Scientific Study Finds Long-Term Health Impacts from GM Corn and Herbicide

A French  scientific study released this week asserts that laboratory rats fed Monsanto’s genetically modified (GM) corn or low levels of Roundup herbicide for two years developed tumors and suffered damage to multiple organs. The rats in the test group also experienced significantly higher mortality rate than the control group.

The study has also been sharply criticized by some members of the scientific community.

The lifetime study followed the long-term progress of three experimental groups of rats: one fed with NK603 genetically modified Roundup Ready corn, one fed the corn treated with ordinary levels of the glyphosate-based herbicide, and one that was fed water contaminated with Roundup. Each group was paired with a control group. The amounts of herbicide added were calculated to correspond proportionally to what a typical human eating these foods would ingest.

The rats fed the test diet developed mammary tumors, kidney and liver damage, as early as four months into the study for males, and seven months in, for the females. The control groups developed similar symptoms, but not until much later, 23 months and 14 months for the males and females, respectively

“This research shows an extraordinary number of tumors developing earlier and more aggressively - particularly in female animals. I am shocked by the extreme negative health impacts,” said Dr Michael Antoniou, molecular biologist at King’s College London, and a member of CRIIGEN, the genetic engineering watchdog group that supported the research.

Mortality was also higher. Researchers claim that 50 and 70 percent of the males and females died in the experimental group, as opposed to 30 and 20 percent in the control group.

GMO crops are generally approved on the basis of a 90-day feeding study. These researchers, led by Gilles-Eric Séralini at the University of Caen, felt that there was a need for a longer study to help understand the lifetime effects of these chemicals. Typical life expectancy for rats is two years.

Monsanto spokesman Thomas Helscher promised that the company would review the study thoroughly, despite the fact that, "Numerous peer-reviewed scientific studies performed on biotech crops to date, including more than a hundred feeding studies, have continuously confirmed their safety, as reflected in the respective safety assessments by regulatory authorities around the world."

The researchers concluded that these health impacts resulted from the transgenic traits in the corn and the endocrine disrupters in the herbicide. Endocrine disrupters are particularly dangerous for children as they adversely impact developing nervous and reproductive systems. A previous German study found that exposure to glyphosate damaged or killed testicular cells in rats within 48 hours of exposure at concentrations as low as 1 ppm. Researchers have found concentrations as high as 14 ppm in human urine, which suggests that an alarming amount of this herbicide is finding its way into food and water supplies. The EPA’s safe limit is 0.7 ppm.

Experts pointed out concerns with the study and were therefore reluctant to jump to conclusions. Tom Sanders, head of the nutritional sciences research division at King's College London was bothered by the fact that the details of the rats’ diets and growth rates were not disclosed. He called the statistical methods unconventional, suggesting that, “the authors have gone on a statistical fishing trip.”

Cambridge University statistician David Spiegelhalter called the methods, statistics and reporting of results all below standard. He pointed out that the study's untreated control groups comprised only 10 rats of each sex, most of which also got tumors.

Mark Tester, a research professor at the University of Adelaide, wonders why no previous studies have turned up similar concerns. "If the effects are as big as purported, and if the work really is relevant to humans, why aren't the North Americans dropping like flies? GM has been in the food chain for over a decade over there - and longevity continues to increase inexorably.”

That might seem to be a fair enough point at first blush, but given the growing rates of cancer, diabetes, obesity and other illnesses whose ultimate sources are yet to be determined, it is far from a definitive argument.

Of course, there have been other studies showing significant health concerns from GM foods. Jeffrey Smith’s book Seeds of Deception is filled with them. But they have all been debunked, suppressed, ignored by the media, or had their authors back down when confronted by the companies’ strong-arm tactics.

With so much at stake, and with vehement experts on both sides of the argument over whether GM foods or safe or not, it is difficult to find solid ground here. But given the potential risks as compared with the limited benefits to anyone other than the companies and their beneficiaries, it would seem prudent to at least require that foods containing these ingredients should be labeled accordingly, which is exactly what the people of California intend to do, come November with Proposition 37.

Across the Atlantic, they are taking this issue far more seriously. Growing GM crops is already banned in France. As the result of this study, the French health, environment and farm ministries are asking “the European authorities to take all necessary measures to protect human and animal health, measures that could go as far as an emergency suspension of imports of NK603 maize in the [entire] European Union.”

Even if scientists are deadlocked on the issue, the fact is the consequences of the pro-GMO camp being wrong are far higher than if the crops turn out to be safe after more extensive study. But the precautionary principle does suggest further study.

So does study co-author Michael Antoniou. He emphasizes the “need to test all GM crops in two-year lifelong studies.” He also feels that “this data is strong enough to withdraw the marketing approval for this variety of GM maize temporarily, until this study is followed up and repeated with larger number of animals to get the full statistical power that we want.”

[Image credit: Novartis AG: Flickr Creative Commons]

RP Siegel, PE, is an inventor, consultant and author. He co-wrote the eco-thriller Vapor Trails, the first in a series covering the human side of various sustainability issues including energy, food, and water in an exciting and entertaining format. Now available on Kindle.

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