Science, Tech & Environment

French study raises questions about health effects of genetically modified corn


Roughly 80 percent of the corn grown in the United States is genetically modified. (Photo by Victor Bayon.)

Scientists from France recently published a study that shows massive tumors and early deaths for rats that ate genetically modified Roundup Ready corn.

Player utilities

Listen to the Story.

Roughly 80 percent of the corn grown here in the United States is genetically modified — nearly three quarters of it is Roundup Ready, genetically altered to tolerate the Monsanto herbicide Roundup.

The research out of France was looking at the long-term health of rats fed a steady diet of Roundup Ready corn.

Some 200 rats were followed over four years. One group was fed Roundup Ready corn that had been sprayed with Roundup. A second group was fed genetically modified corn not sprayed while a third group ate no genetically modified corn, but drank water that had traces of Roundup in it at levels considered safe by the government. A fourth group of rats was a control — they ate no Roundup corn or water.

The study's author, Gilles-Eric Seralini, said they found tumors in as little as four months.

"After one year there were high increases of the number of tumors," he said, "up to almost every rat having two or three tumors for the female rats (fed) the lowest doses of Roundup."

Seralini says the rats that ate the genetically modified corn, whether or not it was spiked with Roundup, or drank the Roundup-laced water, got tumors earlier than rats in the control group. They also died much earlier: 50 percent of male rats died early, compared to 30 percent not fed the Roundup corn. And 70 percent of females died early compared to just 20% for the rats not fed the Roundup corn.

The rats all died of various cancers.

Roundup Ready corn has been on the market in the U.S. for years, and has been approved by the FDA. In a statement, Monsanto blasted the study's findings.

"This study does not meet minimum acceptable standards for this type of scientific research, the findings are not supported by the data presented, and the conclusions are not relevant for the purpose of safety assessment," the company wrote.

Specifically, Monsanto says the study size of 200 rats is too small. And they say that the rats used in the French study are pre-disposed to tumors and cancer. But these rats are exactly the same type as Monsanto uses in its own studies.

The U.S. Food and Drug Administration says they are still reviewing the study and wouldn't comment on whether this would lead to any changes in the United States. Michael Hansen, a senior scientist at Consumers' Union, says genetically engineered foods are treated like any other plant that has been bred for certain traits.

"The FDA has actually never made a conclusion about the safety of any of these engineered foods that are on the market," he said.

Hansen says the study needs to be repeated, and with a larger group of rats, to see if it gets similar results.

"Why can’t countries get together and do a definitive study that everybody agrees is a proper sample size? Put up the money and see that it’s properly done," he added.

The French study cost some $3 million.