French experts question GMO cancer study

French officials and experts have added their voices to the chorus of criticism over a recent study linking genetically modified corn to tumors in experimental rats.

The French national food safety agency joined six scientific academies in concluding the study was too badly done to support its conclusions.

The debate comes as voters in the US state of California consider whether to require labels on all foods with ingredients from genetically modified organisms, or GMOs.

Disturbing images

The study in the journal Food and Chemical Toxicology included shocking photos of rats which researchers say grew giant tumors after eating GMO corn for two years.

Study author Gilles-Eric Seralini at the University of Caen says his findings show regulations on the crop are not good enough.

"GM foods have been evaluated in an extremely poor and lax way with much less analysis than we have done," Seralini says.

Eighty percent of the packaged foods on US supermarket shelves contain GMO ingredients, according to the Grocery Manufacturers Association.

California advocates of a law requiring those ingredients to be identified on food labels have used the French study to bolster their argument.

The “Yes on 37” campaign, backing mandatory GMO labeling in this November’s statewide voter referendum, held a press conference with Seralini to announce the results of his research.

'Numerous problems'

However, other scientists immediately found problems with the study, including geneticist Alan McHughen at the University of California at Riverside, an expert with the prestigious U.S. National Academy of Sciences.

“First of all, the authors of the study used a line of rats that was genetically predisposed to form tumors in the first place," McHughen says. "So right off the bat the whole study was suspect.”

The European Food Safety Authority also found numerous problems with the French study, from not enough control rats to substandard analytical methods. And the French science academies said the release of the study, which coincided with the release of a book and a film highlighting the work, raised ethical problems.

At the University of California at Davis, toxicologist Alison van Eenennaam questioned the researchers’ motives.

“I think it was a cynical ploy to exploit the scientific process to create fear in the minds of consumers,” she says.

Long-term tests?

Even opponents of genetic engineering agree the study was flawed. But they believe more long-term studies should be done.

“There should be required safety assessments before these crops are put on the market," says Michael Hansen, with the advocacy group Consumers Union. "That is not what happens in the United States.”

The French food safety authority called for more publicly funded research covering the entire life span of experimental animals.

US tests

The US Food and Drug Administration normally reviews voluntary safety assessments that companies submit for new GM crops. They typically include a 90-day rat-feeding test for toxicity.

That is the international standard. And the longer studies that have been done have not shown major problems, says UC Davis’s Alison van Eenennaam.

“The science doesn’t show there’s any additional data that wouldn’t already be caught at these 90-day studies,” she says.

Regulators OK GMOs

Regulators in the U.S. and Europe, as well as the U.N.’s World Health Organization and Food and Agriculture Organization, have concluded that genetically modified products on the shelves today are no more dangerous than products made the usual way, according to UC Riverside’s Alan McHughen.

“All of those, I think, give us the body of scientific evidence to state with a certain degree of confidence that yes, these products are as safe as other products on the market,” McHughen says.

Public confidence in this reassurance will be put to the test in the California referendum November 6, when state voters decide if GM foods should carry a special label.