pesticides and drugs, or GMOs, some statistically significant findings may be revealed. This discussion is about the need to investigate the relevant criteria to consider those as biologically significant. The sex differences and the non linear dose or time related effects should be considered in contrast to the claims of a Monsanto-supported expert panel about a GMO, the MON 863 Bt maize, but also for pesticides or drugs, in particular to reveal hormone-dependent diseases and first signs of toxicities.


We assume that Séralini et al. [5] methodology can discriminate potential false positive and GM-linked effects, avoiding to some extent false negative ones, in the best way we can do for this discussed and too limited protocol already in use for commercialized GMOs. These GM-linked effects are then considered as signs of toxicity in the 90 days, not proofs of toxicity. The biological plausibility of a subchronic or chronic side effect of the GM diet, linked to the new toxin in the mammalian regimen, or due to the mutagenesis effect of the genetic modification itself, is thus non negligible. Finally it should be stressed that statistically significant effects of GM diets, or of residues of pesticides that are contained by GMOs, have also been observed in other instances [21-25], but not in all studies [26, 27] enlightening the necessity of a case-by-case approach, and that the real toxicological studies are quite limited up to date for that [28]. All these observations taken together in our opinions do not allow a clear statement of toxic effects, but to suggest them as such, because they are clearly undeniable. Now, to any good researcher similar results would mean that there is much to be improved in the planning of experimental design; and thus to increase their resolution power to obtain unequivocal statements, for instance increasing the duration and/or the number of rats tested. Generally speaking it seems to us unbelievable that a risk assessment carried out only on forty rats of each sex receiving GM rich diets for 90 days (yielding results often at the limits of significance) have not been repeated and prolonged independently. We should overall take into account the fact that the analysed GM product could be fed long-term to people and animals of various ages and sexes, and with various pathologies.

We call for more serious standardized tests such as those used for pesticides or drugs, on at least three mammalian species tested for at least three months employing larger sample sizes, and up to one and two years before commercialization, for GM food or feed specifically modified to contain pesticide residues. We also call for a serious scientific debate about the criteria for testing significant adverse health effects for pesticides or chemicals, but overall for GM food or feed products, such as MON 863


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Author contact Correspondence to: Prof. Gilles-Eric Séralini, PhD, Institute of Biology and CRIIGEN, University of Caen, Esplanade de la Paix, 14032 Caen Cedex, France.

Tel +33 2 31 56 56 84; Fax +33 2 56 53 20;