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Concerns About GMOs

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A growing body of research suggests that genetically modified organisms (more commonly referred to as GMOs) may be doing more harm than good when it comes to human health and the health of the environment. A recent study coming out of Iowa State University, for example, found that Monsanto's genetically modified corn may have led to the rise of pesticide-resistant "superbugs," which could result in some farmers using even harsher pesticides on their fields.

Read on to learn more about this and other issues that raise red flags about GMOs.

GMOs are organisms that have been created through the application of transgenic, gene-splicing techniques that are part of biotechnology. These methods for moving genes are also referred to as genetic engineering (GE).

This relatively new science allows DNA (genetic material) from one species to be transferred into another species, creating transgenic organisms with combinations of genes from plants, animals, bacteria, and even viral gene pools. Mixing genes from different species that have never shared genes in the past makes GMOs and GE crops unique. It is impossible to create such organisms through traditional crossbreeding methods.

Because of this uniqueness, there are many unknowns about genetically engineered (GE) crops and GMOs.

Asserting that food from GE crops was “substantially equivalent” to food from non-GE crops, the United States government first approved GE crops nearly 20 years ago depending largely on the studies provided by the companies developing the new technology.  The United States went ahead with approvals although no human trials had ever been conducted to assess the safety and allergenicity of these novel proteins.

Governments outside the United States have proceeded with more caution, preventing GE crops from being planted because of outstanding concerns about environmental and/or food safety implications. Since GE crops were first approved in the United States, food allergies have risen dramatically, in step with GE crop market penetration . For instance, according to a data brief published October 2008 by the Centers for Disease Control and Prevention, the prevalence of reported food allergies in the United States increased 18 percent among children under age 18 years from 1997 to 2007. Although no direct links have been made to GE crops, a report by the Pew Initiative on Food and Biotechnology  points out that existing research focuses on known allergens such as peanuts and milk, and there are almost no studies examining the allergenicity of novel proteins potentially introduced by foods created through biotechnology.

A major area of concern focuses on unintended consequences. For instance, some major problems with GE crops are already emerging. The spread of resistant weeds has driven herbicide use up sharply, increasing human health and environmental impacts and raising farmer costs. Also, many GE crops are more prone to plant diseases, and some suffer micro-nutrient deficiencies because of subtle changes in soil microbial communities.

There is mounting evidence that GMOs from GE crops are showing up where they were never used. Contamination is a real threat, particularly in crops that easily cross-pollinate, such as corn and canola.

Meanwhile, more and more studies are confirming that there are genuine concerns about their use. The following looks at some of the concerns that are being raised.

•    Impact of pesticide use, yields
In November 2009, The Organic Center issued a Critical Issue Report  on the impact of the adoption of GE corn, soybean and cotton crops on U.S. pesticide use. The most striking finding: with the use of GE crops was the application of an additional 318.4 million pounds of pesticides in the United States over the first 13 years of their commercial use (1996-2008).

Data from the 1996 through 2008 annual pesticide use surveys done by the USDA’s National Agricultural Statistics Service (NASS) showed that Bt corn and cotton reduced insecticide use by 64.2 million pounds over the 13 years. However, herbicide-tolerant crops increased herbicide use by a total of 382.6 million pounds over the 13 years. Herbicide-tolerant soybeans increased herbicide use by 351 million pounds, accounting for 92 percent of the total increase in herbicide use across the three herbicide-tolerant crops.

The 318.4 million pound increase in overall pesticide use represents, on average, an additional 0.25 pound of pesticide active ingredient for every GE trait acre planted over the first 13 years of commercial use.

Although overall pesticide use decreased in the first three years of commercial introduction of GE crops, pesticide use increased by 20 percent in 2007 and 27 percent in 2008. There are two major factors for this: the emergence and rapid spread of weeds resistant to glyphosate due to excessive reliance on the herbicide, and incremental reductions in the average application rate of herbicides applied on non-GE crop acres.

