US Signoff of GMO Corn Defies Science

High Levels of Genetically Engineered Toxins and Glyphosate in GMO Corn Pose Serious Health Risks in Mexico

Comments submitted to USMCA tribunal show U.S. approval of GMO corn not based on science

Washington, DC – Friends of the Earth U.S. submitted a brief describing significant new science on health risks of genetically engineered corn, which the U.S. failed to consider as part of its trade dispute with Mexico. These comments were invited by the tribunal and submitted on March 13, and support Mexico’s extensive presentation of the science and rejection of the U.S.’ grossly inadequate safety assessments.

The brief was submitted to the dispute resolution tribunal set up under the U.S.-Mexico-Canada Free Trade Agreement (USMCA), charged with determining whether actions taken by Mexico to keep genetically engineered (GE or GMO) corn out of tortillas and other common corn-based foods violate provisions of the USMCA, as alleged by the U.S. 

The comments highlight that U.S. approval of GE corn is largely based on industry assertions, not science. Assessments of reproductive, developmental, neurological, metabolic, microbiome, or GI tract-related health risks have not been addressed in a meaningful way through the U.S. Food and Drug Administration (FDA) process or via any other process in the public or private sector. U.S. regulatory approval of GMO corn has rested on assertions from technology developers that foods derived from GMO crops are “substantially equivalent” in composition to non-GE foods, which recent findings show are not founded on science. 

“The U.S. government’s submission to the tribunal is seriously deficient. It lacks basic information about the toxins expressed in contemporary GMO corn varieties and their levels. The U.S. submission also ignores dozens of studies linking the insecticidal toxins and glyphosate residues found in GMO corn to adverse impacts on public health,” according to Dr. Kendra Klein, deputy director of science for Friends of the Earth and co-author of the FOE comments. 

“The U.S. government has not presented an ‘appropriate’ risk assessment to the tribunal as called for in the USMCA dispute because such an assessment has never been done in the U.S. or anywhere in the world,” said coauthor Dr. Charles Benbrook.

The comments show that, since the commercial introduction of GMO corn varieties in the 1990s, there has been an approximate four-fold increase in the number of toxins and pesticides used on the average hectare of GMO corn. Subsequently, the levels of genetically engineered insecticidal toxins found in GMO corn grain are 50-100 parts per million (ppm), up from 2-6 ppm – the average when the limited existing GMO corn food safety studies were carried out up to 30 years ago. These levels exceed maximum food tolerances for widely used corn insecticides by 40- to 2,000-fold. 

The consequences of simultaneous exposures to multiple genetically engineered toxins along with residues of glyphosate and other pesticides used in growing corn have not been evaluated — a massive scientific gap in the ability to accurately assess human health risks of GMO corn as it could be utilized in Mexico. What’s more, health risks would likely be amplified in Mexico, as corn is the caloric backbone of the food supply, accounting, on average, for 50% or more of the calories in the Mexican diet.

Importantly, the comments summarize scientific data showing human health risks associated with the multiple insecticidal toxins found in GMO corn. While much of the focus of the health harms of GMO corn rightfully center on glyphosate and other hazardous herbicides that the crops have been engineered to withstand, emerging evidence on these toxins is concerning. Data show the potential for risk of adverse impacts on the human microbiome and GI tract, risks of allergenicity stimulating an immune system response “as potent as that elicited by cholera toxin,” and presence of antibodies against Cry toxins in at least 8% of Americans, clear evidence that the toxin remains mostly intact after passing through the human GI tract. 

Finally, the comments summarize scientific evidence linking glyphosate-based herbicides to increased risk of blood cancers, including non-Hodgkin lymphoma and leukemia, metabolic syndrome, kidney and liver disease, preterm birth, neurodevelopmental problems, and disruption of the bacterial microbiome in humans and other mammals.

FOE calls on the U.S. to provide science addressing these concerns in its USMCA response. The tribunal is expected to issue its ruling on the dispute in the fall.

Expert Contact:
Dr. Charles Benbrook, [email protected], 208-290-8707

Communications Contact: Shaye Skiff, Friends of the Earth, [email protected] 

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