[PART ONE OF TWO - References and footnotes at end of two] ---------------------------------------- Genetically Engineered Foods: Potential Impact on Health
By Shirley Watson DC, CCN, DACBN, AME, & Barbara Keeler (Reprinted by permission from the ACA Council on Nutrition's Nutritional Perspectives, October 1999, Vol. 22, No. 4, pp. 23-32) If the present trend continues, chiropractors will face increasing challenges in diagnosing diet-related conditions and in prescribing appropriate meal plans. Without changes in food labeling laws, they will not know what their patients are ingesting. In 1996, genetically engineered (GE) foods were quietly introduced into the market place. They spread rapidly. Three varieties of soy, ten varieties of corn, papaya, yellow neck squash, canola, potatoes, tomatoes, dairy, and animal products are already on the tables of most consumers-with more than a hundred expected soon. According to most estimates, 60 to 70 percent of all processed foods contain genetically modified ingredients, including proteins previously absent from human diets. (1) Patients may look to their health care providers for advice about GE foods. Having seen ads by well-funded GE seed companies promising tastier, more nutrient-dense, allergen-free foods, and an end to world hunger, they might wonder why farmers in India torched Monsanto's cotton crops, and why citizens in Ireland, France, and California ravaged Monsanto's GE food crops and GE seeds. (2) Authoritative regulatory bodies present conflicting views as well. The United States Food and Drug Administration policy is that most genetically engineered foods are substantially equivalent to their unmodified counterparts and do not require labeling or special pre-market testing. By contrast, the Canadian equivalent to the FDA and the Codex Alimentarius Commission, the United Nations Food Safety Agency, and the UK Ministry of Agriculture questioned the safety of certain GE foods, especially dairy products from cows treated with bovine growth hormone. Medical boards, such as the British Medical Association, the European Union's Scientific Veterinary Committee, and the German equivalent to the American Medical Association have issued warnings or raised concerns. Beyond advising patients, chiropractors will need to decide whether or not they want to carry nutritional supplements containing GE foods. Should they decline, they need to know how to avoid them-a challenging task under current regulations, which do not require segregation or labeling of GE products. In the near future, demand by consumers should give incentives to this industry to supply alternatives. What is Genetic Engineering? Any dispassionate assessment of potential benefits and hazards of genetic engineering must begin with an understanding of the processes involved. "Genetically engineered" (GE), "transgenic," "genetically modified" (GM), and "transformed" are all terms that relate to a wide range of agricultural, industrial, and medical products in which genetic codes have been altered using recombinant DNA techniques. Genetic engineers intend to confer on the genetically engineered organism (GEO) new characteristics not found in the original, unmodified organism (UMO). Eighty percent of biotechnology research is directed at modification of food plants. The remaining biotechnology research is on non-food crops, such as cotton, ornamental plants, and pharmaceuticals. The GE Process Below is a summary of a typical GE process. Hazards can be introduced at any of the following steps. Some hazards could directly impact patients who ingest the food. Other hazards are indirect, operating through pollution of other food species, or through unintended effects on local and global ecosystems. 1. First, the new gene, or transgene, is isolated as a stretch of DNA, and linked or spliced to a suitable promoter. This part of the process can be performed with precision. A promoter is a DNA sequence that regulates the activation of a gene and determines where, when, and to what degree the transgene is expressed in the new GE organism. The intended function of the transgene is to code for production of a protein, which, in turn, will catalyze a biochemical reaction in the plant. 2. Next, the new spliced gene is inserted into the unmodified organism's own chromosomes, usually in cultured cells or seed embryos. Insertion of transgenes cannot be executed with precision, and has been likened to "heart surgery with a shovel." The two most common methods are Agroacterium and the "gene gun." a. Agrobacterium: Called "nature's genetic engineer," this infectious bacterium naturally transfers DNA to its plant host. The bacterium is modified to carry the engineered gene, then introduced into a host plant cell, where the new genes integrate into the host DNA of the plant cells. The technique has been criticized for the occasional transfer of DNA from the bacteria and introduction of live-engineered bacteria into the environment. b. The gene gun: Gold or tungsten micro-particles are coated with transgenes and fired into the targeted cells or tissues. One or more copies of the transgene integrate into chromosomes of some targeted cells. With either technique, the transgene(s) cannot be directed to a specific location on the host chromosomes. Incorporation into the host DNA is more or less at random. Only a small percentage of the treated cells are transgenes successfully incorporated into the DNA. For scientists to identify the cells to which transgenes are actually transferred, marker genes are usually linked under Step 1. Genes resistant to antibiotics or herbicides are the markers of choice. After insertion, genetic engineers add antibiotics or herbicides that kill all cells except those with the resistance marker, which is linked to the desired transgene. 