Séralini’s rat-feeding trial (part 3)

Professor Gilles-Eric Séralini is a French scientist researching pesticides and GM (genetically modified, genetically engineered, GE) crops. A research paper from his team was published in 2012, retracted (withdrawn) in 2013 and republished in 2014. Here it is.

This is the third in a series of blog posts in which I comment on Prof Séralini’s study.

The study was a feeding trial in which rats (Rattus norvegicus) ate a GM maize (corn, Zea mays) called NK603 from Monsanto and Monsanto’s weedkiller Roundup (active ingredient glyphosate) which NK603 had been engineered to resist.

After the retraction, and before the republishing, an unnamed author at the USian non-for-profit Center for Media and Democracy’s PR Watch (‘Reporting on spin and disinformation’) told us about Prof Séralini’s original paper and the complaints against it. Here’s the PR Watch report.

‘For rats fed Roundup Ready corn (NK603) that was grown without any use of Roundup, “similar effects with respect to enhanced tumor incidence and mortality rates were observed.” The authors provide a hypothesis for why this occurred and conclude that “both the NK603 maize and R[oundup] may cause hormonal disturbances in the same biochemical and physiological pathway.”‘

The PR Watch report then summarises the criticisms made about the rat-feeding trial:

‘- Feed Quantities, Growth Rates, Rat Breed, and Statistical Methods
‘- Then “Why Aren’t North Americans Dropping Like Flies?”
‘- Statistical Significance’

This was proper scientific debate. A scientific team published their results; other scientists tried to knock down the study and its conclusions. The next stage should have been for another team to repeat the study. Good science is repeatable. But in this particular case, the paper was retracted.

The PR Watch report continues, ‘‘Michael Hansen [Senior Staff Scientist at Consumers Union] responded [during his testimony about labelling GM foods]…

‘”The two main criticisms of the Séralini et al. study were that they used too few rat per group and that they used a strain of rat (Sprague Dawley, aka SD) that is prone to mammary tumors as they age. Both criticisms are off base. This study took blood and other biochemical measurements on… the same number of rats that Monsanto took measurements on in their 90 day feeding study, which was published in the same journal eight years before the Séralini study. If ten rats is too small a sample size to demonstrate health problems, how come ten rats is a sufficient sample size to demonstrate no safety concerns? As for the strain of rat use,Séralini used the same strain [as in Monsanto’s]… feeding study. In addition, the same strain of rat was used in a Monsanto-sponsored two-year feeding study of rats fed glyphosate as part of a reregistration process in Europe. Why is use of SD rats bad when Séralini uses them, but ok when Monsanto and other biotech companies use them?

‘”However, both the French Food Safety Agency (ANSES) and the European Food Safety Authority (EFSA) have agreed with Dr. Séralini that such long-term safety assessment should be done on GE foods… On June 28, 2013 the European Commission [EC] announced they were spending 3 million Euros to fund a two-year carcinogenicity [cancer-causing] study on the same GE corn variety (NK603) that Dr. Séralini and colleagues used.”‘

In other words, Dr Hansen’s not impressed by the retraction. Nor am I. I applaud the EC’s decision to fund a new study which sounds like an attempt to repeat Prof Séralini’s science. As I write this in 2014, that study is underway.

The PR Watch report finishes with a summary of how Monsanto got the licence for the NK603 trait, then commercialised several maize varieties carrying it. Another two biotech giants – Dow and Pioneer Hi-Bred (a DuPont subsidiary) – commercialised their own maize varieties carrying the NK603 trait.

If our UK Secretary of State for Environment Food and Rural Affairs, Owen Paterson, gets his way we’ll see maize NK603 here in England. Mr Paterson, will you wait for the results of the EC study, repeating the rat-feeding trial? Or will you just charge ahead?

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About argylesock

I wrote a PhD about veterinary parasitology so that's the starting point for this blog. But I'm now branching out into other areas of biology and into popular science writing. I'll write here about science that happens in landscapes, particularly farmland, and about science involving interspecific interactions. Datasets and statistics get my attention. Exactly where this blog will lead? That's a journey that I'm on and I hope you'll come with me.
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One Response to Séralini’s rat-feeding trial (part 3)

  1. Pingback: Séralini’s rat-feeding trial (part 4) | Science on the Land

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