Friday, October 05, 2012

Seralini, GMOs and the Scientific Method

A GP friend has drawn my attention to a study by Seralini et al  on the effect of Genetically Modified (GM) maize on rats which came out a few weeks ago.

The study divided rats into groups. One group got a normal maize, one group were given GM maize, one group GM maize with a dose of Monsanto Roundup (Glyphosate) and one group were given Glyphosate in their drinking water.

Result - the rats exposed to Glyphosate, and also those on the GM maize, developed tumours. The tumours were sex related (mammary and pituitary), and the male rats developed non-tumour problems in their liver and kidneys.

The key thing here is that the rats that just got GM maize reacted in the same way as the rats given Glyphosate. Why was this?

It is down to the way that Glyphosate works.  The point is that GM Roundup-ready maize is not affected by Roundup, so the crop can be sprayed to kill the weeds without affecting the crop.

As I understand it, Roundup does not just run off the leaves of the GM crop, nor is it excreted more quickly, nor is it destroyed in the plant. It gets absorbed, and then the plant's system locks it up out of the way. It is incorporated into the tissues, which means that anyone who eats the GM crop (provided it has been sprayed) will eat Glyphosate.  That is what I was informed. I have been unable to get a source for this information, and if anyone has any word to the contrary, I will modify this post accordingly.

Seralini's study has been criticised by scientist here.  Some of the criticisms are valid. I found the paper poorly written, the sample size was small, and the statistical analysis left much to be desired. More seriously, it seems that the paper was released to the press with an embargo, requiring that it should not be showed to other scientists. This is a violation of the principle that debate within the scientific community should precede debate in public.

A previous review of the literature on GM roundup ready maize  "concluded that glyphosate is noncarcinogenic". On the other hand, there is evidence of functional abnormalities in pregnant rat enzymes as a result of Roundup use.

The study has also provoked a hysterical attack in right wing sites like Forbes. And it has also been defended here.

It looks as if we could be seeing a re-run of the Pusztai affair, where a scientist who discovered an adverse effect on rats of GM potatoes containing the Bt gene was very badly treated. The response to Pusztai's work was wrong in terms of the scientific method.

One of the key criteria of scientific work is that it must be capable of being replicated by other workers. Instead of the hyper-criticism and defamation of a scientist who produces unexpected results, the correct scientific response should be to replicate the work, adapted and improved if necessary, according to the criticisms made.

Therefore the right scientific response to the work of Seralini should be to repeat his experiment, this time with more rats, to get more statistical power. Apologies to any animal liberationists who may be reading this.

In writing this, I am aware that I may be about to attract flak. The Green Party's sceptical stance on Genetically Modified Organisms (GMOs) has, ironically, been marked up  as "anti-scientific" by the pro-science movement that dominates political activism, and we find ourselves classified along with climate contrarians. This is mistaken. We Greens are not anti-science, but we are sometimes anti-technology, especially in the case of things that have the capability of adversely affecting the environment like GMOs, nuclear power and nuclear weapons. We are not against the knowledge, nor the acquisition of it, but against ill-considered technical application of the knowledge. Science and technology. There is a difference. We are not against the principle of the helical inclined plane, but we are against thumbscrews.

The paradox that greens are for climate science but against GM technology can be understood if it is placed in economic context. At least some of the defenders of GM foods are motivated by the aims of corporations who profit from the technology. Similarly, at least some of the defenders of the theory that CO2 cannot harm global climate are motivated by the desire to maintain the profitability of fossil fuel industry. Intense controversy is the result in both cases.

There is another central principle that needs to be underlined with GMOs. Their inclusion in food must be labelled, so that people can choose not to eat them. The disease causing effect of smoking could only be determined because we had a control group of non-smokers to match against the smokers. Similarly, we need a group of non-GMO consumers to act as a control group to find the health effects, if any, of GM foods. Unfortunately, this obvious need has been overridden, and most people are eating GM foods without knowing. The politicians who resisted the labelling of GMO foods are far more effectively anti-science than the Green Party.

In conclusion, Sertralini's work needs to be repeated carefully in a well designed trial if scientific method is to be used, and if the truth of GM technology is to be accurately determined.

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