Genetically-Engineered Foods - How It Is Done, What Are The Risks

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Genetically-Engineered Foods - How It Is Done, What Are The Risks By Barbara Keeler and Shirley Watson DC, CCN, DACBN, QME
9-24-00


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 foods were quietly introduced into the market place and rapidly permeated it. Today, there are three GM varieties of soy, 10 varieties of corn, papaya, yellow neck squash, canola, potatoes, tomatoes, dairy, and animal products already on the tables of most consumers, with more than a hundred expected soon. According to most estimates, 60-70% of all processed foods contain genetically modified ingredients, including proteins previously absent from human diets.

Patients may look to their health care providers for advice about GE foods. Like most consumers, patients may be understandably confused 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 citizens in Ireland, France, and California ravaged Monsanto's GE food crops or GE seeds. Why, they might ask, did a Greenpeace delivery truck that dump four tons of US GE soybeans on the front steps of Prime Minister Tony Blair, one of UK's few supporters of GE foods, with a banner reading "Tony, Don't Swallow Bill's Seed."

Authoritative regulatory bodies present conflicting views as well. United States (US) Food and Drug Administration (FDA) policy is that most genetically engineered foods are substantially equivalent to their unmodified counterparts and do not require labeling or special premarket testing. By contrast, The Canadian equivalent to FDA and the Codex Alimentarius Commission, the U.N. Food Safety Agency, 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 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, decisions about GE foods may become more relevant. Consumer demand gives industry incentives 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), trasgenic, 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, desirable characteristics not found in the original, unmodified organism (UMO). Eighty percent of biotechnology research is directed at modification of food plants; the remaining 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 UMO'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 Agrobacterium 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 the chromosomes of some target 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 random. Only in a small percentage of the treated cells are transgenes successfully incorporated into the DNA. In order 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 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.

[SOCIAL] and economic hazards result from intensifying corporate control on food production and distribution, which threatens the variety and distribution of the food supply. A particular concern is its potential impact on poverty and hunger in the developing world.

POTENTIAL HAZARDS FROM TRANSGENES AND GENE PRODUCTS SELECTED

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. Scientist 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 (FDA) 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 nontarget insects.

HERBICIDE RESISTANCE GENES Of all genetically-altered crops last year, 71% 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 nightmare litany of adverse health effects. The risks of these GE crops will be examined later in this article.

ANTIBIOTIC-RESISTANCE GENES In Federal Register 22988, the US FDA warns of "Decreased effectiveness of antibiotics due to antibiotic-resistance 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 UK Ministry of Agriculture warned that antibiotic resistance genes in GE corn, could render useless eight powerful antibiotics used by doctors to fight fatal diseases. According to the warning the antibiotic resistance genes are so powerful they could degrade an antibiotic in the human gut within 30 minutes.

ALLERGENS According to FDA, on Fed I 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 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 AND 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 which do not cause problems. Combining plants and animal species in genetic engineering may create new and 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% higher in Monsanto's transgenic soybeans. Even so, the beans were approved for market on the basis of "substantial equivalence" to their unmodified counterparts. The same transgenic soy reduced growth rate of male rats and increased milk fat in cows consuming the beans.

[A STUDY BY THE YORK NUTRITIONAL LABORATORY, EUROPE'S LEADING SPECIALISTS ON FOOD SENSITIVITY, 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 10 ALLERGENIC FOODS. RESEARCHERS DID NOT ESTABLISH A CAUSAL TIE BETWEEN GENETIC ENGINEERING AND SOY ALLERGIES. HOWEVER, THEY DID NOTE THAT IS THE MOST COMMON GE FOOD, AND THAT THEIR FINDINGS INDICATE THAT GE FOOD COULD HAVE A TANGIBLE, HARMFUL IMPACT ON THE HUMAN BODY. SUCH FINDINGS ARE OF PARTICULARLY SIGNIFICANCE FOR VEGETARIANS WHO RELY HEAVILY ON SOY PRODUCTS AS PROTEIN SOURCES.]