•    GMOs persist in waterways: A study by University of Notre Dame ecologist Jennifer Tank and colleagues published in 2010  has found that streams throughout the Midwest receive transgenic materials from corn crop byproducts even six months after harvest. In a 2007 paper in the Proceedings of the National Academy of Sciences (PNAS) , Tank and other researchers had shown transgenic materials from corn pollen, leaves and cobs do, in fact, enter streams in the agricultural Midwest and can be subsequently transported to downstream water bodies. Their later study, published in the Oct. 12, 2010, edition of PNAS, investigated the fate and persistence of the material and its associated Cry1Ab insecticidal protein in a survey of 217 stream sites in northwestern Indiana six months after crop harvest. “Our study demonstrates the persistence and dispersal of crop byproducts and associated transgenic material in streams throughout the Corn Belt landscape even long after crop harvest,” the researchers concluded.

•    GE in the wild: Researchers at the University of Arkansas, North Dakota State University and the Environmental Protection Agency have found evidence that GE crop plants can survive and thrive in the wild. Reporting the findings at the 95th annual meeting of the Ecological Society of America , scientists reported that they had found that more than 80 percent of canola plants sampled from more than 1,000 miles of roadsides around North Dakota were inadvertently genetically engineered to tolerate herbicides, either glyphosate or glufonisate. In addition, two of the plants analyzed contained two transgenes, indicating that they had cross-pollinated. “These observations have important implications for the ecology and management of native and weedy species, as well as for the management of biotech products in the U.S.,” the researchers concluded.

•    Resistance of insect pests: In 2010, Monsanto reported to the Genetic Engineering Approval Committee in India that pink bollworms, a common insect pest that feeds on cotton, have developed resistance to its GE cotton variety Bollgard I in Gujarat, India . The company noted it had detected the resistance during field monitoring in the 2009 cotton season. The GE crop contained the Cry1Ac gene derived from the bacterium Bacillus thuringiensis (Bt).

•    Weed resistance: A 2010 report issued by The National Academies’ National Research Council  warns that GE crops could lose their effectiveness and develop more weed problems as weeds evolve their own resistance to glyphosate, unless farmers use other proven weed and insect management practices. It reported to date that at least nine species of weeds in the United States have evolved resistance to glyphosate since GE crops were introduced.

•    Round-up resistant weeds: A New York Times article  by William Newman and Andrew Pollack (May 4, 2010) reported on the increase of superweeds that are resistant to Round-up.

•    Herbicide resistance: A survey by researchers at the Department of Crop Sciences, University of Illinois in Urbana, has found that Amaranthus  tuberculatus (more commonly known as waterhemp), a major weed in crop fields in the Midwestern United States, has developed multiple herbicide resistance, including to glyphosate (Roundup). In their research article published in the Journal of Agricultural and Food Chemistry , they noted, “Herbicide resistance in A. tuberculatus appears to be on the threshold of becoming an unmanageable problem in soybean.”  They added, “On the basis of A. tuberculatus’s history, there is no reason to expect it will not evolve resistance to glufosinate if this herbicide is widely used. If this happens, and no new soybean post-emergence herbicides are commercialized, soybean production may not be practical in many Midwest U.S. fields.” At least 21 weed species have developed resistance to the herbicide glyphosate (Roundup) and some weeds are also developing resistance to alternative herbicides, according to articles published in the May-June 2011 issue of Weed Science . For example, researchers at the University of Georgia in Tifton found multiple resistances in Palmer amaranth to glyphosate and the herbicide pyrithiobac. In addition, research confirmed resistance of Italian ryegrass in hazelnut orchards in Oregon to glufosinate ammonium, a non-selective broad-spectrum herbicide. Still another study confirmed the first documented glyphosate-resistant Johnson grass biotype in West Memphis, AR. “The herbicide resistance issue is becoming serious,” wrote William K. Vencill, journal editor, adding, “It is spreading out beyond where weed scientists have seen it before.”

•    Organ failure (rats): A study  analyzing the effects of GE foods on mammalian health linked three GE corn varieties to organ failure in rats. The researchers led by Gilles-Eric Séralini of CRIIGEN and the University of Caen in France found new side effects linked with GE corn consumption that were sex- and often dose-dependent. These effects mostly occurred with the kidney and liver, while other effects were noticed in the heart, adrenal glands, spleen and hematopoietic system. The researchers concluded that these data highlight signs of hepato-renal toxicity, possibly due to the new pesticides specific to each GE corn.

