1.Genetically-modified organisms in news again
2.Sprague Dawley rats frequently used in long-term toxicity/carcinogenicity studies
NOTE: Item 2 shows that the Sprague-Dawley (SD) rat used by Seralini far from being the "wrong rat", as Seralini's critics endlessly repeat, is actually the standard for Monsanto's 90-day tests on GMOs and for industry and independent 2-year chronic toxicity and carcinogenicity tests on chemicals. Peer-reviewed data also show, incidentally, that the SD rat is an excellent human-equivalent model for predicting cancer in humans in long-term (2-year) studies.
1.Genetically-modified organisms in news again
Professor John Moore
Sunday Mail (Zambia), October 9 2012
*Two weeks ago, the Sunday Mail produced an exclusive investigative story which showed how unsafe genetically-modified organisms (GMO) maize is on rats as they developed tumours after being subjected to GMOs. In this opinion write-up, Jesuit Priest and a Professor of Biology John Moore shares his own findings about GMOs but the jury is still out on the safety or unsafety of GMO consumption because of their various effects.
A VERY important study on genetically-modified-organisms (GMOs) maize was published on September 19, 2012. It reported that laboratory rats fed with GMO maize (NK603) developed fatal cancer tumours after a year.
Similar results were also obtained for those rats exposed to the popular weed-killer 'Roundup' in their drinking water, even at the very low concentrations permitted by the regulatory agencies.
The reactions in the media to this study varied from scare headlines like "Yes, GMOs are poisons", to highly critical and sometimes unfair and inaccurate criticisms of the scientific paper reporting the results.
It was obvious to me that some of the critics had not even read the research paper for they made statements about it that were patently untrue.
If these findings are valid, we Zambians should be so grateful for the stand taken by our late president Levy Mwanawasa against the importation of GMO maize. In South Africa 77 percent of the maize grown is GMO and in August this year, Kenya authorised the importation of GMO crops.
In view of the sometimes very strong statements claiming that the conclusions drawn from this study are invalid, I would like to look at the paper from the scientific point of view, fully conscious of these adverse criticisms.
It is obvious that this question is very important for us here in Zambia and surrounding countries where maize is the staple food for so many people.
In 2009 the European Food Safety Authority (EFSA) confirmed its previous authorisation for the import and processing of GMO maize NK603 in countries of the European Union (EU). Now they added authorisation for the cultivation of the plant.
Their report concluded with the words "NK603 maize is as safe as conventional maize". They based their judgment to a large extent on a feeding experiment where laboratory rats were fed for 90 days on diets containing NK603 (Hammond et al, 2004). No obvious harmful effects appeared which could be attributed to the GMO maize.
Professor G. Séralini and his team at the University of Caen in France considered that this 90 day period was too short, so they repeated the feeding experiment allowing it to run for the normal lifetime of the rats two years.
They used the same type of rats and the same concentration of GMO in the diet as in Hammond study. In addition they added some extra treatments, notably adding "Roundup" to the drinking water in three concentrations.
The results are really shocking. At the end of the earlier 90-day study there had been no observable differences between the rats fed with some GMO maize and those that ate the normal natural maize, but as Séralini comments in regard to his own study, "After less than a year of different GMO maize menus there was carnage among our rats to a degree I had not imagined."
The rats fed with additions of GMO maize or with the weed-killer Roundup were dying at a rate two to three times higher than the controls, the females mostly from cancer of the breasts and males from liver and kidney cancer.
Within a day of the release of these results, very many objections against the validity of the study began to appear on the Internet, some of them from so-called 'experts' in the scientific world but others just joining in a good internet debate.
Many of the objections are just silly, obviously aimed at general readers without a scientific background. For example: "It would appear the authors have gone on a statistical fishing trip" or more arrogantly "to be honest, I am surprised it was accepted for publication".
"Why aren't the North Americans dropping like flies? GM has been in the food chain for over a decade over there and longevity continues to increase inexorably" The simple answer is "they do not eat much maize in comparison to a typical Zambian."
However, two of the more serious criticisms disturbed me from the scientific point of view before I had managed to download and read the research paper itself.
These were: (1) the number of rats in the control group was just 10 for each sex, the same number of rats as had been assigned to each treatment. This seemed rather small and was criticised by many of the 'experts'; and (2) the use of a tumour-prone strain of laboratory rat (the so-called Sprague-Dawley strain) was strongly criticised.
It was well-known that this strain of rat often developed cancerous tumours toward the end of its life span of about two years. It was claimed that the results reported by Séralini and his colleagues could easily have arisen just by chance variation.
Monsanto company, who developed the Roundup weed-killer as well as the Roundup-resistant GMO maize immediately posted 10 technical criticisms of the work on the Internet, some from the points of view of experimental design, some criticising the presentation in the published paper.
I would more or less agree with these criticisms but they all miss (or ignore) the main point of Séralini’s work. It confirmed the previous findings of Hammond which showed that no negative effects of the GMO-enriched diet were detectable externally during the first three months.