Dr. 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 Anther scientist, Dr. Stanley Ewen, said that the Cauliflower Mosaic Virus, a commonly used vector or production aid 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 are produced using the CaMV as a gene-splicing vector.

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 his findings were verified by a panel of 20 international scientists. According to the British press, Pusztai's firing and the scientific coverup 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.

The Canadian equivalent of 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 which infiltrated the prostate; and milk contained increased levels of the hormone IGF-1, which is linked to cancer. A minority of US dairy farmers still inject cows with rBGH.

Following are a few other unintended results of GE crops so far.

* impaired sense of smell and shortened lifespan in bees consuming pollen from GE plants;

* changed hormone levels and altered milk content in cows eating GE soybeans;

* sickness in cattle given Bovine Growth Hormone;

* unexpected and unpredictable change in color of GE petunias;

* failures of cotton and other GE crops;

* toxicity of Bt to nontarget species such as monarch caterpillars;

* toxicity moving up the food chain, causing death or impaired health in nontarget species consuming insects that fed on Bt crops.

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 resistance marker genes may therefore spread to 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. Viral DNA is more infectious than the intact virus. For example, intact human polyoma virus injected into rabbits had no effect, whereas, injection of the naked viral DNA resulted in a full-blown infection.

WSS 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.

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. 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.

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 not 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.

Transgenes can also pollute conventional crops, endangering consumer 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 on a neighboring farm.

WHAT CAN BE DONE TO INSURE SAFETY?

FDA does little to insure safety. Premarket testing is voluntary, except for GE crops registered as pesticides with EPA. FDA recommends only that developers conduct a few in vitro tests to assess whether the transgenic protein is similar in biochemical characteristics to a handful of common allergens. In vitro tests are specific for single compounds or antigens. For transgenic proteins of indeterminate allergenicity, for example, those with genes derived from organisms not commonly consumed by humans, FDA does not require any empirical analysis.

What analysis is performed is often flawed. For example, biotech companies test herbicide tolerate GE seeds BEFORE they are treated with the herbicide. Recent tests show biochemical changes, such as alterations in phytoestrogen levels, take place in GE seeds AFTER they are treated with the herbicide glyphosate.

The inadequacy of even the voluntary testing recommended by FDA is clear from the conclusions of a 1994 Conference on Scientific Issues Related to Potential Allergenicity in Transgenic Food Crops hosted by the US FDA, EPA, and Department of Agriculture (USDA). According to the scientists, in vitro tests cannot screen for the vast diversity of unique allergens and toxins of unknown structure and function that may be created through GE manipulations, nor can they assess the potential allergenicity of proteins derived from sources not normally part of the human food supply or that are generated through the genetic engineering process.

The experts also maintained that no adequate animal models exist for assessing human allergenicity. Moreover, use of human subjects in assessing food allergenicity has its own challenges-- for example, the large numbers of subjects it would require because of the low incidence of reactions in the human population to any given allergen.

In December of 1998, scientists representing twenty- nine industrialized countries concluded that effective testing of GE food would require innovative approaches. Test subjects can't consume 100-1000 times likely intake, as is done when testing drugs, to insure safety. Instead, food safety testing should use doses that approximate the normal dietary use of food, maintaining a balanced diet for the test subjects. Monitored long-term testing would be necessary to detect long-term effects. Dr. John Fagan considers it essential to establish clear guidelines for premarket assessment of health and environmental effects of each GMO. Fagan is a molecular biologist who for twenty- two years conducted research in recombinant DNA for the National Institute of Health. He received research grants totaling $2.5 million. Once he recognized the causes for concern, he returned $600,000 in 1994 and withdrew a proposal for $1.25 million. He has since developed testing techniques to identify GE foods in the market place.

