Bagi teman-teman yang tertarik, berikut laporan mutakhir dari para ilmuwan tentang keraguan akan keamanan pangan hasil rekayasa genetika. Mudah-mudah bermanfaat Salam Hira > -----Original Message----- > From: Debbie Ortman <[EMAIL PROTECTED]> > To: Recipient list suppressed <Recipient list suppressed> > Date: Wednesday, May 24, 2000 3:22 AM > Subject: Please Read and Post - 10 distinguished scienctists - GE foods are > unsafe! Physicians and Scientists for Responsible Application of Science and > Technology (PSRAST) > > > The safety of GE foods > Reasons to expect hazards and the risk for their appearance > > It is our aim to make this important information comprehensible for the > layman. Therefore we have tried to keep the language as simple as possible. > If you have difficulties in following the text, we suggest you read "What > is genetic engineering?" [EL], and linked documents. > > Authors: > Dr Michael Antoniou M.D., Senior Lecturer in Molecular Genetics, GKT School > of Medicine, King's College, London, UK > Dr Joseph Cummins PhD, Professor Emeritus in Genetics, University of > Western Ontario London, Ontario, Canada > Dr Edwin E. Daniel Ph.D. FRSC, Professor Emeritus Health Science, Faculty > of Health Sciences, McMaster University, Hamilton, Ontario Canada > Dr Samuel S. Epstein M.D., D.Path., D.T.M&H, Professor of Environmental and > Occupational Medicine at the School of Public Health, University of > Illinois Medical Center Chicago, USA > Dr C. Vyvyan Howard MB. ChB. PhD. FRCPath. Senior Lecturer, > Toxico-Pathologist, University of Liverpool, UK > Dr Bob Orskov DSc, OBE, FRSE, Honorary professor in Animal Nutrition of > Aberdeen University, Macauley Land Use research Institute, Aberdeen, UK > Dr Arpad Pusztai FRSE, Biochemistry&physiology. Retired, formerly at Rowett > Institute, Aberdeen, UK. > Dr N. Raghuram Ph.D., (Plant Molecular Biology) Lecturer, Department of > Life Sciences, University of Mumbai, (formerly Bombay), India. > Dr Gilles-Eric Seralini PhD, Hab.Dir.Rech., Professor in Molecular biology, > University of Caen, France > Dr Suzanne Wuerthele Ph.D., Toxicologist and risk assessor, Denver, > Colorado, ISA > Editor: Dr Jaan Suurkula, M.D. Chairman of PSRAST > > Contents > General conclusion. > Reasons why GE may cause the appearance of unexpected substances > Is it possible today to estimate the risk for appearance of harmful > substances due to genetic engineering? > Problems with food safety testing > > 1. General conclusion > Based on both scientific theory and experimental data, it can be concluded > beyond any doubt that genetic engineering of plants and animals may > potentially cause them to unexpectedly contain substances harmful to people > who eat them. Scientists cannot however estimate the probability that > harmful substances will be created in any specific case, because not enough > is known about the new field of genetic engineering. > Some of the harmful substances which are known to be possible in > genetically engineered foods could cause allergies or toxic reactions. But, > because the knowledge of DNA is incomplete, genetic engineering of food > plants and animals may produce other problems which scientists have not yet > anticipated. > > So GE foods are inherently unsafe and we neither have enough knowledge to > estimate the risk for harmful effects nor fully reliable testing methods. > > > 2. Reasons why GE may cause the appearance of unexpected substances > Molecular biologists have shown in the laboratory that the insertion of a > gene may induce unexpected metabolic changes that in the worst case may > result in harmful substances for the following reasons: > > With presently used techniques, it is impossible to guide the insertion of > a gene. Therefore, it will occur haphazardly in the midst of the ordered > code sequence of DNA. This will perturb the normal close control of DNA > over metabolic processes resulting in unpredictable effects on the > metabolism. This is especially so as, to be successful, the inserted gene > has to be inserted in a region of DNA that is active (most of DNA is > inactive, and genes inserted there will not have any effect). > > > "The socalled promoter that is always included in gene insertion packages, > may cause metabolic disturbances (the most commonly used promoter comes > from the Cauliflower Mosaic Virus "CaMV"). The promoter is added because it > is an absolute requirement to ensure the inserted gene is "read"; i.e. > copied into RNA and translated into the protein for which it codes. In > addition, other regulatory sequences called enhancers are often included as > they strongly stimulate gene expression. However, the socalled enhancers > also stimulate the activity of surrounding native genes with potentially > deleterious consequences. The metabolism of the cell may become disturbed > in unpredictable ways. The enhancers may also activate genes that should > normally bee inactive. For example a toxic protein that normally is only > expressed in the leaves of a food plant, may become active in the fruit or > seeds used. Moreover, normally, the activity of genes is the result of a > refined regulation of their expression, so no gene is active longer than > needed. The artificially inserted strongly stimulating promoter-enhancer > complex without any coupling to inherent regulatory mechanisms eliminates > this delicate demand/supply regulation. This may have unpredictable effects > on cellular functioning." > > Genetic engineering means in most cases the insertion of a gene coding for > a protein foreign to the species. There is no way of knowing what the > presence of a foreign protein will have on the metabolism and functioning > of an organism. It may have unexpected effects in addition to its desired > effect including the possibility that it may cause the generation of a > harmful substance. > > The effect of a gene is context dependent. In a foreign environment, it may > have unpredictable effects. These effects may