Séralini's work showed clearly that the bad effects of GMO maize (or Roundup) in the diet only began to appear in the early months of the second year.
Therefore, the standard regime previously used to test for harmful effects (a 90 days feeding trial) was practically useless for testing whether the GMOs were harmless or not; the trials must extend for at least 18 months if they are to pick up any cancerous growths or other bad effects of the GMO diet.
Almost all the scientific critics complain about the statistics (or lack thereof), especially for the data reporting on the death of rats, sometimes occurring naturally as a result of the tumours, sometimes being painlessly killed by the researchers for ethical reasons.
However, the results are so obvious that anyone familiar with the handling of numerical data would see immediately that there was a significant effect that could not conceivably be attributed to a random event in a tumour-prone strain of rats.
I did a simple Chi-squared for both the male and the female mortality data presented in figure.1 for the observations made on day 550; the chance of such a "carnage" (to use Prof. Séralini’s term) occurring purely by chance was much less than 1 in 1,000.
There was no need to clutter up the paper with a series of standard statistical tests when the diagrams made the situation perfectly clear for those "who have eyes to see".
It might help to bring home the importance of these findings if we express them in human terms. Let's presume that the S-D laboratory rat is a suitable animal for testing the effects of poisons on humans.
We could also presume that a two year old rat would be the equivalent of a 70 year old human, both approaching a natural death; a rat 90 days old would be the equivalent of a nine-year old child and a 550 days old rat would correspond to a 53 year old human.
Now human cancers normally do not show as tumours in a 9-year-old child but often start appearing in middle age. Therefore it is essential to prolong feeding experiments with rats for at least 18 months (550 days) before being able to say confidently that "NK603 maize does not cause cancers in humans in their 50’s. In fact it is as safe as conventional maize".
In addition to recording cancerous growths in the rats, Séralini's team also carried out a large number (48) of biochemical analyses in an effort to find out why the GMO maize and Roundup were causing such 'carnage'.
They analysed the results using sophisticated multivariate analysis (far from being a "fishing trip", whatever that may mean!).
Only two of these measurements were significantly different for the GMO-fed rats as compared with the controls (GMO-free diet). On the basis of these results the authors speculate on the possible biochemical pathways that might have been affected.
They suggest that the hormonal system of the rats was first affected. This is normal procedure in any biological paper one needs to throw out hypotheses that can be tested by other people working in the field.
Most of the valid criticisms of the paper refer to these efforts and not to the shocking and incontrovertible fact that feeding on GMO maize causes premature cancer growth in rats so that by day 550 large numbers were dying from various kinds of cancer.
If we postulate that a similar process could take place in humans also, that would mean that humans who had been eating large quantities of GMO maize would develop cancers around the age of fifty.
No wonder the French news media describe it as "Un Scandale" outrageous!
That is why several European countries are considering banning the import and growing of GMO maize NK603 and 'eco-NGOs' in South Africa have petitioned the government to declare a moratorium on this NK603 Roundup resistant maize.
The author is an Irish Jesuit Priest. Between 1984 and 1990 he was Professor in Biology Department of the University of Zambia and between 1960-1983 he was Professor of Botany, University College, Dublin, Ireland. He was also at Arrupe College, Harare, Philosophy of Science and environmental Ethics between 2004 and 2010.
2.The use of Sprague Dawley rats that are prone to high natural background cancer-rates
(Extracted from the European Network of Scientists for Social and Environmental Responsibility (ENSSER) Statement on Seralini et al. (2012) http://www.ensser.org/fileadmin/files/ENSSER-Comments-Seralini-etal2012.pdf )
These rats are used routinely in such studies for toxicological and tumour-inducing effects, including those 90-day studies by Monsanto as basis for the approval of NK603 maize and other GM crops (Hammond et al., 1996, 2004, 2006; MacKenzie et al., 2007). Most critical commentators of the Seralini et al. study failed to inform their readership about this fact arguing that the tumours usually develop after 3-4 month. Seralini at al. used this rat strain to keep their study design as comparable to Monsanto's as possible. Had they used another rat strain and shown adverse effects, the relevance of their results probably would have been challenged on that basis, i.e. the use of different types of rats.
Contrary to the broad claims of commentators, Sprague Dawley rats are also frequently used in long-term toxicity/carcinogenicity studies:
1. The National Toxicology Program of the U.S. Department of Health and Human Services uses this strain in its 2-year studies, uncontested.
2. A brief, quick and still preliminary literature search of peer-reviewed journals revealed that Sprague Dawley rats were used
- in 36-month studies by Voss et al. (2005);
- in 24-month studies by Hack et al. (1995), Klimisch et al. (1997), Minardi et al. (2002),
Soffritti et al. (2006) and Gamez et al. (2007);
- in 18-month studies by Lee et al. (2010); and
- in 12-month studies by Perry et al. (1981), Conti et al. (1988), Morcos & Camilo
(2001), Flamm et al. (2003) and Gutierrez et al. (2011).
Four of these studies had been published in Food and Chemical Toxicology.
1.Genetically-modified organisms in news again