The research − led by Professor Giles-Eric Seralini at the University of Caen− claimed that rats exposed to Roundup (glyphosate) and/or its Round-up resistant maize, NK603, developed cancers in the form of mammary tumours plus liver and kidney damage.
Half of the males and 70% of females died prematurely, compared with only 30% and 20% respectively in the control group, claimed the researchers. Their research was published this week in the Food & Chemical Toxicology Journal.
But leading scientists have disputed the findings. Dr Wendy Harwood, senior scientist, John Innes Centre, said: "The full data set has not been made available, but the findings do not contradict previous findings that genetic modification itself is a neutral technology, with no inherent health or environmental risks.”
Professor Maurice Moloney, institute director and chief executive, Rothamsted Research, said: "Although this paper has been published in a peer–reviewed journal … there are anomalies throughout the paper that normally should have been corrected or resolved through the peer-review process.”
“For a paper with such potentially important findings, it would have been more satisfying to have seen something with a more conventional statistical analysis.”
David Spiegelhalter, Winton Professor of the Public Understanding Of Risk, University of Cambridge, said: "In my opinion, the methods, stats and reporting of results are all well below the standard I would expect in a rigorous study – to be honest I am surprised it was accepted for publication.”
But Dr Michael Antoniou, molecular biologist at King’s College London, defended the quality of the French study. Antoniou told a national newspaper: “I am shocked by the extreme negative health impacts.
“It shows an extraordinary number of tumours developing earlier and more aggressively in female animals.”
Meanwhile, regulatory authorities said they needed more time to study the results. A spokesman for the Food Standards Agency told FoodManufacture.co.uk: “This is a complex paper and we will need time to consider the way the study was carried out, the results of the study and the way the results have been analysed for significance.
“The safety of the GM maize used in this study was evaluated rigorously before it was approved in the EU. We will consider any new information or research to assess whether there may be any implications on the safety of approved GM products.”
The European Food Standards Agency (EFSA) said: ”EFSA will consider the paper’s relevance taking into account the available scientific evidence including recent studies assessing, over a sustained period of time, the potential toxicity of foods derived from GM crops.”
The Institute of Food Science & Technology (IFST) told FoodManufacture.co.uk more research was needed. Its chief executive Jon Poole said: “Food scientists and technologists can support the responsible introduction of GM techniques provided that issues of product safety, environmental concerns, information and ethics are satisfactorily addressed.
“The IFST considers that they are being addressed, and need even more intensively to continue to be addressed. But scientifically, we have concerns about this report. One cannot make a ‘blanket’ judgment about GM foods or crops as this report appears to do, being on a single strain of GM maize - NK603."
Meanwhile, a spokesman for Monsanto told FoodManufacture.co.uk: “We will review it [the study] thoroughly, as we do all studies that relate to our products and technologies.
“In the past, similar claims made by the same author were systematically refuted by peer-reviewed scientific papers as well as by the European Food Safety Authority.”
He added that the European Commission had funded research from 130 research project involving 500 independent research groups over 25 years, concluding that “There is, as of today, no scientific evidence associating GMOs with higher risks for the environment or for food and feed safety than conventional plants and organisms.”