3. The transformed cells grow into intact plants. Hazards and Problems The main sources of health and environmental hazards and problems fall into four categories. They can arise from 1) characteristics of the transgenes and new gene products introduced, or the organism from which they are derived; 2) unintended side effects inherent in the technology; 3) interactions between foreign genes and host genes; and 4) the unintended transfer of introduced genes to other organisms and species. (3) Social and economic hazards result from increasing corporate control of food production and distribution, which threatens the variety and distribution of the food supply. Of particular concern is this trend's potential impact on the poor in the developing world. Potential Hazards from Selected Transgenes and Gene Products Novel genes introduced into food seeds are often from bacteria, viruses, and other non-food species. They become blueprints for proteins never previously consumed by humans in the quantities produced in GE crops, where they are typically expressed at high levels. Scientists warn that the long-term impacts of these genes on human health are impossible to predict. Without segregation of GE products and post-market monitoring, manifested effects will be almost impossible to assess. Below are a few examples of novel genes and the hazards they can introduce. Toxin-Producers According to Food and Drug Administration document 57, Federal Register 22987, "Corn and potatoes engineered to produce toxins that kill insects are now classified by the EPA as pesticides, rather than vegetables." Most of the toxins produced by GE plants are bacillicus thuringiensis (Bt) toxins. They bind to sites in the digestive system of a target insect, inflicting damage that quickly proves fatal. Plants have also been engineered to produce snowdrop lectins, which have demonstrated toxicity to mammals and non-target insects. Herbicide-Resistant Genes Of all genetically altered crops last year, 71 percent carried genes for tolerance of a specific herbicide made by the company engineering the seeds-for example, Monsanto's Roundup Ready soybeans. They guarantee exposure to herbicides with a litany of adverse health effects. The risks of these GE crops will be examined later in this article. Antibiotic-Resistant Genes In Federal Register 22988, the U.S. FDA warns of "decreased effectiveness of antibiotics due to antibiotic-resistant genes incorporated into every genetically engineered organism, as markers to indicate that an organism has been successfully engineered. Scientists expect these genes and their enzyme products, which inactivate antibiotics, to be present in engineered foods." Indeed, the British Medical Association has warned that GE may speed the evolution of microbes resistant to antibiotics. The U.K. Ministry of Agriculture warned that antibiotic-resistant genes in GE corn could render useless eight powerful antibiotics used by doctors to fight fatal diseases. According to the warning, the antibiotic-resistant genes are so powerful they could degrade an antibiotic in the human gut within 30 minutes. Allergens According to the FDA, in Federal Register 22987, "Genetic engineering may transfer new and unidentified proteins from one food into another, triggering allergic reactions. Millions of Americans who are sensitive to allergens will have no way of identifying or protecting themselves from offending foods. Allergic reactions can cause more than a simple discomfort-they can result in life-threatening anaphylactic shock." Unintended Effects Inherent to the Technology The random insertion of foreign genes into the genome can create unexpected and unintended effects. In mammalian cells, these effects can include cancer, according to the World Scientists' Statement (WSS): Supplementary Information on the Hazards of Genetic Engineering. Moreover, the effects can spread through the host genome from the site of insertion. Interactions between Foreign Genes of the Host Organism Genes don't function in isolation. Food safety risks include unintended effects, such as new toxins and allergens, or changes in concentrations of existing toxins and allergens. As explained by the FDA in Federal Register 22987: "Many plants naturally produce a variety of compounds that are toxic to humans or alter food quality. Generally, these are present at levels that do not cause problems. Combining plants and animal species in genetic engineering may create new, much higher levels of these toxins." Soybeans contain at least 16 proteins that can cause allergic reactions, which vary among different ethnic groups. A major allergen, with antinutritional effects, trypsin-inhibitor, was found to be 26.7 percent higher in Monsanto's transgenic soybeans. (4) Even so, the beans were approved for market on the basis of "substantial equivalence" to their unmodified counterparts. (5) The same transgenic soy reduced growth rate of male rats and increased milk fat in cows that consumed the beans. (6) A study by the York Nutritional Laboratory, Europe's leading specialists in food sensitivities, revealed a 50 percent increase in soy allergies during the past year-a