(Beyond Pesticides, September 21, 2012) A new French study reports that rats fed a diet of Roundup-tolerant genetically modified (GM) corn had an increased risk of developing tumors, suffering organ damage and dying prematurely. The study is the first animal feeding trial studying the lifetime effects of exposure to Roundup tolerant GM corn and has prompted the European Food Safety Authority to look into the study‚Äôs results. However, it is also being criticized by some other scientists who said the methodology was flawed and that other research had not found similar problems.
The study, “Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize,‚ÄĚ which is being published in the peer-reviewed journal Food and Chemical Toxicology, was led by Gilles-Eric S√©ralini, PhD, at the University of Caen in France. The study followed 200 rats for two years, the life-span of the rat, but far longer than the typical 90-day feeding studies used in regulatory assessments and subsequent approval of GM crops. The rats were fed different amounts of NK603 corn developed by Monsanto to be resistant to the herbicide Roundup. In some cases, the corn had been sprayed in the field with Roundup. Other rats were given different doses of Roundup in their drinking water, with the lowest dose corresponding to what might be found in tap water in the U.S.
Female rats developed fatal mammary tumors and pituitary disorders. Males suffered liver damage, developed kidney and skin tumors and experienced problems with their digestive system. The team also found that even the lowest doses were associated with severe health problems. Up to 50% of males and 70% of females died prematurely compared with only 30% and 20% in the control group, and across all treatments and both sexes, researchers found treated rats developed 2-3 times more large tumors than the control group.
‚ÄúThe results were really alarming,‚ÄĚ Dr. S√©ralini said. According to Dr. S√©ralini, the tumors did not develop until well after 90 days, meaning they might have been missed by shorter studies.
However, many have criticized the study‚Äôs methods and the ideological manner in which it was being presented. There are complaints that there is not enough data on the rats’ actual diet; that the sample size was too small; and that the rats in question are “very prone to mammary tumors particularly when food intake is not restricted.” The statistical methods used are also called ‚Äúunconventional” and “inadequate.”
However, the study does underscore the need for more research on the long-term health effects of GM crops. Previous studies with various types of GM crops have reported higher incidents of allergies, liver and kidney damage, and significantly reduced fertility over three to four breeding cycles within one generation in mice.
‚ÄúWe’ve never done this kind of study before, and we should have been doing it a long time ago,‚ÄĚ said Andrew Kimbrell, of the Washington-based Center for Food Safety, a group critical of the regulations surrounding genetically engineered crops. ‚ÄúI’ve heard for two decades that no one’s shown any health impacts with GMO foods. As of September 19, 2012, that’s no longer true.‚ÄĚ
This study comes at a time when efforts to block the passage of California‚Äôs Prop 37, which would require mandatory labeling on GM foods, is heating up. The Proposition 37 campaign, which is supported by organic food companies and health groups, has been vastly outspent by a campaign to defeat the ballot initiative funded by millions of dollars in donations from chemical companies and food manufacturers such as Monsanto, DuPont, Bayer and Nestle. However, polls taken earlier this year show that 91% of consumers favor labeling for GM foods, with 81% of those ‚Äėstrongly‚Äô in favor of enacting these requirements.
Currently, there are commercially available Roundup-tolerant seed varieties for corn, soybeans, canola, sorghum, and cotton, in addition to sugar beets, and recently approved Roundup-tolerant alfalfa. Earlier this year, Dow AgroSciences and Bayer CropScience petitioned USDA to yet again deregulate varieties of soybean and corn tolerant to multiple pesticides including 2,4-D and dicamba. In its petition, Dow states that 2,4-D is increasingly important for chemical farmers because of the presence of weeds that have developed resistance to Roundup, as a result of the widespread use of Monsanto‚Äôs GM roundup-tolerant crops. Farm research groups are also concerned with the impact of GM crops on organic farmers, whose organic crops are already at risk of contamination with Monsanto‚Äôs genetic material from pollen drift.
Roundup, whose active ingredient is glyphosate, has been linked to a number of serious human health effects, including increased cancer risk, neurotoxicity, and birth defects, as well as eye, skin, and respiratory irritation. One of the inert ingredients in product formulations of Roundup, polyoxyethyleneamine (POEA), kills human embryonic cells. It is also of particular concern due to its toxicity to aquatic species as well as instances of serious human health effects from acute exposure. 2, 4-D is a highly toxic herbicide which has been linked to cancer, reproductive effects, endocrine disruption, and kidney and liver damage. It is also neurotoxic and is toxic to beneficial insects (such as bees), earthworms, birds, and fish. Scientific studies have confirmed significantly elevated rates of non-Hodgkin‚Äôs lymphoma for farmers who use 2, 4-D.
While the long-term health effects of eating GM crops are unclear, the environmental impacts of this technology are currently being documented. Increased herbicide use, water contamination, the spread of herbicide-resistant ‚Äúsuperweeds,‚ÄĚ and the loss of habitat and wildlife species as a result of increased pesticide use has all been attributed to the widespread use of GM crops.
For more information on genetically engineered food, read ‚ÄúGenetically Engineered Food Failed promises and hazardous outcomes,‚ÄĚ from Pesticides and You, or go to our Genetic Engineering web page.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.