Many of the initial attacks came from a group of scientists who seem to be orchestrated by the industry lobby group the Science Media Centre. In fact what the BBC - in one of its increasingly frequent lapses of integrity concerning the GM issue – called a “furore” were comments from a couple of this rent-a –quote crowd that were recycled around the media.

 Dr Michael Antoniou, a reader in molecular genetics at Kings College, London and a member of Criigen – the Committee of Research & Independent Information on Genetic Engineering – has mounted a vigorous defence of the study.

Breed of rat

This had been criticised as being prone to tumours. But according to Antoniou this breed ” was used in the original glyphosate toxicity studies,"

"In addition, many studies – including many from industry – on GM foods use SD rats. Based on this history of use, it was appropriate to use this strain too. If it was the wrong strain to use here then it was wrong in many previous GM food safety feeding studies conducted by industry and upon which marketing approval was granted."

"The key is that there were both quantitative and qualitative differences in the tumours arising in control and test groups. In the former they appeared much later and at most there was one tumour per animal, if at all.

"In the latter case, the tumours began to be detected much earlier (4 months in males; 7 months in females), grew much faster and many animals had two or even three tumours.

"Many animals in the test groups had to be euthanised for welfare legal reasons due to the massive size of the tumours; none of the control animals had to be euthanised but died in their own time. One should not ignore these biological facts."

The rat’s diet

“The animals had unrestricted access to food and water, and there was no difference in consumption or drinking levels between controls and test groups, apart from the group exposed to the highest Roundup concentration drank less.”

Numbers and control groups

According to Dr. Antoniou the two-year experiment followed international OECD guidelines. The rodents in the experiment were divided into 10 groups of 20 animals, with nine of those groups exposed to Roundup or NK603. "Standard practice is for the control group to be matched in size to the experimental groups. The experimental groups were 20 animals and therefore the control group should be 20 animals.

From the 20-animal control, you can get a measure of tumour frequency in the control group. You don't need to look at hundreds of animals. This is in line with studies done by others – including industry.

"The key thing is that there are big differences between the tumour frequencies in the control and the experimental groups.  Claims that the results are just the result of random variation in a rat line that has a high frequency of tumours are not valid.”

Number Crunching

The basic criticisms made by the ‘rent- a-quote’ scientists and statisticians are that the statistics were hokum - made by somebody with a limited understanding of statistics.   That sort of criticism is self- defeating, because their comments certainly reveal a total lack of understanding. The study has its faults, and all studies do, but the coverage of it is certainly flawed. The authors of this paper appear to be doing a competent analysis of the data that they have. 

The graphs are fairly poorly presented but that has nothing to do with the worth of the underlying study. This new paper intentionally follows the form of the (shorter term) study that was used by Monsanto to prove that their maize was safe.

Small sample sizes are common with this sort of study, note the industry study that they are attacking wasn't much larger, and this is because the natural incidence of tumours in rats is quite low; no science at all could be done if we had to rely on studies of 100,000 rats. Media needs to understand this, and take this research seriously.

Number Crunching
The basic criticisms made by the ‘rent- a-quote’ scientists and statisticians are that the statistics were hokum - made by somebody with a limited understanding of statistics.   That sort of criticism is self- defeating, because their comments certainly reveal a total lack of understanding. The study has its faults, and all studies do, but the coverage of it is certainly flawed. The authors of this paper appear to be doing a competent analysis of the data that they have. 
The graphs are fairly poorly presented but that has nothing to do with the worth of the underlying study. This new paper intentionally follows the form of the (shorter term) study that was used by Monsanto to prove that their maize was safe.
Small sample sizes are common with this sort of study, note the industry study that they are attacking wasn't much larger, and this is because the natural incidence of tumours in rats is quite low; no science at all could be done if we had to rely on studies of 100,000 rats. Media needs to understand this, and take this research seriously.

Key points

Much of the criticism misses the key points of the research; tumours only appeared a month after all previous trials demanded by the regulators would have ended – calling into question their rigour.

The differences between all treated groups and the control are significant and demand investigation.

The GM but non-roundup treated maize also caused health problems. It was not therefore “substantially equivalent” to non GM maize and highlights that there might be a fundamental problem at the heart of GM safety assessments.

A dark heart because no-one in government has wanted to put light on it before but now they have to.

http://research.sustainablefoodtrust.org/wp-content/uploads/2012/09/Response-to-criticisms.pdf