Bad Science: The French GM maize cancer study

You may or may not have already heard about the recent study published in the “Food and Chemical Toxicology” journal, linking genetically modified (GM) maize with aggressive tumour formation and premature death.

Yes, the stuff of nightmares if you are a proponent of GM foods as a potential solution to world hunger. Or if you’re just worried about what goes into your food (which you should anyway). On the other hand, great stuff if you are the Daily Mail! However, this study is severely flawed.

I’ve been following the aftermath of this publication with interest, as I find this subject fascinating -I frequently find myself awestruck by the advances in genetic engineering, and I believe that such technology should certainly be on our arsenal against diminishing food supply -honest question: what else is on that arsenal?

Much more qualified people than me have already reported on this, so I will just be lazy and point you to a few such articles.

First, a brief overview of the “study”:

This two-year animal research included 200 rats (100 of each sex) divided across 10 groups. Three groups each containing male and female rats were fed different concentrations of a GM maize crop. Another three groups were fed GM maize that had been treated with the herbicide “Roundup”. These six groups were then compared with one control group of rats fed untreated, non-GM maize

Then, a list of some typical bad science stuff in this “study”:

  • Inadequate controls: “for tests of this duration, the OECD recommends at least 20 rats of each sex per group for chemical-toxicity studies, and at least 50 for carcinogenicity studies” not 10 for each sex group in this study!

    Further, the rat line selected is notorious for developing spontaneous tumours, with a probability of surviving for the two year duration of the study less than a third for males, and less than half for females.
  • The authors reported the cancer outcomes as the major finding, even though the experiments have not been designed to identify differences in tumour incidences.
  • Some pretty bad conflicts of interest there. The main author, Gilles-Eric Séralini, is a well known opponent of GM organisms (GMO) in general, and I believe the publication of this paper coincided with the publication of a documentary and a book about his work (confirm anyone?)
  • As many have pointed out, there does not seem to be a dose-response, which makes one wonder how much of the outcome was actually due to the toxicity of the rat diet or pure chance…

But the thing that I found most arrogant and ludicrous, was this:

Journalists often receive embargoed journal articles, and standard practice is to solicit independent assessments before the paper is published. The agreement for this paper, however, did not allow any disclosure and threatened a severe penalty for non-compliance: “A refund of the cost of the study of several million euros would be considered damages if the premature disclosure questioned the release of the study

In other words: here’s my paper; you cannot get any independent experts’ opinion before reporting; also, if you write anything questioning my paper you may end up owing me several million euros

This is not proper science reporting, and the whole story is covered in mysticism, questionable methodological quality, and strong idealogical biases. On the whole, this is bad science.