Fagan recommends that, before human trials, tests with rodents should determine that a genetic food is not acutely poisonous. Then, a graduated series of feeding studies with human v olunteers [SHOULD] be conducted to screen for toxic and anti-nutrient action of the GE foods that may be slightly less acute, or require longer exposure to become apparent. However, he emphasizes that the best testing methods available cannot guarantee the safety of a new GE product.

A further testing challenge is that, as Ralph Waldo Emerson points out, "Science can not be considered separately from the people doing the science. There is ultimately no science, only scientists."

Who are the scientists? The industrialization of academic research imperils the objective search for truth about the risks and benefits of GE crops. Who has the resources and incentive to fund research about GE crops-- primarily affected industries. Who funds the peers who review the research? According to news reports, funders of product research threaten loss of funding to force their researchers to suppress or delay publication of negative evidence.

Moreover, studies may be evaluated by biased panels. At the FDA, such panels contain representatives of the affected industries, and the revolving door between the personnel departments of the FDA and such regulated companies as Monsanto is well documented.

A recent example of potential bias surfaced when National Academy of Sciences formed a panel to study GE plants producing pesticides, such as bacillicus thuringiensis (Bt) toxins, in their cells. At issue was that EPA regulates these crops as pesticides; suppliers make pesticide claims, and plants are engineered to kill insects. Before the panel was finalized, a study director, Dr. Michael Phillips[,] had already told callers that such regulation is inappropriate. Toward the end of the study, Phillips left the National Academy of Sciences to work for the trade association, Biotechnology Industry Organization.

Of 12 panel members, seven had past or present financial ties to biotech or pesticide industries. An attorney and a scientist had represented Monsanto and the biotech industry against federal regulators, four other members received direct or indirect funding from GE seed producers such as Monsanto and Novartis, and another was a consultant for the pesticide industry.

More to the point, the time for unbiased studies assessing risks and benefits is before, not after, release of these organisms into the environment and the diets of consumers. All factors considered, many nonindustry scientists recommend taking a long look before releasing any more GE crops.

WHAT ARE THE CONSEQUENCES OF DELAY?

What has the world to lose by a "go slow" approach to allow for careful, study of long-term safety? What if evidence shows that Genetic engineering, with the current state of technology, is ill-advised?

Biotech companies and some US government leaders would have consumers believe they would be denied tastier, more nutritious food. Yet so far most GE crops in the present food confer no benefits on consumers, but tolerate a specific herbicide made by the company engineering the seeds; for example, Roundup Ready soybeans, which now account for 37% of the US soybean crop. With few exceptions, the rest produce Bt toxins. Some enhance shelf life or transportability. Consumers would not miss these products.

Indeed, scientists and economist[S] raise concern that consumer choice could be limited by extensive corporate integration within the agriculture/food-supply chain. In its September, 1999 issue, CONSUMER REPORTS identified the six companies that dominate research and development in plant genetic engineering as Monsanto, DuPont, Novartis, Austra-Zeneca, and Aventis (formed by the merger of Rhone Poulenc with the shareholders of AgrEvo: Hoechst and Schering). Between them they also own a substantial and growing portion of the global seed market, and some own food-processing companies through acquisition or joint ventures. Such integrated consolidation could reduce the diversity of food products which ultimately reach the supermarket shelves.

A compelling argument is that world will not be able to feed its hungry. Who among us has not responded with the deepest sympathy and concern for those starving wide-eyed young children flashed upon television screens from the outer reaches of this planet. The world is hungry and we need to address this heartbreaking and devastating situation. The biotech industry plays upon this deep concern by telling us that without GE technology we will never feed the world populace. Only with the increased production and nutritional enhancement of this technology will all those hungry children find relief from their peril.

Yet the wide-spread growth in genetic engineering has not reduced hunger. Far from feeding the world, it is intensifying corporate control on food production and distribution which created poverty and hunger in the first place. Only the most negligible effort focussed on what less developed countries need: cheap, labor-intensive, robust and high-yielding staples for human food. The nature of GM crop development means that most research and development is undertaken by a relatively small number of large companies who dominate food engineering. Thus, the current focus is on herbicide tolerance and other requirements of labor-saving production by large farms in industrialized countries for developed markets. In areas with burgeoning populations, poverty reduction programs require raising, not lowering, demand for labor. Moreover, GE herbicide-tolerant seeds are more expensive than their unmodified counterparts, and of no benefit to farmers who cannot afford herbicides.

