GMOs in Food Production: Evidence of Risks
Briefing Paper / Soil Association 24may01
1. Introduction
The Soil Association believes that genetically modified foods (GMOs) should be
prohibited from all food production. This is because their use goes against the
Association's principles for safe and sustainable agriculture, including:
· the use of natural processes
· production to the natural capacity of the crop, livestock and environment
· a systems approach to farming (recognising that complex interactions occur
between different aspects of the farming system)
· a precautionary approach to safety issues
While this stance has often been referred to as anti-science, it is actually based on scientific evidence. The evidence that has emerged on GMOs over the last couple of years shows that there are several clear risks to human health and the environment.
2. Current Scientific Understanding of the Risks
Contrary to the public statements by the biotechnology companies that genetic
engineering is a precise technique and simply an extension of traditional
breeding methods, the process is actually significantly different. The outcome
is inherently random and introduces many novel risks:
· Random location of the inserted genes: when genetic engineers create GM crops, they have no means of inserting the gene in a particular position. The gene ends up in a random location in the genetic material and its position is not usually identified. But, genes do not work in isolation; they interact with each other. This means unintended effects will occur. As these cannot be predicted, the side effects cannot all be identified and tested in advance of marketing. There are already several examples of such undesired effects being identified in the US after approval (eg. GM cotton with deformed cotton bolls; increased lignin in GM soya).
· Lack of normal control over the genes: all genes are present in every cell of an organism. But they do not function the whole time or in every cell. In nature, genes are controlled to ensure that they only operate in the relevant part of the plant and at the necessary time (eg. gene for flower opening would only operate in the flower bud in spring). This control is believed to be from a mixture of the other genetic material (only a small part of the genetic material of an organism comprises functional genes) and the gene's local environment in the organism. But because little is known about this, GMOs have no equivalent control. So the genes usually operate the whole time in every cell, including the part destined for consumption.
· Most genes have several functions: Genetic engineers have assumed that each gene has only one function and this has been the basis of genetic engineering to date. The recent discovery that humans have only c.30,000 genes to produce the c. 250,000 proteins in the human body has showed that this assumption was wrong: most genes actually have several effects. But, it is not yet known how these different functions are controlled. In other words, it is not known how to artificially determine a single function of a gene, without other undesired effects.
The random position and lack of control of the gene's functions and how it interacts with other genes, means side effects are generally inevitable. These could change absolutely any character of the plant and, moreover, they are unpredictable in advance. These changes may be evident immediately or only in response to the environment (eg. the increased lignin in GM soya was only evident in hot weather when the stems started splitting).
· Horizontal gene transfer: Along side the main gene, genetic engineers usually introduce other material into the organism. These have the role of inserting the gene, activating it, and identifying the successful transfers. Any of these parts can be of viral or bacterial origin. Viral parts are often used since viruses are adept at inserting their genetic material into other organisms ? that is how they reproduce. But, this introduces the potential for "horizontal gene transfer" to occur: the genes transferring out of the GMO and into other organisms. Bearing in mind the nature of viruses, it can be assumed such transfers will occur much more frequently than would occur naturally for the non GM organisms. Indeed, evidence for this effect already exists from laboratory and field research on GMOs. But it is not known at what level this effect will occur, even what at order of magnitude. And the safety implications are certainly not known…
All the above explains that just because a gene is 'safe' in the original organism, does not mean it is 'safe' in a GMO. It is not the gene's intended function that creates all these problems, but the process of genetic engineering. This is something the biotechnology companies have yet to admit. Neither their public information nor their testing procedures recognise these fundamental problems with the process, because the companies know that this would call into question the whole technology, not just certain individual GMOs.
· Allergenicity to novel proteins: GM technology often involves the production of novel substances. allergic reactions to the novel proteins have been forecast by many scientists, including several in the US Food and Drugs Agency. If such substances are present in food, people would be regularly exposed to this risk. For example, this concern emerged in 1995, when experiments found that a GM soya with a brazil nut gene would cause allergic reactions.
· Herbicide resistant plants: toxicity of the herbicide: the creation of herbicide resistant plants allows the use of herbicides on the growing plant that would not normally be possible. This means people could be exposed to residues that they would not normally be. The consequences have not been properly considered so far. For example, the GM forage maize, Chardon LL, was approved for commercialisation by the Government, despite risk to human health from this aspect. The relevant herbicide in this case was glufosinate, a neurotoxin and a teratogen (damages embryoes). Apparently, there is a 10% reconversion rate of the degraded herbicide back to the original toxic form in the gut.
· No reduction in pesticide use: contrary to intentions, pesticide use on several GM crops is often greater than on the non GM crops. For example, Round up ready soya is often resulting in a greater use of herbicides; and, pesticide treatment has not reduced with some GM pest resistant plants.
· Effect of processing GMOs: it is often stated by the biotechnology companies and Government, that processing denatures DNA. However, a study (October 2000) by the Advisory Committee on Animal Feeding Stuffs revealed that "DNA fragments large enough to contain potentially functioning genes" survived the processing of GM food for animal feed." This increases the concerns over horizontal gene transfer.
· Nutritional differences: Significant nutritional differences can result from the modification process, presumably due to the random, uncontrolled effects. These are not being properly assessed. For example, despite claims that Chardon LL had no such differences, a peer review of the company data revealed significant differences for fat, protein and fibre.
