A provocative new study is adding fuel to the debate over the potential health effects of genetically modified food. European researchers say rats fed a diet of genetically modified corn developed large tumors and multiple organ damage that led to premature death.
The study, published in the journal Food and Chemical Toxicology, is believed to be the first peer-reviewed, long-term animal study of a genetically modified food. It was funded by the Committee for Research and Independent Investigation on Genetic Engineering (CRIIGEN), which lobbies against pesticides and genetically modified food.
Researchers fed the rats with corn genetically modified (GM) to be resistant to Roundup, a widely used herbicide, or gave them water containing the weed killer at levels permitted in drinking water in the United States. The rats suffered mammary tumors, severe liver and kidney damage, and died at an earlier age than rats fed a standard diet.
“This is the most thorough research ever published into the health effects of GM food crops and the herbicide Roundup on rats. It 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 Michael Antoniou, molecular biologist at London’s Kings College and a member of the CRIIGEN scientific council.
“The rat has long been used as a surrogate for human toxicity. All new pharmaceutical, agricultural and household substances are, prior to their approval, tested on rats. This is as good an indicator as we can expect that the consumption of GM maize and the herbicide Roundup, impacts seriously on human health,” said Antoniou.
Researchers studied 10 groups of rats, each containing 10 males and 10 females, over the course of two years, their normal lifetime. They were given different levels of Roundup in their drinking water and different amounts of NK603 maize, the corn genetically modified to be resistant to Roundup.
They found that NK603 and Roundup both caused similar damage to the rats’ health, whether they were consumed on their own or together. Females developed fatal mammary tumors and pituitary disorders. Males suffered liver and kidney damage, skin tumors and developed problems with their digestive system. Researchers say even the lowest doses were associated with health problems. The lowest dose was below safety levels for glyphosate, the active ingredient in Roundup.
Up to 50% of the males and 70% of the females died prematurely. After two years, over half the females had developed large tumors.
“The research findings raise serious questions about the current regulatory process for licensing industrial chemicals, pesticides and other novel crops. The scientists observe that GM crops have been approved safe for consumption on the basis of 90-day animal feeding trials. They also point out that only Roundup’s active principle, glyphosate, has been tested rather than the commercial product, which includes ingredients that enable the glyphosate to penetrate plants more efficiently,” CRIIGEN said in a statement.
Seventy percent of processed foods sold in the U.S. and 85% of the corn grown in the U.S. is genetically modified, according to CRIIGEN.
“On the basis of this study, we have to conclude that there is now a serious question mark over the safety of at least one GM crop. This suggests that all currently licensed GM crops should be re-evaluated and that in future safety studies in laboratory animals must be conducted over significantly longer periods of time that are equivalent to the animals’ normal life span not simply their adolescence,” said Patrick Holden, founder of the Sustainable Food Trust, which lobbies for food safety.
Genetically modified foods are unpopular in Europe, but are widely available and often unlabeled in the United States. Monsanto, which makes Roundup, first introduced a soybean genetically altered to tolerate the weed killer in 1996. Monsanto said it would need time to review the CRIIGEN study.
“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,” said Monsanto spokesman Thomas Helscher.
Some experts raised questions about the CRIIGEN study.
“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,” said Mark Tester, a research professor at the Australian Centre for Plant Functional Genomics at the University of Adelaide, in an emailed statement to Reuters.
In California, supporters of Proposition 37 moved quickly to call attention to the study. Prop 37 would require that all genetically modified food sold in the state be labeled.
“The results of this study are worrying. They underscore the importance of giving California families the right to know whether our food is genetically engineered, and to decide for ourselves whether we want to gamble with our health by eating GMO foods that have not been adequately studied and have not been proven safe,” said Gary Ruskin, manager of the Yes on Proposition 37 California Right to Know campaign.