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With recent attention in the popular press, more people are aware of the presence of genetically engineered foods in our diets and are asking the question, "Are these foods safe?" Because long-term studies and tests have not been done, it is essential that we educate ourselves regarding the risks from genetically engineered foods.
Food Safety Risks of Genetically Engineered Crops
Many engineered foods contain genetic material that has never before been part of the human diet, and virtually all such foods involve genetic recombination that would be impossible through conventional breeding methods. The process of genetic engineering inserts foreign genes, as well as promoter and marker genes, into random locations in the food crops' genome. This creates additional unknown risks. Some of the potential health threats of transgenics include:
Allergies: There is clear evidence that allergens can transfer unexpectedly via genetic engineering. (1) In one example, a Brazil nut gene was inserted into a soybean to improve the protein profile of the bean. Scientists believed that the inserted protein would be harmless to people with nut allergies. Yet allergy tests proved otherwise. In this case, the genetic transfer was from a source known to cause allergies; most engineered foods involve proteins that have never been thoroughly tested for allergenicity. The Food and Drug Administration only requires labeling of genetically altered food if a known allergen is involved, a policy that Dr. Marion Nestle, chair of the Nutrition and Food Studies Department at New York University, has criticized as appearing "to favor industry over consumer protection." (2)
Antibiotic Resistance: Many transgenic plants contain antibiotic resistance "marker" genes, which may contribute to the spread of antibiotic resistance among disease-causing bacteria. Transfer of genetic material from plants to bacteria and fungi has been demonstrated, and a recent study concluded that the widespread cultivation of transgenic plants containing antibiotic resistance genes would favor the spread of resistance. (3,4). Proponents of the technology claim that these genes only confer resistance to antibiotics that are no longer widely used. Yet Novartis markets transgenic corn containing a gene for resistance to ampicillian, which could confer resistance to one of today's most widely used classes of antibiotics. (5) Moreover; at least one marker gene in use has been found to confer cross-resistance to other commonly used antibiotics, and relatively common mutations in marker genes resistant to antiquated antibiotics can also lead to cross-resistance to currently useful antibiotics, making a marker that is presumed safe into a more risky one. (6,7).
The unpredictability of genetic engineering means that unintended and potentially toxic effects are quite possible.
Toxic Effects: The unpredictability of genetic engineering means that unintended and potentially toxic effects are quite possible. A dietary supplement, tryptophan, was produced with the aid of a genetically altered bacteria in the late 1980's. In 1989, this engineered tryptophan was identified as the cause of 37 deaths and thousands of cases of serious illness. The tryptophan contained a toxic substance that appears to have been the by-product of the genetically engineered bacteria. (8). Engineered strains of yeast, tobacco plants, and some recombinant bovine and porcine growth hormone contained highly toxic substances unexpected from the engineering process. (9). Foreign genes introduced into crop plants usually require a "promoter" gene to assure that the inserted gene remains active in its new host. Scientists warn that the action of these promoter genes may result in the unintended production of toxic substances in genetically engineered plants and animals. (10).
Herbicide Use: The major application of genetic engineering being pursued today is crops altered to tolerate toxic herbicides-making up over 70% of the transgenic plant acreage in the US. (11). Crops have been engineered to withstand glyphosate (trade-named Roundup), bromoxynil, and atrazine, among other farm poisons. The incentive for farmers to use chemicals more freely poses health threats to farm workers and consumers. Glyphosate is the third most commonly cited cause of pesticide poisoning among California agricultural workers (12). While developing glyphosate-tolerant "Roundup Ready" soybeans, Monsanto successfully lobbied to raise the allowable residue level of glyphosate on soybeans by more than a factor of three. (13) Bromoxynil causes cancer and birth defects in laboratory animals and is considered by EPA to be a developmental toxin and possible human carcinogen. (14) Atrazine has contaminated groundwater water in 25 states, and is banned for sale in most European countries. (15)
...any system which promises control of complex ecological processes by targeting one or just a few variables is doomed to fail...