· Contamination of surrounding areas: Any risks from the growing of GM crops will apply to a large area around the crop. A review of the scientific literature by the National Pollen Research Unit concluded that, to protect biodiversity and non GM food from contamination by GM pollen, separation distances of several kilometres are needed. But despite the evidence, the government is still using industry backed distances, which are a fraction of those recommended.
How much do scientists really know about the risks from GMOs?
Though GMOs have been marketed for several years, scientific knowledge of the
processes involved are actually at a very early stage. In particular, very
little is known about the side effects of the genes' random location, how gene
function is controlled, and horizontal gene transfer. Key information and
experimental data is lacking in all of these areas. Moreover, new issues are
emerging the whole time, bringing new safety implications…
3. Tests for the Effects on Health
(i) Safety trials of GM foods are not required
With so much uncertainty, one would expect that the routine testing of GMOs for
health effects would be a legal requirement, before they can be sold or trialled
in the open countryside. This is the case for new pharmaceutical drugs ? they
undergo lengthy trials for all side effects to be discovered. However, contrary
to the impression given by the claims that all GMOs have been "rigorously
tested", the testing only amounts to establishing whether a GM crop is
similar in compositional terms to the non GM plant, through tests on the
levels of known compounds and toxins. This approach to risk assessment is called
the 'principle' of "substantial equivalence". But, as explained, all
the main concerns are not about known compounds but about unpredictable
effects resulting from the process. The reliance on this so called
'principle' is being condemned by many observers.
(ii) Shortage of independent and peer reviewed research
There is a shortage of experimental information on the subject. There have been
few peer reviewed and published studies and, moreover, very few independent
studies (three or four); most have been done by the companies. In other words,
for something as fundamental as the safety of a new technology to which everyone
is exposed, there is almost no credible information on which official decisions
can be based. Dr Pusztai's work on rats and GM potatoes, which found negative
effects, was the only Government sponsored work ever carried out on the
health effects of GMOs. Despite the attempts to discredit him, his paper
had been peer reviewed 6 times prior to publication (i.e. it was
probably the most reliable research on the subject).
(iii) Studies on the health effects
Interestingly, while the independent studies have all found problems, most of
the published company studies concluded there were no significant effects. But,
in some cases when other researchers have looked at these more closely, the data
actually contained negative effects. Overall, at least four studies have found
negative effects:
· Flavr Savr tomato: resulted in lesions, "gastritis", in the
rats. On a scale of 1-4, it was 2-3, but was described by the company as
"mild" and marketed as safe.
· GM potatoes: Dr Arpad Pusztai's experiments at the Rowett Institute found
gut lesions in the rats, suggesting damage to the gut immune system.
· GM forage maize (Chardon LL): twice as many chickens fed the maize died as
those fed non-GM maize. Yet, the Government approved the maize for use.
· BST: milk enhancing hormone, the first GM product used in agriculture.
Studies showed ill effects in cows and rats, but widely injected into cows in
the US.
From the above, the claimed safety of GMOs is contrary to the available evidence and based on very many assumptions. For example, GM foods have been approved on the assumption that all the health issues have been identified, that horizontal gene transfer will not create problems, that genes have only one function, that all side effects have been excluded etc.
4. Evidence of Effects in the General Population
Though it is claimed by the biotechnology companies that there have been no ill
effects of several years of GMO consumption in the US, there have actually been no
epidemiological studies to support this statement. Instead, the following
developments indicate negative effects may be occurring:
· UK: a 50% rise in soya allergies is reported since imports of GM
soya started
· Ireland: doctors report a rise in soya allergies in children since the
start of GM soya imports.
· US: people in the US reported allergic reactions to Adventis's Starlink corn,
after it mistakenly entered the American food chain. 12 of the cases are being
studied by the FDA to see if a link to the corn can be proven.
· US: coinciding with the introduction of GMOs in food in the US, food
derived illnesses are believed to have doubled over the last
seven years.
5. Conclusion
The genetic engineering process introduces numerous random hazards, and the
limited level of scientific understanding means that risk assessment and control
measures cannot be reliably designed. Therefore, at this stage of the
technology's development, the use of GM crops will lead to unpredictable and
possibly very serious impacts on health and the environment. Considering the
evidence, it is clear that decisions on the safety of GMOs and the necessary
containment measures are not being made on basis of science, but on assumptions
and industry opinion.
The way in which genetic engineering is being introduced into food production is completely unnecessary and unsound. We believe all research on GMOs should take place in contained conditions. There are many good solutions to the problems of agriculture which involve far less risk and uncertainty, and offer clear and substantial benefits. Investment should be preferentially directed at these solutions.
GM, 5.4.2001, GMOs005
Soil Association
Bristol House, 40-56 Victoria Street, Bristol BS1 6BY
T: 0117 929 0661 F: 0117 925 2504 E: info@soilassociation.org
Except for the underlining of the words in section (iii) as follows: Flav Savr tomato, GM potatoes, GM forage maize; BST, all the underlining is mine. Helen Ellery 27.5.01
File courtesy of Norfolk Genetic Information Network (ngin), http://www.ngin.org.uk thanks to Helen Ellery (see reply to adde) for forwarding this. NB. Except for the underlining of the words in section (iii) as follows: Flav Savr tomato, GM potatoes, GM forage maize; BST, all the underlining is mine. Helen Ellery 27.5.01
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