Weighing GMO Safety

Report Examines Effects of GM Crops on Health, Environment, Society

Emily Unglesbee
By  Emily Unglesbee , DTN Staff Reporter
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A new report from the Academy of Science, Engineering and Medicine delved into the effects of genetically engineered crops on human, animal and environmental health. (DTN photo by Nick Scalise)

ROCKVILLE, Md. (DTN) -- Are genetically modified crops, future and present, good or bad for us? A committee of 20 academic scientists has pored over thousands of studies, public comments and expert presentations, all in the hopes of answering this pressing modern question.

The resulting 408-page report largely landed on "good" -- or at least, "not bad." The scientists found little to no evidence that GM crops are harmful to humans, livestock, the environment or society.

The report wasn't a glowing endorsement of all GM technology, however. The scientists also called for better data on agro-chemical use and concluded that GM crops alone cannot satisfy all of the world's future food needs, particularly for small-scale farmers in under-developed countries.

The committee of scientists also examined emerging genetic engineering techniques and recommended that future regulation focus less on the breeding "process," be it GM or traditional, and more on the characteristics of the new traits created.

The study was produced by the "Committee on Genetically Engineered Crops: Past Experience and Future Prospects," commissioned by the National Academies of the Sciences, Engineering and Medicine (known as the Academies). The goal was to produce a comprehensive, science-based and unbiased assessment of GM crops for policymakers and the public to reference and consider.


The scientists reviewed more than a thousand peer-reviewed scientific studies, fielded more than 700 comments from the general public, heard 80 presentations from a variety of experts, and submitted their report for review and comment to a committee of 26 additional scientists.

The 20 scientists who produced the study ranged from experts in entomology, molecular biology, genomics, crop biotechnology, law, sociology, and ecology, said Fred Gould, an entomologist from North Carolina State University, who chaired the committee.

"We had very different opinions and perspectives at the beginning of this process," he said during the Academies' public release of the report on Tuesday. Yet every member of the team signed off on the study's conclusions, he said.


GM traits on the market fall largely into two categories: insect resistance, in the form of plants that produce Bt toxins, and herbicide tolerance.

The study found that Bt technology has mostly been a bonus for the environment and agriculture. There is strong evidence that it has increased crop yields and lessened the use of synthetic insecticides in cotton and corn, all while boosting the biodiversity of insects in Bt fields.

The only downside to Bt technology the study uncovered was due to user problems -- in places where refuges were not implemented or used correctly, insect resistance has become a major problem, Gould said.

Herbicide tolerance's main benefit has been increased flexibility to farmers, the study concluded. The traits "sometimes contributed" to yield increases, but the widespread evolution of resistant weeds has become a major agricultural problem, Gould pointed out.

The scientists struggled to evaluate how herbicide-tolerant crops have affected herbicide use. The only available data is limited to pounds used per acre, which doesn't account for different rates of use and toxicity levels between chemicals, Gould said. "The data here is not meaningful," he said. "We need a more sophisticated look at what is changing in agrochemical usage."

Finally, GM technology has not significantly boosted crop yields, Gould said. "We hear a lot of claims that we need GE technology to feed the world," he said. "But with the advent of GE crops, we're not seeing increasing rates of yield increase. That's an important finding we need to focus on."


The study dug deep into the controversy over whether GM crops affect human health. The committee examined 200 studies on animal, livestock, and human health, as well as nutrient and chemical composition studies.

They also examined disease trends, such as the rates of cancer and chronic diseases around the world.

"We found no persuasive evidence of adverse health effects that could be directly attributed to the consumption of food derived from GE crops," Gould said. However, since we only have 20 years of experience eating GM crops, there are incremental changes -- both good and bad -- that can be missed and maybe need more time to manifest, Gould cautioned.

The social and economic impact of GM crops is complex and understudied, the study added. "There has been little or no investigation of the return on investment in genetic engineering versus alternative investment aimed at low external input technologies (LEIT), such as agro-ecological improvements," the scientists wrote.

The available data suggests that "existing GE crops have generally been useful to large-scale farmers of cotton, soybean, maize and canola," but smaller farmers require more institutional help to see the same benefits, they concluded.

Nor is GM technology likely to be a panacea for all agricultural systems' production problems. "GE crops alone are not able to address the complex challenges of productively on small-scale farms in food insecure places," Gould said.


The study recommended that the government approach the future regulation of new genetic engineering techniques differently, by focusing on the traits produced and less on the method used to produce them.

Regulators should consider the "novelty, potential hazard, and exposure" risks of a new trait, using a four-tiered approach. Foods, plants or animals that were developed and showed little to no difference to their counterparts on the market wouldn't require further testing. Those that did show differences or had the potential to produce new effects would require additional testing.

You can download the Academies report on GM crops here: http://bit.ly/…. You can find more details on the committee, their process, as well as details on the studies they examined, at the Academies' GM crops report website here: http://nas-sites.org/….

Emily Unglesbee can be reached at emily.unglesbee@dtn.com

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Emily Unglesbee