New Viruses: By incorporating foreign virus genes, genetic engineers confer virus resistance to a plant. Yet lab experiments have shown that new and potentially more deadly viral strains can be created when such engineered varieties are infected with a virus. (16) While this is largely a concern for the protection of crops from disease, some scientists warn that ingested viral DNA may be able to resist breakdown in the gut and recombine with human viruses, causing new diseases. (17)
Engineered Plants: Magic Bullets from Land to Mouth
These risks of genetically altered foods are indeed worrisome. Still, industry believes that science can overcome these obstacles and herald an era of foods "improved" through biotechnology. While the current crop made up primarily of herbicide tolerant plants and virus or insect resistant ones offer no benefit to consumers, industry promises that "second generation" engineered varieties will focus on nutritionally improved and pharmaceutically valuable foods. "Functional foods" or "nutraceuticals" will target heart disease, cancer, high blood pressure and other illnesses, making "healthy eating" possible without any change in dietary habits. Steak and eggs, for example, become a "heart healthy" meal when the eggs are engineered with heart disease fighting nutrients.
This ill-conceived notion of nutrition mirrors the genetic engineers' distorted understanding of agriculture. Ecological critiques of agricultural genetic engineering assert that biotechnology merely substitutes a biological-control model for the current model of chemical controls. (18) But any system which promises control of complex ecological processes by targeting one or just a few variables is doomed to fail, and likely in the long run to lead to unintended problems more severe than the original ones. The history of chemical pesticides illustrates the dubious "success" of agrochemical corporations' strategy of planned obsolescence: each new toxic pest control promotes natural resistance, forcing farmers to return to the agrochemical corporation to buy new chemicals. This "pesticide treadmill" has bound farmers to agrochemical companies, and amassed enormous profits for those companies for 50 years. Meanwhile, the health and environmental costs of pesticides are estimated at $2-4 billion annually, and include an estimated 20,000 cases of pesticide-caused cancers each year. (19)
The case of insect-resistant "Bt crops" shows how biotechnology follows the "treadmill" model. Bacillus thuringiensis (Bt) is a naturally occurring bacterial insecticide, the only such agent permitted for use in organic farming. By altering crops to produce Bt toxin, genetic engineers promise insect control with fewer toxic chemicals. Organic farmers use Bt sparingly, only in emergency situations, but with widespread cultivation of Bt crops, entomologists warn that insects will rapidly develop resistance to Bt. (20). When other farmers are sold the next chemical or genetically engineered control, organic farmers will be left defenseless against these Bt resistant "superbugs." A technology that threatens the worldwide viability of organic farming can hardly be called environmentally friendly. (21)
Simply moving from chemical to biological pollution is obviously no solution.
Jane Rissler of the Union of Concerned Scientists has characterized Bt crops as "just another in a long line of short-lived, magic-bullet solutions that have dominated US agriculture for the last 50 years." (23) Nutritional scientists have been similarly shortsighted in their approach to diet and health. While modern processed foods have sapped the nutritional qualities of whole, unadulterated foods, nutritionists have focused on "fortification," "enrichment," and other ways to manage diets replete with empty calories. In the past decade there has been an explosion in the development and marketing of "functional foods" that target specific health problems. The corporations driving the genetic engineering of our food-the same companies that market agrochemicals-are seeking to capitalize on this trend. Biotech products in development include tomatoes engineered for higher cancer-fighting beta-carotene levels and cholesterol-lowering corn oil. (23)
Sustainable agriculture requires long-term solutions that are truly environmentally beneficial. Simply moving from chemical to biological pollution is obviously no solution.