•    Glyphosate and birth defects: Research published Aug. 9, 2010 , confirms that glyphosate-based herbicides cause malformations in frog and chicken embryos at doses significantly lower than those used in agricultural spraying and well below maximum residue levels in products currently approved in the European Union. Glyphosate is the active ingredient in Roundup. Publishing the research were researchers led by Professor Andrés Carrasco, director of the Laboratory of Molecular Embryology at the University of Buenos Aires Medical School and member of Argentina’s National Council of Scientific and Technical Research. “The findings in the lab are compatible with malformations observed in humans exposed to glyphosate during pregnancy,” Carrasco reported at a press conference during the 6th European Conference of GMO Free Regions. He explained that most of the safety data on glyphosate herbicides and GE soy were provided by industry and are not independent. Carrasco began researching the embryonic effects of glyphosate after seeing reports of high rates of birth defects in rural areas of Argentina where GE Roundup Ready soybeans are grown in large monocultures sprayed regularly from airplanes.

•    Impacts on animal health. Researchers from Greece  reported that animal toxicology studies of GE foods indicate they can have toxic hepatic, pancreatic, renal and reproductive effects. Also, the use of recombinant growth hormones or its expression in animals should be re-examined since it has been shown that it increases IGF-1 which may promote cancer.

•    Serious human health risks.  The American Academy of Environmental Medicine, in a 2009 Genetically Modified Foods Position Paper , called for a moratorium on GE foods and warned that “GM foods pose a serious health risk in the areas of toxicology, allergy and immune function, reproductive health, and metabolic, physiologic and genetic health.” This position paper cites animal studies that indicate such health risks associated with GM food consumption as infertility, immune dysregulation, accelerated aging, dysregulation of genes associated with cholesterol synthesis, insulin regulation, cell signaling and protein formation, and changes in the liver, kidney, spleen and gastrointestinal system. “Because of the mounting data, it is biologically plausible for genetically modified foods to cause adverse health effects in humans,” the report notes, listing citations for numerous peer-reviewed studies as backup.

•    Bt toxin in human blood. Most recently, a study  accepted for publication in the journal Reproductive Toxicology conducted by scientists at the University of Sherbrooke in Canada reports the presence of Bt toxin, widely used in GE crops, in human blood. Although scientists and multinational corporations promoting GE crops have maintained that Bt toxin poses no danger to human health as the protein, Cry1Ab, breaks down in the human gut, the findings from this study show this does not happen. Instead, it was found circulating in the blood of pregnant and non-pregnant women. The study also detected the toxin in fetal blood. Cry1Ab toxin was detected in 93 percent and 80 percent of maternal and fetal blood samples, respectively, and in 69 percent of tested blood samples from non-pregnant women.

Although biotechnology interests often argue that GE crops have not caused a single instance of harm to human health or the environment, there is mounting research showing that GE crops are not harmless, as evidenced by the research cited above. However, GE foods are not labeled.

As a result, the Organic Trade Association and many consumer groups have long called for labeling GE foods in the marketplace. But this concern goes beyond consumers and organic interests. In 2010, for instance, the Indiana State Medical Association (ISMA, representing approximately 8,300 physicians in every county in Indiana) resolved that it would seek legislation requiring that any foods containing genetically engineered ingredients be clearly labeled .

ISMA’s resolution, discussed at its 2010 annual meeting, noted that 40 countries require labeling of GE food, including the European Union, Australia, Japan, Russia, Chia, New Zealand, Brazil and South Africa. In addition, the American Public Health Association, American Nurses Association, the British Medical Association and the Irish Medical Organization all support the labeling of GE food products.

