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| Influence of genetically modified plant foods |
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| Written by Administrator |
| Friday, 10 July 2009 05:53 |
Could genetically modified plant foods have health effects? The scientific evidence concerning the environmental and health impacts of genetic engineeringis still emerging. This chapter briefly summarizes the current state of scientific knowledge on the potential health and environmental risks (Box 17) associated with genetic engineering in food and agriculture, followed by a discussion of the role of international standard-setting bodies in harmonizing risk analysis procedures for these products (Box 18). The scientific evidence presented in this chapter relies largely on a recent report from the International Council for Science (ICSU, 2003 - referred to hereafter as ICSU). The ICSU report draws on 50 independent scientific assessments carried out by authoritative groups in different parts of the world, including the FAO/WHO Codex Alimentarius Commission, the European Commission, the OECD and the national science academies of many countries such as Australia, Brazil, China, France, India, the United Kingdom and the United States. In addition, this chapter draws on recent scientific evaluations from the Nuffield Council on Bioethics (2003 - referred to hereafter as Nuffield Council), the United Kingdom GM Science Review Panel (2003 - referred to hereafter as GM Science Review Panel) and the Royal Society (2003 - referred to hereafter as Royal Society) that were not available when the ICSU report was prepared. There is a substantial degree of consensus within the scientific community on many of the major safety questions concerning transgenic products, but scientists disagree on some issues, and gaps in knowledge remain. Food Safety implicationsCurrently available transgenic crops and foods derived from them have been judged safe to eat and the methods used to test their safety have been deemed appropriate. These conclusions represent the consensus of the scientific evidence surveyed by the ICSU (2003) and they are consistent with the views of the World Health Organization (WHO, 2002). These foods have been assessed for increased risks to human health by several national regulatory authorities (inter alia, Argentina, Brazil, Canada, China, the United Kingdom and the United States) using their national food safety procedures (ICSU). To date no verifiable untoward toxic or nutritionally deleterious effects resulting from the consumption of foods derived from genetically modified crops have been discovered anywhere in the world (GM Science Review Panel). Many millions of people have consumed foods derived from GM plants - mainly maize, soybean and oilseed rape - without any observed adverse effects (ICSU).The lack of evidence of negative effects, however, does not mean that new transgenic foods are without risk (ICSU, GM Science Review Panel). Scientists acknowledge that not enough is known about the long-term effects of transgenic (and most traditional) foods. It will be difficult to detect long-term effects because of many confounding factors such as the underlying genetic variability in foods and problems in assessing the impacts of whole foods. Furthermore, newer, more complex genetically transformed foods may be more difficult to assess and may increase the possibility of unintended effects. New profiling or “fingerprinting” tools may be useful in testing whole foods for unintended changes in composition (ICSU). The main food safety concerns associated with transgenic products and foods derived from them relate to the possibility of increased allergens, toxins or other harmful compounds; horizontal gene transfer particularly of antibiotic-resistant genes; and other unintended effects (FAO/WHO, 2000). Many of these concerns also apply to crop varieties developed using conventional breeding methods and grown under traditional farming practices (ICSU). In addition to these concerns, there are direct and indirect health benefits associated with transgenic foods that should be more fully evaluated. Allergens and toxinsGene technology - like traditional breeding - may increase or decrease levels of naturally occurring proteins, toxins or other harmful compounds in foods. Traditionally developed foods are not generally tested for these substances even though they often occur naturally and can be affected by traditional breeding. The use of genes from known allergenic sources in transformation experiments is discouraged and if a transformed product is found to pose an increased risk of allergenicity it should be discontinued. The GM foods currently on the market have been tested for increased levels of known and allergens toxins and none has been found (ICSU). Scientists agree that these standard tests should be continuously evaluated and improved and that caution should be exercised when assessing all new foods, including those derived from transgenic crops (ICSU, GM Science Review Panel).Antibiotic resistanceHorizontal gene transfer and antibiotic resistance is a food safety concern because many first-generation GM crops were created using antibiotic-resistant marker genes. If these genes could be transferred from a food product into the cells of the body or to bacteria in the gastrointestinal tract this could lead to the development of antibiotic-resistant strains of bacteria, with adverse health consequences. Although scientists believe the probability of transfer is extremely low (GM Science Review Panel), the use of antibiotic-resistant genes has been discouraged by an FAO and WHO expert panel (2000) and other bodies. Researchers have developed methods to eliminate antibiotic-resistant markers from genetically engineered plants |
| Last Updated on Friday, 10 July 2009 08:22 |