New technologies on the horizon promise to work against, rather than for, impoverished farmers. Gene use restriction technology, (GURT), commonly known as terminator technology, allows the seed producer to prohibit or restrict the use of farm-saved seeds. The seeds are programmed to produce deadly proteins late in their cycle. GURt insures that the seed either can not germinate, or may require another chemical to reactivate it, which would necessitate purchases of new seeds or chemicals each year from the major seed companies.

Some GURT relies on switch technology, in which a transgene construct has a promoter sequence that determines when and where in the plant the gene will be turned on. These promoters can be engineered for externally influence in some cases, such as a chemical application. Recent GURT technology targets seeds that won't germinate unless exposed to a specific chemical sold by the GE seed supplier.

Patents [FOR] GURT technology are owned jointly by the USDA and a corporation soon to be acquired by Monsanto. A new patent reveals that despite strong opposition to the US involvement with the GURT technology, USDA funding supports additional Terminator research at Purdue University.

Among the promises of genetic engineering, according to the biotech industry and their US government supporters, is reduction in the use of pesticides. In fact, Bt crops might render ineffective a natural pesticide that actually does reduce use of toxic chemicals. The bacteria called bacillicus thuringiensis, which produce Bt toxins naturally, have been used by organic growers in topical sprays since the early 1970s. Unlike the GE Bt producing plants, the bacteria can be applied judiciously, as needed, and at appropriate points in the growing process. Bt bacteria are relatively shortlived, and they secrete toxin in a form that becomes activated only in the alkaline digestive systems of certain worms and caterpillars.

By contrast, GE Bt crops secrete an active form of the toxin throughout the plant?s life cycle, including the harvest. These toxins in the plant tissue do not wash off, nor are they broken down by sunlight, as are their natural counterparts. Scientists estimate that by creating resistant pests, Bt crops will render the microbes ineffective within a few years.

According to Consumer Reports, in some cases herbicide tolerate cotton needed fewer herbicide applications, but herbicide tolerate corn required more. While Bt cotton required fewer pesticides for target insects, they required as many or more for nontarget insects.

AVOIDING GE PRODUCTS

At this point, GE products are not allowed in foods with the Organic label. Your patients can avoid GE foods by exclusive consumption of organic products, provided they can find everything they need [FROM ORGANIC SOURCES], and that organic crops are not polluted with transgenes from nearby GE crops.

In the United States a few food producers are attempting to provide some GE free products. For example, two of the largest US corn processors, A.E.Stanley Mfg. Co, and Arthur Daniel Midland Co, have declined to buy GE corn, which will make it easier for food companies to avoid GE corn in their processed foods. Honda Trading Co., which is a wholly owned division of the Japanese auto maker said that it will build a processing plant in the US, in Ohio, to sort and bag genetically modified free soybeans.

All of these developments may affect consumer choice. Genetic ID offers a technology developed by Dr. Fagan for genetic analysis of foods.

The authors join many leading scientists who recommend extensive study under controlled conditions before introducing GE crops into the food supply and the environment. We recommend that regulators require labels of products containing transgenes, so that consumers can weigh all evidence for themselves an make informed decisions. We further recommend that for the present, chiropractors advise their patients, to the extent possible, to avoid becoming nonconsenting test subjects in a mass experiment. As nontransgenic foods become available and identified, patients are well advised to choose them over foods with unknown genetic makeup.

Barbara Keeler has focused on health, nutrition, the environment, and regulatory affairs as a journalist and a contributor to health, nutrition, science, and social science textbooks.

Shirley Watson is Director of Education for the American Chiropractors Association's Council on Nutrition

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