The American diet today includes 33% more dairy products, 50% more beef and 280% more poultry than our diet did 100 years ago. (24) Meat consumption is up in the US and the developing world, yet meat production is exponentially more environmentally taxing than food crop production. It is no coincidence that corn and soybeans, two major animal feed crops, are among the leading products of genetic engineering. Monsanto is pushing hard to bring biotech soybeans to Brazil, where large plantations primarily grow beans for feed to cattle for beef exports, while five million people there face starvation annually. (25) Meanwhile, the evidence that the healthiest diets are plant-centered is incontrovertible. According to Marion Nestle, "There is no question that largely vegetarian diets are as healthy as you can get. The evidence is so strong and overwhelming and produced over such a long period of time that it's no longer debatable."(26)
Those concerned with better health through diet should not fall prey to the false promises of biotechnology. "Magic bullet" approaches to eating will fare no better than such strategies have in farming, and will likely lead to unforeseen health problems in much the same way that unintended consequences have plagued chemical-based systems, and will plague biotech crops
Meat consumption is up in the US and the developing world, yet meat production is exponentially more environmentally taxing than food crop production.
1. Nordlee, J.A., Taylor, S.L.,Townsend, J.A., Thomas, L.A. & Bush, R.K. (1996). Identification of a brazil-nut allergen in transgenic soybeans. The New England Journal of Medicine, 334(11): 688-92.
2. Nestle, M. (1996). Allergies to transgenic foods: Questions of policy. The New England Journal of Medicine, 334(11): 726-727.
3. Schluter, et al, (1996). Hoffman, et al (1994). Cited in M. Ho and R. Steinbrecher (1998). Fatal Flaws in Food Safety Assessment: Critique of the Joint FAO/WHO Biotechnology & Food Safety Report, Third World Network, 40.
4. Courvalin, P. (1998). Transgenic Plants and Antibiotics. Translated by Elisabeth Abergel for the Edmonds Institute from La Recherche (May, 1998), 309, 36-40.
6. Ho, M.(1998). Genetic Engineering: Dream or Nightmare. Gateway Books: Bath, UK, 138.
7. Courvalin, (1998).
8. Hansen, M. (1998). Why We Need Labeling of Genetically Engineered Food, Consumers International report.
9. Antoniou, M. (1998). Are Genetically Engineered Foods Without DNA Safe? (correspondence).
10. Ho, M. & Steinbrecher, R. (1998). Joe Cummins, (1998). A Viral Promoter Used in the Majority of Genetically Engineered Crop (correspondence)
11. Brookes, M. Coghlan, A. (October 31, 1998). "Live and Let Live," New Scientist.
12. Cox, C. (Fall, 1998). Herbicide Factsheet: Glyphosate. In Journal of Pesticide Reform, 18(3), 9.
13. Lappe, M. & Bailey, B. (1998). Against the Grain, Common Courage Press, 75-76.
14. Rissler, J. & Mellon, M. (1996). The Ecological Risks of Engineered Crops, MIT Press, 16.
15. Greer, J. & Bruno, K. (1996). Greenwash: The Reality behind Corporate Environmentalism, Third World Network, 154.
16. Cummins, J. The Danger of Virus-Resistant Crops. (correspondence)
17. Ho, M. (1998). 140-142.
18. See Rissler, J. (January 1991). Biotechnology and Pest Control: Quick Fix vs. Sustainable Control. Global Pesticide Campaigner. Altieri, M. (Spring/Summer, 1998). The Environmental Risks of Transgenic Crops: An Agroecological Assessment, Pesticides and You.
19. Orr, D. (1994). Earth In Mind, 173.
20. For detailed look at Bt crops, see Now or Never, Mellon, M. & Rissler, J. (Eds.) (1998) Union of Concerned Scientists.
21. This and other risks of Bt crops prompted Greenpeace and over 30 organic farming organizations in the US to petition the EPA, calling on the agency to suspend the registration of Bt crops.
22. Rissler, J. (March, 1997). Bt Cotton-Another Magic Bullet? Global Pesticide Campaigner, 7(1), Pesticide Action Network North America, San Francisco, CA.
23. Correspondence with Steve Emmott.
24. Worldwatch Institute, Vital Signs (1996). New York: Norton, on earthsave.org web site.
25. Mack, D. (October 31, 1998). "Food for All," New Scientist.
26. Liebman, B. (Oct., 1996). "Plants for Supper: 10 Reasons to Eat More Like a Vegetarian," Nutrition Action Healthletter, 10-12. On the earthsave.org web site at at http://www.earthsave.org/intl/news/research/199703.htm.