Genetically Modified Corn: Safe or Toxic?

article image
Among engineered food crops, genetically modified corn is one of the most commonly cultivated.

Pick up a box of cereal or other packaged food at the grocery store, and chances are you’re looking at a genetically modified product. The Center for Food Safety, a nonprofit organization that seeks sustainable alternatives to harmful methods of food production technologies, estimates that more than 70 percent of the processed foods in U.S. grocery stores contain some genetically modified ingredients — mostly corn or soy. But, in most cases, these modified foods have received only limited testing.

For example, take the three genetically modified corn varieties already being sold by Monsanto that are the subject of new analysis by French scientists. Two of the varieties have been genetically modified to contain unique proteins designed to kill insects that eat them, and the third variety was engineered to tolerate Roundup, Monsanto’s best-selling herbicide. Foods containing this “modified” corn are now being eaten by people all around the world, but the French researchers contend that Monsanto’s studies do not prove the corns are safe to consume.

Under current U.S. law, corporations are not required to make industry-conducted studies public. But, in this case, thanks to a lawsuit and the involvement of European governments and Greenpeace attorneys, these studies were released for independent analysis by scientists not being paid by Monsanto.

The researchers, affiliated with the Committee for Independent Research and Information on Genetic Engineering (an independent, nonprofit association dedicated to studying the impacts of genetically modified organisms), published their detailed critique of the Monsanto studies in the International Journal of Biological Sciences (2009; 5:706-726). They concluded that the data — which Monsanto claimed proved the corn varieties were safe to eat — actually suggest potential kidney and liver problems resulting from consumption of all three modified corn varieties, as well as negative effects in the heart, adrenal glands, and spleen. The findings confirm a 2007 report from the same researchers on a single variety of modified corn.

An Apple Is an Apple Is a Genetically Modified Apple?

The new report also concludes that the Monsanto rat-feeding studies were so small and so brief that they clearly lack sufficient statistical power to prove the corn varieties are safe. So, why did governments grant permission to farmers to grow this genetically modified corn? Back in 1992, the industry persuaded the Food and Drug Administration (FDA) to rule that their crops are “substantially equivalent” to traditionally bred crops. This assumption — that genetically modified foods pose no particular risk — has led to our current system of weak regulatory oversight.

According to the nonprofit Pew Initiative on Food and Biotechnology, a project designed to facilitate dialogue about the pros and cons of genetic modification, “No single statute and no single federal agency govern the regulation of agricultural biotechnology products.” And, compared with the battery of tests demanded of chemical pesticides (evaluation of chronic exposure, carcinogenicity, etc.), the testing requirements for genetically altered crops amount to little more than a polite suggestion.

“The corporations can pretty much submit whatever they want to the FDA,” says Doug Gurian-Sherman, senior scientist at the nonprofit Union of Concerned Scientists. “Some have done animal testing, some have not. The United States does not require more than acute toxicity tests where one high dose is fed to the animals once. Even in Europe, where standards are higher, tests of only 90 days are the longest that are required, which is inadequate.”

While the FDA is charged with ensuring finished products containing the modified proteins are safe to eat, the Environmental Protection Agency regulates the pesticidal protein engineered into the corns. The agency can grant exemptions to even a minimal request for testing, which they did for two of these corn varieties — varieties that produce their own pesticides and that show signs of toxicity in the new feeding studies. The new study from France concludes that the public is consuming modified corn varieties which “contain novel pesticide residues” that may pose grave health risks.

“Roundup residues present in one genetically modified corn are much higher than those found to cause toxicity in human embryonic cells and endocrine disruption,” says Gilles-Eric Seralini, one of the study’s researchers. To learn more, read Roundup Weed Killer Kills More Than Weeds.

Confidential Science

In allowing industry to drive the regulation of the technology from which it profits, we are now faced with a reality in which never-before-consumed foods are considered innocent until proven guilty. The burden of proof has been dumped on a scientific community that has to beg and litigate to gain access to what the genetic modification giants call “trade secrets.”

The only solution to this situation is for scientists who work in this field and concerned citizens to demand that the government stop allowing corporate gene giants to have their way. We need laws that require corporations to make their studies public and provide seeds to independent scientists. And, we need laws that require the labeling of foods with genetically modified ingredients, so consumers can make informed choices.

You can find contact information for your congressional representatives by entering your zip code at Let them know that a change is in order.

Need Help? Call 1-800-234-3368