In September of 2012, the peer review journal Food and Chemical Toxicology published the most rigorous study of its kind (Séralini et al) evaluating the long-term effects of consuming Genetically Modified (GM) corn and Monsanto’s NK603 glyphosate-based herbicide Roundup on rats.

The results of this study were devastating for the biotech industry on several fronts.

“Significant biochemical disturbances and physiological failures”

The original study found severe liver and kidney damage and hormonal disturbances in rats fed both GM maize and low levels of Roundup below allowable limits in drinking water:

  • In female rats, all treated groups died 2 to 3 times more than controls and more rapidly than occurred in 3 male groups fed GMOs. Females developed large mammary tumors almost always more often and earlier than controls. The pituitary was the second most affected organ because the sex hormonal balance was modified by GMO and Roundup treatments.
  • In treated males, liver congestions and necrosis were 2.5 to 5.5 times higher than controls. Significant and severe kidney nephropathies were also generally 1.3 to 2.3 times greater. Males presented 4 times more large palpable tumors that occurred 600 days earlier than the control group.
  • Underscoring the inadequacy of 90-day trials, the first large detectable tumors occurred at 4 and 7 months into the study in males and females, respectively.
  • The effects described above occurred at the lowest doses studied (i.e., most observed effects were not proportional to the dose of treatment) but had a threshold effect at the lowest doses tested.
  • The effects described above occurred in residual levels of Roundup formulations found in contaminated drinking water falling well within authorized, regulated limits.

Study Highlights Inadequacy of Current Safety Testing 

No regulatory authority requires chronic (i.e., long-term) animal feeding studies to be performed for edible GMOs and formulated pesticides. The current approval process is based on animal feeding trials of only 90 days, which is an inadequate duration when chronic diseases in animals and humans do not usually manifest until mid-life.

Moreover, the newly emerging science of epigenetics demonstrates that endocrine systems can be seriously disrupted by the presence of chemical residues at concentrations as low as a few parts per billion. Chemicals like Roundup do not produce a linear response where the extent of exposure determines the biological response. Instead, residues well below legal limits cause serious disruptions; non-linear responses to glyphosate undermine the logic of an approval process based on MRL (maximum residue levels).

Lastly, the studies conducted by the biotech industry focus on one single active ingredient, such as glyphosate in Roundup, instead of the total chemical mixtures that are actually used in agriculture, thus under-representing the potential toxic effects on environmental pollution and human health.

Publication Buckles Under Biotech Industry Pressure, Study Republished Elsewhere

Sustained criticism and defamation by Monsanto scientists successfully forced the editor-in-chief of Food and Chemical Toxicology – A. Wallace Hayes – to retract the study in November 2013 in spite of rigorous peer review. The Séralini et al study was recently republished in Environmental Sciences Europe.

In the republished study, the authors explain the retraction was “a historic example of conflicts of interest in the scientific assessments of products commercialized worldwide… We also show the decision to retract [the original study] cannot be rationalized on any discernible scientific or ethical grounds. Censorship of research into health risks undermines the value and the credibility of science; thus, we republish our paper.”

The republished study contains extra material addressing criticisms of the original publication as well as the raw data underlying the study’s findings – unlike the raw data for the biotech industry studies that underlie regulatory approvals of Roundup, which are kept secret. The new paper presents the same results as before and the conclusions are unchanged.

Paper Subjected to Three Rounds of Scrutiny and Peer Review

Dr Michael Antoniou, a molecular geneticist based in London, commented, “Few studies would survive such intensive scrutiny by fellow scientists.”

The paper was first peer reviewed for its initial publication in Food and Chemical Toxicology, which passed with only minor revisions.

The second review involved a non-transparent examination of Prof Séralini’s raw data by a secret panel of unnamed persons organized by the editor-in-chief Hayes in response to criticisms of the study by pro-GMO scientists. In a letter to Prof Séralini, Hayes admitted  the anonymous reviewers found nothing incorrect about the results. However, Hayes argued the tumor and mortality observations in the paper were “inconclusive” which justified his decision to retract the study.

Even so, numerous published scientific papers contain inconclusive findings, including Monsanto’s own short (90-day) study on the same GM maize, and have not been retracted. The retraction was even condemned by a former member of the editorial board of Food and Chemical Toxicology.

The study passed a third peer review arranged by Environmental Sciences Europe, the journal republishing the study.

Dr Antoniou states: “The republication of the study after three expert reviews is a testament to its rigor, as well as to the integrity of the researchers. If anyone still doubts the quality of this study, they should simply read the republished paper. The science speaks for itself… If even then they refuse to accept the results, they should launch their own research study on these two toxic products that have now been in the human food and animal feed chain for many years.”

Dr Jack Heinemann, Professor of Molecular Biology and Genetics, University of Canterbury New Zealand, responded: “This study has arguably prevailed through the most comprehensive and independent review process to which any scientific study on GMOs has ever been subjected.”