4.5—GM plants contain minute amounts of harmless new proteins
Very tiny amounts of transgene proteins are present in current genetically modified crops, and safety tests on them provide a large margin of safety.
Analysis of Peer-Reviewed Research:
In this section, Jeffrey Smith claims that the regulators of genetically modified crops ignore environmental influences on crop composition. This is implausible, as a major concept used for establishing GM food safety is comparison of a GM crop’s composition with the range of compositions found among conventional comparator crop varieties. Natural biological variability is a familiar topic to all biologists working on this issue and there are numerous scientific papers showing that conventional crop variety composition varies from season to season, from location to location, and from variety to variety. The International Life Sciences Institute provides databases of crop composition for exactly this reason (see www.cropcomposition.org). Thus the safety regulators would be fully aware of the need for margins of safety needed to ensure that variation in composition is irrelevant as a safety concern.
1. The Bt gene product in insect protected GM crops is always present at low level. Jeffrey Smith speculates that the concentration of this protein may be variable in plants growing in different locations, but he does not provide any evidence that the anything but a low level of transgenic protein is present in the crop. During the development of transgenic crops plants are commonly grown over several seasons at several sites and the amount of transgenic protein is evaluated in various tissues (leaf, pollen, stems, grain, roots) (Munkvold and others 1997, Munkvold and Hellmich 1999). These studies have shown that levels do indeed vary, but they are never very high. This is actually sometimes disappointing to researchers who are trying to achieve high levels of expression to ensure that the new protein will be present in sufficient quantity. To the biotechnologist under-expression is often a bigger challenge then over-expression (Agbios 2009, Betz and others 2000).
2. Large quantities of the transgenic protein have been fed to animals without having any effects. Safety testing on transgenic proteins provides a large margin of safety because only very low levels are present in a transgenic crop, and there is no evidence that the proteins are toxic to humans at any level. The safety margins are tens of thousands- to hundreds of thousand fold, making it virtually impossible for the plant to make unsafe levels. The proteins are fully digested in the human gut, converting them to harmless nutrients. It is also important to note that proteins are required nutrients that are almost always safe to eat (Betz and others 2000, Agbios website 2009, Delany and others 2008, EFSA GMO Panel Working Group on Animal Feeding Trials 2008).
3. Transgenic crop composition is assessed at different sites in different continents and different seasons. Jeffrey Smith discusses the importance of assessing the variability of crop composition due to environmental influences. He does not mention scientific studies that have been carried out to understand the extent of this variation as part of safety assessment (Reynolds and others 2005 , Ridley and others 2002).
Agbios (2009) Agbios website welcome page. www.agbios.com/main.php. AGBIOS is dedicated to providing public policy, regulatory, and risk assessment expertise for products of biotechnology. “Our website offers access to a database of safety information on all genetically modified plant products that have received regulatory approval, information on the implementation of biosafety systems, including case studies for food and environmental safety assessments, and a searchable library of biosafety-related citations in key topic areas.”
Betz FS, Hammond BG, and Fuchs, RL. (2000). Safety and advantages of Bacillus thuringiensis-protected plants to control insect pests. Regulatory Toxicology and Pharmacology 32:156-177. A key review which summarises the uses of Bt proteins to control insect pests in agriculture. Importantly provides key data substantiating the ~million-fold safety margins for Bt proteins
Delaney B, Astwood JD, Cunny H, Conn RE, Herouet-Guicheney C, Macintosh S, Meyer LS, Privalle L, Gao Y, Mattsson J, Levine M; ILSI International Food Biotechnology Committee Task Force on Protein Safety(2008). Evaluation of protein safety in the context of agricultural biotechnology. Food and Chemical Toxicology 46 Suppl 2:S71-97. Epub 2008 Feb 2. Review. Expert commentary on the safety examination of particular proteins relevant to transgenic crops.
EFSA GMO Panel Working Group on Animal Feeding Trials (2008). Safety and nutritional assessment of GM plants and derived food and feed: the role of animal feeding trials. Food Chemistry and Toxicology 46 Suppl 1:S2-70. Epub 2008 Feb 13. Review. Comprehensive and authoritative review of the state of play with animal feeding trials carried out with genetically modified crops, including discussion of their strengths and weaknesses. Experts associated with the European Food Safety Authority provide a comprehensive listing of many animal feeding tests and in-depth technical analysis of their interpretation.
Munkvold GP, Hellmich RL and Showers WB (1997). Reduced Fusarium ear rot and symptomless infection in kernels of maize genetically engineered for European corn borer resistance. Phytopathology 87:1071-1077 www.apsnet.org/online/feature/BtCorn/0902-01R.pdf accessed Dec 26 2008.
Munkvold GP and Hellmich RL (1999). Comparison of fumonisin concentrations in kernels of transgenic Bt maize hybrids and nontransgenic hybrids. Plant Dis. 83:130-138. www.apsnet.org/online/feature/BtCorn/1130-02R.pdf accessed Dec 26 2008.
Reynolds TL and Nemeth MA, Glenn KC, Ridley WP, and Astwood JD (2005) Natural variability of metabolites in maize grain: differences due to genetic background. Journal of Agricultural and Food Chemistry.53 (26):10061-10067 • DOI: 10.1021/jf051635q. Provides data illustrating changes in composition of a conventional food source due to different varieties and locations.
Ridley WP Sidhu RS, Pyla PD, Nemeth MA, Breeze ML and Astwood JD (2002) Comparison of the nutritional profile of glyphosate-tolerant corn event NK603 with that of conventional corn (Zea mays L.) Journal of Agricultural and Food Chemistry. 50 (25):7235-7243 DOI: 10.1021/jf0205662. Provides data illustrating that the variability in composition of a genetically modified food component falls within the range seen among existing conventional crop varieties.
1. Environmental factors, natural and man-made substances, and genetic disposition of a particular plant can influence levels of transgene expression and cause unique health effects
2. These factors are not adequately accounted for in assessments
Genetic Roulette claims that variations may occur in the amount of transgene protein when plants are grown at different locations, and speculates that this variability may be hazardous.