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Asked by ljrn42 to Andy, Cathie, Jules, Les, Ricarda on 24 Jun 2012. This question was also asked by isabelnoble.
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Cathie Martin answered on 24 Jun 2012:
GM is a technique used to develop new traits in crops. Therefore one cannot consider the long term effects of GM in a generic sense. The long term effects of consuming any food product generated using GM technology will depend on the particular trait that has been engineered.
GM crop plants have been around in the world since the end of the 1980’s and there have been no substantiated cases where consumption of a food derived from GM plants has caused adverse effects in humans, as a result of the genetic modification involved. Even for an epidemiological study this is a reasonable period of time. All GM crops destined for foods are tested for toxicological and allergenic effects, and risk assessment is undertaken to assess the likelihood of later undesirable effects. GM crops that do not pass the ‘no toxicity, no allergenicity’ tests, are of course, never released. Scrutiny is far in excess of that required for registering a new plant as a food, or for introducing a new variety of an existing crop. Many of the next generation of GM crops will offer consumers significant advantages in terms of nutritional quality, and consumption of these foods can be shown to reduce the risk of chronic disease. How long should we wait before foods with demonstrably beneficial effects on health are made available to the public?
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Les Firbank answered on 24 Jun 2012:
All GM crops grown in Europe are studied for their environmental effects, and the companies have to monitor the crops, and report what has been seen. Permission to grow GM crops in Europe can be withdrawn if any harm is seen.
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Julian Little answered on 25 Jun 2012:
Hi ljrn42, an interesting question and one I used to get asked quite frequently. The simple answer is how long is ‘long’. This technology has been around for over 20 years – is that long enough? If that isn’t long enough, why is it more than sufficient for ‘conventional’ breeding where little or no safety testing is required? How about the stat that there have been nigh on 3 trillion meals containing GM ingredients eaten without one substantiated food issue? Or the fact that the European Commission (which is not known for a pro-GM stance) published a report detailing the 120 projects it had funded over the last 25 years with 500 research groups (http://ec.europa.eu/research/biosociety/pdf/a_decade_of_eu-funded_gmo_research.pdf ). It’s conclusion? “That biotechnology, and particularly GMOs, are not per se more risky than, eg conventional plant breeding technologies”. But we will continue to look for problems and report on then as and when they arise. Because in the end, “long term” is for ever!!
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Ricarda Steinbrecher answered on 27 Jun 2012:
None to my knowledge. GM food is not even labelled in most countries, thus long term health effects on humans cannot be monitored or identified. Short term animal feeding trials up to three months have been undertaken, or a little bit longer in a very few cases. These trials already indicate problems. In spite of those indications, no long term multi generational multi animal feeding trials are being undertaken. One problem is that there is no agreed standard for such feeding trials, thus comparisons are often not easily possible, and findings might seem contradictory. I have been told by colleagues that regulatory rules for pesticides or drugs are: 3-month tests with 3 mammalian species, then with a mammalian for 1 year and yet another for two years.
No such rules have been set for GM food, but I am going to check with a colleague who is working on the issue of standards, such as feeding trial standards, and will let you know if I find out more with regards to GM. We have to remember though that long term feeding trials on animals may still miss potential long term health effects that may occur in humans.
Comments
dingo commented on :
I am pretty shocked at the replies here from the scientists. There is only one way to find out if a GM food has the unexpected toxic effects that FDA scientists warned could occur before they were released onto world markets: long-term toxicological testing in controlled animal feeding trials, which should then progress to human trials on volunteers. This is not done. All that is done routinely is 30-90 day feeding trials on rodents, conducted by the GM companies that want to release the GM food. These trials have nevertheless shown toxic effects but have not been followed up with longer-term studies. Séralini, G. E., R. Mesnage, et al. (2011). “Genetically modified crops safety assessments: Present limits and possible improvements.” Environmental Sciences Europe 23(10).
boo_lewis commented on :
dingo, if you’re interested in safety data there’s a really interesting website called GMO pundit (http://gmopundit.blogspot.co.uk/) by a guy called David Tribe who publishes links to every single safety study about GM crops, along with commentary in a sort of Ben Goldacre style. It’s really worth a read.
dingo commented on :
Thanks but what worries me about this site is that it cites studies that Tribe says show safety, which actually show harm. You have to look at the actual studies to find this out. Also a lot of the studies he cites are not safety studies at all but compositional studies or feed conversion studies!
fern commented on :
I am also rather shocked at these replies by the experts. They don’t seem particularly, well, scientific to me!
The claim that people have been eating GM foods for years and no harm has been seen yet is completely unsatisfactory. How would we know or be able to make any possible causal connection in such a case, particularly if our concept of harm or negative impacts is broader and more subtle than bodies in the streets? We are not dealing here with an experiment with controlled parameters! If eating GM corn was leading to increased allergies amongst susceptible members of a population, how would we know that? Would those eating it know they were eating it? Would they tell their doctor that they were eating it? Would their doctor think to question whether their allergy might be related to GM corn? No, they would not. This means we could have been eating it for years, experiencing negative effects and still not know it.
So what about the experiments that have been done? The experts seem to place a lot of faith in the studies submitted during risk assessment and regulatory evaluation, but as Dingo points out above, most of these experiments are done by the companies promoting the technology and the timeframe used is typically no more than 90 days for rat feeding studies (note! no human trials!). This is typically sufficient for regulators. Anyone who has reviewed an actual dossier on GMO risk assessment can not help but be shocked at the poor quality and limited quantity of the science that has been done before these organisms receive approval for commercial release. While the experts may wish to reassure us that science is done, risk assessment performed, and regulatory practices in place so everything is under control, the key question is really what is the quality of this science, and in terms of understanding long term health questions, and particularly environmental impacts, it is unbelieveably poor, to say the least!
As for monitoring…monitoring is, as pointed out above, typically done by companies selling the technology, and if not by them, they will ask farmers to report to them any problems they may observe. This is clearly manifestly insufficient for detecting potential negative impacts – especially since baseline data that can be used for comparison is also typically missing.
In short, I would say that the effort and funding being directed towards independent biosafety research on GMOs generally is extremely low and into long term effects, sadly even lower.
Note that this does not necessarily mean that there are any long term risks! Just that we are not well placed to identify them if they do exist.
joseph110 commented on :
Some interesting peer-reviewed toxico studies on GM foods here (section 3): http://earthopensource.org/index.php/reports/58-gmo-myths-and-truths
Also mentioned are some reviews of the state of the literature by independent scientists–they do not make for reassuring reading.