Meanwhile, the challenge for consumers who don’t want to eat foods made with GMOS is to know what food products to avoid. The crops most often genetically modified in the United States—as well as the ingredients made from them—are corn, soybeans, canola, sugar beets and cotton. Thus, the following ingredients on labels, if not labeled as non-GMO or organic, are likely genetically modified.
•    Corn syrup, starch, oil, meal, gluten
•    Soy lecithin, protein, flour, isolate and isoflavone
•    Sugar (unless it is made from cane)
•    Vegetable oil
•    Cottonseed oil


While genetic events are traceable through the supply chain via contracts and analytical testing, because GE foods are not labeled, they are not readily identifiable by consumers in the marketplace. Additionally the contractual information, test results and genetic information are not readily available to researchers and scientists. This greatly limits the ability to assess environmental and public health safety over time. As patented products, the primers and gene sequences related to GE crop events are not readily disclosed—greatly limiting independent scientific scrutiny. Prohibitions on land-grant universities conducting research on GE crop events without permission from patent holders further exacerbates the dearth of independent research.

There continues to be emerging evidence of environmental and public health concern from the adoption of GMOs in agriculture.


Food Allergy Among U.S. Children: Trends in Prevalence and Hospitalizations, Amy M. Branum and Susan L. Lukacs, U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, October 2008 (http://www.cdc.gov/nchs/data/databriefs/db10.pdf).

Pew Initiative on Food and Biotechnology, “A Snapshot of Federal Research on Food Allergy: Implications for Genetically Modified Food,” June 11, 2002 (http://www.pewagbiotechn.org/research/allergy.pdf.)

“Impacts of Genetically Engineered Crops on Pesticide Use in the United States: The First Thirteen Years,” by Charles Benbrook

Jennifer L. Tank, Emma J. Rosi-Marshall, Todd V. Royer, Matt R. Whiles, Natalie A. Griffiths, Therese C. Frauendorf, and David J. Treering, “Occurrence of maize detritus and a transgenic insecticidal protein (Cry1Ab) within the stream network of an agriculturl landsacpe,” PNAS 107 (41): 17645-17650 (Oct. 12, 2010).

E.J. Rosi-Marshall, J.L. Tank, T.V. Royer, M.R. Whiles, M. Evans-White, C. Chambers, N.A. Griffiths, J. Pokelsek, and M.L. Stephen, “Toxins in transgenic crop byproducts may affect headwater stream ecosystems,” PNAS 104 (41): 16204-16208 (Oct. 9, 2007).

Meredith G. Schafer, Andrew X. Ross, Jason Londo, Connie A. Burdick, E. Henry Lee, Steven E. Travers, Peter K. Van de Water, and Cynthia L. Sagers, research reported at the 95th Ecological Society of America in August 2010 (http://eco.confex.com/eco/2010/techprogram/P27199.HTM.

Science, March 19, 2010, “Hardy Cotton-Munching Pests Are Latest Blow to GM Crops,” by Pallava Bagla.

“The Impact of Genetically Engineered Crops on Farm Sustainability in the United States,” The National Academies’ National Research Council, 2010.


Patrick J. Tranel, Chance W. Riggins, Michael S. Bell, and Aaron G. Haber, “Herbicide Resistances in Amaranthus tuberculatus: A Call for New Options,” Jouranl of Agricultural and Food Chemistry November 2010.

May-June 2011 Weed Science ((http://allenpress.com/publications/journals/wees; http://www.wssajournals.org/doi/pdf/10.1614/WS-D-10-00132.1).

Chemical Research in Toxicology (http://pubs.acs.org/doi/abs/10.1021/tx1001749

Artemis Dona & Ioannis S. Arvanitoyannis, “Health Risks of Genetically Modified Foods,” Critical Reviews in Food Science and Nutrition, February 2009, pages 164-175).

American Academy of Environmental Medicine, Genetically Modified Foods Position Paper, May 8, 2009 (http://www.aaemonline.org/gmopost.html)

Aziz Aris and Samuel Leblanc, “Maternal and fetal exposure to pesticides associated to genetically modified foods in Eastern Townships of Quebec, Canada, Reproductive Toxicology (article in press) (http://somloquesembrem.files.wordpress.com/2010/07/arisleblanc2011.pdf).

http://www.ismanet.org/pdf/convention/2010/All-resolutions.pdf; http://www.ismanet.org/resolutions/actions09.html


International Journal of Biological Sciences (http://www.biolsci.org/v05p0706.pdf)