period when the percentage of GE beans in the total soy crop jumped dramatically. For the first time in 17 years of testing, soy ranked among the top ten allergenic foods. Researchers did not establish a causal tie between genetic engineering and soy allergies. They did note, however, that soy is the most common GE food, and their findings indicate that GE food could have a tangible, harmful impact on the human body. Such findings are of particular significance for vegetarians who rely heavily on soy products as protein sources. (7) Dr. A. Pusztai, a world renowned researcher on plant lectins at Rowett Institute in Scotland, found that rats eating lectin-producing GE potatoes suffered significant damage to their immune systems, thymuses, kidneys, spleens, and guts, according to another scientist, Dr. Stanley Ewen. Dr. Ewen said that the Cauliflower Mosaic Virus (CaMV), a commonly used production aid, or vector, in gene splicing may have caused serious damage to the stomach and internal organs of the rats in Pusztai's study. Roundup Ready soybeans, Bt corn, and most other GE crops use CaMV as a gene-splitting vector. (8) After releasing his findings, Pusztai was fired and his work discredited by the government-funded Rowett Institute. In February of 1999, front-page headlines announced that a panel of 20 international scientists verified his findings. According to the British press, Pusztai's firing and the scientific cover-up by the UK government resulted from White House pressure on Tony Blair to keep British and EU markets open to Monsanto and other biotech companies. (9) The Canadian equivalent of the FDA and EU's Scientific Veterinary Committee recommended against foods from cows treated with Bovine Growth Hormone (rBGH). Between them, they examined evidence of potential cancer hazards: rats absorbed rBGH, developed immunological reactions, and formed cysts in their thyroids that infiltrated the prostate; and milk contained increased levels of the hormone IGF-1, which is linked to cancer. (10) A minority of U.S. dairy farmers still inject cows with rBGH. The following are a few other unintended results of GE crops so far: ú Impaired sense of smell and shortened lifespan in bees consuming pollen from GE plants ú Changed hormone levels and altered milk content in cows eating GE soybeans ú Sickness in cattle given Bovine Growth Hormone ú Unexpected and unpredictable change in color of GE petunias ú Failures of cotton and other GE crops ú Toxicity of Bt to non-target species, such as Monarch caterpillars ú Toxicity moving up the food chain, causing death or impaired health in non-target species consuming insects that fed on Bt crops (11) Hazards Arising from the Unintended Transfer of Introduced Genes to Other Organisms and Species Evidence suggests that DNA is not broken down rapidly in the gut. Transgenes and antibiotic-resistant marker genes may therefore spread bacteria in the gut. New Scientist reported that antibiotic-resistant marker genes from GE bacteria can be transferred to indigenous bacteria in an artificial gut. Researchers have also found that when viral DNA is fed to mice, large fragments can pass into the bloodstream and into white blood cells, spleen and liver cells, and can link with mouse DNA. (12, 13) Viral DNA is more infectious than the intact virus. For example, intact human polyma virus injected into rabbits had no effect, whereas, injection of the naked viral DNA resulted in a full-blown infection. (14, 15, 16) The World Scientists' Statement warns that released transgenes have the potential to multiply and recombine beyond control. Once released into the environment, polluting genes cannot be recalled. A recent report in Nature suggests that transgenes may be as much as 30 times more likely to escape than the plant's own genes. Evidently, the same mechanisms that enable the vector carrying the foreign genes to insert into the host genome can also mobilize it to jump out again to reinsert at another site or to infect other cells. (17) Already documented is the spread of transgenes and marker genes to wild relatives by cross-pollination, creating superweeds. Unfortunately, some of the most troublesome weeds, such as wild grains, are close relatives of food crops. (17) In some African uplands, for example, rice crops grow adjacent to wild rice species that constitute a serious cause of crop loss. Eventually, superweeds affect the food supply by requiring more frequent and more toxic applications of herbicides to food crops. (18) Transfer of transgenes and antibiotic-resistant marker genes from genetically engineered crop plants into soil bacteria and fungi have been documented in the laboratory. Evidence exists that DNA released from dead and live cells are readily broken down, but retain the ability to spread antibiotic-resistant marker genes to pathogenic organisms in the environment. They may also contribute to generating new viral pathogens. (19) Transgenes can also pollute conventional crops, endangering the consumer's right to choose. European labs detected traces of GE corn in organic corn chips from Prima Terra, Inc., of Hudson, Wisconsin. Some of the corn supplied to Prima Terra from a certified organic supplier was contaminated with gene-altered corn, attributed to engineered pollen-blown GE corn at a neighboring farm. (20) [CONCLUDED IN PART TWO] -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: [email protected] Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <[email protected]>
