Here we go again

Polarised views on GM maize (Illustration: Forbes)

On 19 September 2012, a scientific study was published on-line later to appear in print in the scientific journal Food and Chemical Toxicology. It got an immediate negative response from a large part of the scientific community for using a deficient methodology, but not before receiving strong support from the activist community. The reason for the latter being that it had been circulated to supporters before being published. Sounds intriguing? Here are the facts as much as they can be discerned through the haze of polarised opinion.

The study in question was undertaken by Séralini and co-workers from the universities of Caen and Verona. The French professor Gilles-Éric Séralini is no stranger to controversies and he is well-known for being furiously anti-Monsanto. And here he was, the lead author of a study to test the effects of feeding rats Monsanto’s NK 603 GM maize and the Monsanto herbicide glyphosate separately or in combination. The group set out to prove the need for long-term mammalian toxicity studies before approval of new GM plants. Currently, only 90-day rat feeding trials have been conducted by the biotech industry. The group kept the rats in the trial for two years to prove their point.

The NK 603 GM maize has been genetically modified to be resistant to the herbicide glyphosate sold under the commercial name Roundup. The study claimed that rats fed on GM Maize suffered mammary tumours, and severe liver and kidney damage at double the rate of rats in a matched sample fed non-GM maize – 50% of males and 70% of females died prematurely, compared to 30% and 20% in the control group. The authors concluded that the results could be explained by non linear endocrine-disrupting effects of Roundup, but also by the over expression of the transgene in the GM maize and its metabolic consequences.

The response from anti-GM supporters was immediate. Care2, of which I am a proud member, started a petition to request that the European Union immediately ban all GM food products. There could be many legitimate reasons for not growing GM plants, particularly glyphosate tolerant plants. To all actions there is always a reaction. And to indiscriminately use just one herbicide will meet with a reaction from nature. The weed we’re trying to destroy will fight back and will itself acquire herbicide tolerance. But so far there is very little evidence, if any at all, that GM plants are dangerous if consumed by humans. I was thus very disappointed by the knee-jerk reaction from Care2. I had expected better as a scientist.

The activist response was followed almost immediately after publication of the study by an outcry from many scientists as well. They claimed that you cannot study chronic effects by using so few control animals. The rat strain used was prone to spontaneous cancer development and if left to survive for more than two years might have a 70% cancer incidence in the untreated group. The statistical methods used were not appropriate for this kind of study. And presentation of the findings were selective and impossible to interpret. The European Food Safety Authority was officially asked to provide a comment on the study and wrote an open letter to the authors asking for further information so that they could provide a considered opinion. This was refused by the authors.

So now we have stalemate. The views are extremely polarised. If the authors would have liked to be taken seriously they should have been more careful in their study design. They had previously made clear on what side of the debate they stand and should have expected this reaction from other scientists. Or maybe this was exactly what they were after. They have certainly got enough publicity already and preached for the converted. But will the results contribute to an honest debate? It doesn’t seem so at this stage.

About food science guru
A public health veterinarian and past professor in food safety with life-long experience at national and international levels. Instrumental in assessing public health exposure to beneficial and hazardous chemicals and microorganisms as part of risk assessments.

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