Foes of modified corn find support in studyRats fed either genetically engineered corn or the herbicide Roundup had an increased risk of developing tumors, suffering organ damage and dying prematurely, according to a new study that was immediately swept up into the furor surrounding crop biotechnology when it was released Wednesday.
By: Andrew Pollack, New York Times News Service
Rats fed either genetically engineered corn or the herbicide Roundup had an increased risk of developing tumors, suffering organ damage and dying prematurely, according to a new study that was immediately swept up into the furor surrounding crop biotechnology when it was released Wednesday.
The study, conducted by a prominent opponent of genetically engineered crops, was immediately criticized by some other scientists, who said the methods were flawed and that other research had not found similar problems.
But in California, proponents of a ballot measure that would require genetically modified foods to be labeled immediately seized on the study as support for their cause. The French government ordered a review of the findings, saying they could possibly result in the suspension of European imports of that type of corn.
The study, which is being published in the peer-reviewed journal Food and Chemical Toxicology, was led by Gilles-Eric Seralini at the University of Caen in France. He is also a leader of the Committee for Independent Research and Information on Genetic Engineering, which sponsored the research.
The study followed 200 rats for two years, essentially their entire lives, far longer than the typical 90-day feeding studies used to win regulatory approval of genetically engineered crops in some countries. While there have been some other long-term studies, none has involved as many animals or as many detailed measurements.
“The results were really alarming,” Seralini said in a telephone news conference conducted by an organization in Britain opposed to genetically modified crops.
He said that the tumors did not develop until well after 90 days, meaning they might have been missed by shorter studies.
The rats in the study were split into 10 groups, each containing 10 male and 10 female rats. Six of the groups were fed different amounts of a corn developed by Monsanto to be resistant to the herbicide Roundup. In some cases the corn had been sprayed in the field with Roundup.
Three other groups were given different doses of Roundup in their drinking water, with the lowest dose corresponding to what might be found in U.S. tap water, the authors said.
The 10th group, the control, was fed nonengineered corn and plain water.
The study found that in groups that ate the engineered corn, up to 50 percent of the males and 70 percent of the females died before they would have from normal aging, compared with 30 percent of the males and 20 percent of the females in the control group.
Some 50 to 80 percent of the female rats developed tumors compared with only 30 percent of the controls. And there were several times as many cases of liver and kidney injury in the exposed rats.
Numerous scientists, however, criticized the study’s methods and the ideological manner in which it was being presented.
“This is not an innocent scientific publication,” Bruce M. Chassy, professor emeritus of food science at the University of Illinois, said in an email. “It is a well-planned and cleverly orchestrated media event.”
Some critics pointed out that the new findings contradicted other studies. One review of long-term studies, published earlier this year, concluded that those studies did not present evidence of health hazards.
Chassy said that people and livestock had been eating genetically modified grains for years without evidence of the high death rates and tumors in the study.
“Curious that no increase in tumor incidence has been reported in animals eating large amounts of such grains,” he said.
David Spiegelhalter, a professor at the University of Cambridge specializing in the public perception of risk, said the numbers of animals in each group was too low to draw firm conclusions.
Another red flag for some scientists was that higher doses of the crop or the herbicide did not cause more harm than lower doses, which would have been expected if the crop or the chemical were truly harmful.
Seralini’s work has been questioned before. A review of one of his studies by European authorities concluded that his statistical methods “led to misleading results” and that his study had not raised new issues about the safety of the crop.
Monsanto, in a statement, said it would review the study, but that other studies had confirmed the safety of its crops.