be difficult to detect but > might in the worst case generate harmful substances. See "The new > understanding of genes". > > Most of the foreign proteins that are used in genetic engineering have > never existed in food. There is no way of knowing beforehand, without > extensive food safety assessment, if it is safe to eat food containing such > proteins. > > Regulatory genes may inadverently be included in the inserted gene, causing > unpredictable complications (however, with the kinds of genes presently > used, this risk is considered unlikely). The knowledge of regulatory genes > is incomplete so there is a risk that an inserted DNA sequence may possess > unanticipated regulatory activities. These genes regulate the activity of > other genes. This might disrupt any of the cellular processes in which DNA > or RNA participate which might result in many kinds of unexpected effects > including the production of harmful substances, (for more details, see The > underlying mechanism involved in the "reading" of regulatory information... > [AL]; (part of an article by John Fagan).) > If so called fusion proteins are generated through GE, they may cause > unexpected allergies that may be more allergenic than proteins produced by > the original DNA sequences. Fusion proteins are created by linking pieces > of DNA sequences from two or more sources. The regions where two proteins > are joined can assume conformations very different from those of either of > the original proteins. Furthermore, the likelihood of generating > allergenicity in fusion proteins is increased by the fact that the > junctions at which two proteins are fused often assume configurations that > are not common in natural proteins, and are, therefore, more likely to be > allergenic. There are also other reasons why genetic engineering might > caused increased problems with allergens, see Allergens generated in > recombinant foods [AL]; by John Fagan. > > > A special class of hazards might be unexpected effects of known substances. > Obvious candidates are GMOs modified to produce pesticides, substances > designed to be toxic. An example of this is the demonstration of long term > toxicity of a strain of GMO potato by Arpad Pusztai (Lancet 1999 Oct > 16;354(9187):1353-4). > Conclusion > There are several known ways in which the artificial insertion of a gene > may cause unexpected complications of a kind that never occurs in > conventional breeding. Some unexpected effects have been experimentally > verified, see Examples of unexpected effects of genetic engineering. In > addition, because the knowledge about DNA is very incomplete, there may be > effects that cannot be even imagined presently, see "Incomplete knowledge > about DNA" > > It took almost 50 years after the introduction of nuclear technology and > synthetic pesticides to appreciate the health and environmental hazards > they present. Because recombinant DNA technology (genetic engineering) is > even more complex, and because we have almost no experience with it, it is > reasonable to expect future surprises. > > The U.S. FDA and the European Union have been denying any hazards with GE > foods. It is satisfying to find that evidence have been unearthed > indicating that this has been the result of suppression of truth, see > footnote. > > > 3. Is it possible today to estimate the risk for appearance of harmful > substances due to genetic engineering? > Risk is the probability that some adverse effect (hazard) will occur in the > future. Of course, no one can predict the future with perfect certainty. > The degree of accuracy of a risk assessment is dependent on how much > relevant information is available, the quality of that information and how > well that information is interpreted. Thus, some risk assessments are more > reliable than others. For example, because insurance companies have many > years worth of information about automobile accidents, they can predict > rather well the characteristics of drivers (using data on age, sex, type of > car, and accident history) is most likely to be involved in an accident. On > the other hand, because the physics of only a few major earthquakes have > been monitored with sophisticated seismic equipment, and because there are > debates about what physical signals are important indicators, it is not yet > possible to predict the likelihood of a major occurrence. > Specifically, it is not possible to assess the risk of harm from eating GE > food with a high degree of accuracy because: > > �Genetic control of cell function is not well understood (see footnote > �Incomplete knowledge of DNA). Not even the DNA sequence of presently > marketed genetically engineered plants is fully known. > In order to understand what can go wrong with a system and to evaluate its > potential to go wrong, it is first necessary to understand how the system > works. A cardiologist must understand anatomy, physiology, biochemistry and > pharmacology to diagnose heart disease, predict outcome and prescribe > appropriate remedies. Since the genetic control of cell function is an > extraordinarily complex system which is only poorly understood, our > comprehension of all that can go wrong when foreign genes are added to > foods, our ability to predict the outcome of eating such foods, and our > ability to design safe GE foods is highly limited. Furthermore, as anyone > who uses a computer knows, the opportunity for malfunction is increased as > systems become more complex and as the manipulation of complex systems > becomes more random and uncontrolled. > �Laboratory experiments with GE have been very limited. For some (but not > all) GE foods, some short-term studies have been conducted on experimental > animals. But there are almost no long-term toxicological, neurological, > metabolic, endocrinological, developmental or reproductive studies of these > foods. Such studies are necessary to evaluate the effects of substances > which are slow-acting, have cumulative or reproductive