Media Release: Rebuttal of GM Study Critics
GM & ROUNDUP LINKED TO TUMOURS IN RATS
Consumers have been urged to make up their own minds as controversy rages over European findings linking tumors in rats with genetically modified corn and the world’s top-selling herbicide, Roundup. The paper, “Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified corn”, published by the scientific journal Food and Chemical Toxicology, reports on a study led by molecular biologist and endocrinologist Professor Gilles-Eric Seralini, of the University of Caen, France.
The first animal feeding trial studying the lifetime effects of exposure to Roundup tolerant GM corn and Roundup shows that levels currently considered safe can cause mammary tumours and severe liver and kidney damage, and can lead to premature death in laboratory rats.
The rats were fed on a diet containing NK603 Roundup tolerant GM corn, or given water containing Roundup at levels permitted in drinking water and GM crops in the US. The control group had a standard diet.
Pro-GM scientists have attacked the study for the type of rats used, the size of the test sample, and the age of the rats. But Scott Kinnear, director of the Safe Food Foundation, says this is reminiscent of the reaction of some scientists and doctors to early concerns about tobacco, asbestos, and some pharmaceuticals.
“Consumers need to be wary of these gang-tackling, synchronised, rapid-response attacks by scientists, many of whom have pro-GM conflicts and frequently comment outside their area of knowledge. For example, the soil expert who criticises the findings of a geneticist,” Mr Kinnear said.
“The rats are the same breed used by the GM industry to test their products. The difference is that they usually do a 90-day feeding trial to satisfy regulators, whereas this study, which ran for two years, found tumours appears at 120 days and peaking at 600 days.
“The length of the study – the lifetime of a rat – allows comparison with the effects on humans over their lifetime.
“Critics are correct that rats at two years are more prone to cancer but rats which consumed GM corn and/or Roundup had 200-300 per cent more large tumours than the control group. The difference is significant, regardless of the age of the rats.
“As for the size of the test sample, critics need to read the study – yesterday several simply misquoted the numbers in the Seralini paper. If they can get such a basic fact wrong, it raises doubts over the rest of their argument.”
Summarising the Seralini findings
Up to 50% of males and 70% of females died prematurely (before deaths could be put down to normal aging) compared with only 30% and 20% in the control group.
Across all treatments and both sexes, researchers found treated rats developed 2-3 times more large tumours than the control group, defined as 17.5mm in females and 20mm in males.
By the beginning of the 24th month 50%-80% of females in all treated groups had developed large tumours, with up to three per animal. Only 30% of the controls were affected.
The first large detectable tumours appeared after four and seven months in males and females respectively but only after 14 months in the female control group and 23 months in a control male. However, the majority of tumours were only detectable after 18 months.