effects. For details > see �"The approval of Roundup Ready GE-Soy - based on incomplete evidence" > and for a suggested procedure, see �"Testing the safety of genetically > engineered foods" by professor John Fagan. > > �Human experience with GE foods has been very limited. GE foods have been > on the market for only about five years, so there obviously has been no > experience with long-term exposure to these novel foods. Few controlled > short-term human studies have been conducted on these new foods. Moreover, > since GE foods have not been labeled, there has been no way for scientists > to compare the health of people who have and have not been eating them. > In contrast, humans have had thousands of years of experience with > naturally occurring foods, and the conditions under which they pose hazards > (e.g., eating solanine in green potatoes) are well-known. > > The problems of risk assessment per se have been further aggravated by the > way regulatory agencies have been handling the GE food issue, see footnote: > Unsatisfactory handling by regulatory agencies. > Conclusion > There is no scientific knowledge at all that makes it possible to estimate > how likely it is for harmful substances to be generated in GE foods. But we > can definitely say today that there is no scientific basis for maintaining > that harmful substances may not appear or are very unlikely. > > > 4. Problems with food safety testing > Safety testing of GE foods is problematic because genetic engineering may > give rise to unexpected and unpredictable substances. It is illuminative to > compare with a closely related field, the testing of medical drugs, > especially as there is an extensive experience of the reliability of such > testing. > �On the basis of knowledge about the chemical properties of a medical drug, > it is possible to predict, to a quite large extent, what kind of harmful > effects might occur. In the case of GE foods, there is no clue to decide if > an unexpected substance may be toxic, allergenic, carcinogenic, mutagenic > or otherwise harmful. > �In medical drug testing, it is possible to expose test objects to several > times higher doses than used clinically. This helps to get an idea of the > harmfulness of a drug. For foods, such a procedure is impossible because it > would give rise to nutritional imbalances. > For these reasons, it is considerably easier to detect harmful effects of a > medical drug than of a GE food. Still about 3 percent of drugs released on > to the market have been withdrawn because of unexpected harmful effects > that were not revealed until the drug had been used at a large scale. And > about 10 percent have had so serious side effects that their use has been > considerably restricted. Yet the drug companies have been using the best > available methods in the world. Laboratory animal and human testing has > been used as well as long term clinical studies. They have been applying > the tests very rigorously and carefully. This is because the development of > a new drug is very expensive, so a forced withdrawal from the market means > a loss of billions of dollars. > The greatest problem in toxicological testing is to reveal long term > harmful effects. Against the experiential backgound from medical drug > testing, it can be confidently predicted that even most rigorous safety > testing of GE foods is likely to fail to detect long term harmful effects > to a considerable extent. > The only way of minimizing the risk of not detecting unexpected harmful > effects of harmful substances is to use long-term testing. As animals are > not fully reliable predictors of food safety for humans, it is necessary to > use Physicians and Scientists for Responsible Application of > Science and Technology (PSRAST)long term > humhttp://www.psrast.org/defknfood.htman studies. > Strategies for long term testing of GE foods have been suggested by > professor Arpad Pusztai, see "The need for rigorous biological risk > assessment" and professor John Fagan, see Testing the safety of genetically > engineered foods. > As experimental long term testing is not sufficient to ensure safety, Fagan > has suggested a monitored premarketing test on a population of about > 2.000.000-3.000.000 people during 2-3 years with close surveillance of its > health status. Even with that test included, he concludes that there will > remain a "residual risk" for unexpected long term damage. > These testing schemes are fundamentally different from the superficial > testing that has been presently been accepted for approval of GE foods, see > "Substantial equivalence versus scientific food safety assessment" > > Footnotes > Incomplete knowledge about DNA > Suppression of truth turning untenable > Unsatisfactory handling by regulatory agencies > > Published in May 1999. The present version is the result of an ongoing and > not yet completed revision through the contribution from new co-authors. > Latest update: May 12, 2000. > > All the authors of this document have, along with several other scientists, > signed an Open Letter demanding that GE foods that have not been tested > properly should be withdrawn from the market (in practice this means all GE > foods). > > To: General conclusion of this article > > Back to the page: "Is there sufficient scientific knowledge to ensure safe > commercial exploitation of genetically engineered foods?" > > "Genetically Engineered Food - Safety Problems" > Published by PSRAST > Starting points Website search Site Map Home page Introductory articles > Newspage > > Health hazards Environmental hazards Global issues Safety issues Open Letter > > FAQ About us Membership Contact us How to sponsor us > > http://www.psrast.org/defknfood.htm > > Physicians and Scientists for Responsible Application of > Science and Technology (PSRAST) > > Jaan Suurkula <[EMAIL PROTECTED]> ,[EMAIL PROTECTED] > > -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Archive: http://www.mail-archive.com/[email protected]/
