The first animal feeding trial studying the lifetime effects of exposure to Roundup tolerant GM maize, and Roundup, the world's best-selling weedkiller, shows that levels currently considered safe can cause tumors and multiple organ damage and lead to premature death in laboratory rats, according to research published online by the scientific journal Food and Chemical Toxicology.
Researchers found that rats fed on a diet containing NK603 Roundup tolerant GM maize, or given water containing Roundup at levels permitted in drinking water and GM crops in the US, died earlier than rats fed on a standard diet. They suffered mammary tumors and severe liver and kidney damage.
The paper, "Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize" reports on a study conducted by a team of scientists led by molecular biologist and endocrinologist Professor Gilles-Eric Seralini, co-director of the Risk Quality and Sustainable Environment Unit at the University of Caen, France, who is an authority on studies into the health impact of GMO's and pesticides. It was supported by independent research organization, CRIIGEN.
Dr Michael Antoniou, molecular biologist at Kings College, London, and a member of the CRIIGEN scientific council, said: "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."
"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."
In the peer reviewed paper, the research team say they believe this is the first long-term animal feeding trial to examine the effects of Roundup, the world's most used herbicide, and a commercial Roundup tolerant GM maize. Researchers studied 10 groups, each containing 10 male and 10 female rats, over their normal lifetime - two years.
Three groups were given Roundup in their drinking water, at three different levels consistent with exposure through the food chain from crops sprayed with the weedkiller: the mid level corresponded to the maximum level permitted in the US in some GM feed; the lowest corresponded to contamination found in some tap waters. Three groups were fed diets which contained different proportions of NK603 - 11%, 22% and 33%. Three groups were given both Roundup and NK603 at the same three dosages. The final control group was fed an equivalent diet with no Roundup or NK603 but containing 33% of equivalent non-GM maize.
Researchers 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 tumours and pituitary disorders. Males suffered liver damage, developed kidney and skin tumors and experienced problems with their digestive system. The team also identified a "threshold effect" where even the lowest doses were associated with severe health problems.
The report states: "Similar degrees of pathological symptoms were noticed in this study to occur from the lowest to the highest doses suggesting a threshold effect. This corresponds to levels likely to arise from consumption or environmental exposure, such as either 11% GM maize in food, or 50ng/L of glyphosate in R-formulation [the lowest concentration of Roundup in the rats' drinking water] as can be found in some contaminated drinking tap waters, and which falls within authorized limits."
- Up to 50% of males and 70% of females died prematurely (before deathscould be put down to normal aging) compared with only 30% and 20% in the control group.
- Across all treatments and both sexes, researchers found treated rats developed 2-3 times more large tumors than the control group, defined as 17.5mm in females and 20mm in males.
- By the beginning of the 24(th) month 50%-80% of females in all treated groups had developed large tumors, with up to three per animal. Only 30% of the controls were affected.
- The tumors "were deleterious to health due to a very large size", making it difficult for the rats to breathe, causing problems with their digestion and resulting in hemorrhaging.
- The first large detectable tumors appeared after four and seven months in males and females respectively but only after 14 months in the female control group and 23 months in a control male. However, the majority of tumors were only detectable after 18 months.
Treated males suffered severe liver and kidney dysfunction. Liver congestions and necrosis were 2.5 to 5.5 times higher than in the control group. There were also 1.3 - 2.3 times more instances of "marked and severe" kidney disease.
The lowest dose tested in the study (50 nanograms per liter) is below safety limits for glyphosate in water and crops. EU legislation sets the Maximum Residual Level (MRL) in water at 0.1 mg/liter, 1 mg/kg in maize, and 20mg/kg in other animal feeds like soy, oats and barley. The US sets an MRL in some animal feed of 400mg/kg.
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.
The research also highlights the urgent need for more research into the long-term effects of all GM food crops, which are currently grown on 1.8% of the world's agricultural land. In the US, 70% of processed foods contain GM ingredients without GM labeling, and 85% of maize now grown in the U.S. is GM. In the UK and Europe, GM maize is not consumed directly by humans but it is widely included in animal feed. Hundreds of thousands of tons of GM maize are imported to the UK each year for use in the diets of chickens, pigs and dairy cows. Meat and dairy products from animals fed on GM are currently sold in British supermarkets without any requirement for GM labeling.
Patrick Holden, Founder and Director for the Sustainable Food Trust, said: "This research raises a number of serious issues and it is now essential that regulators examine the findings carefully and that other researchers replicate this study on a larger scale to see if the same results are obtained.
"Looking critically at all aspects of food production, be they intensive, low input, organic or GM crops, has become a priority given that we can no longer be sure that global food supplies will be capable of feeding the growing global population. GM crops hold out the promise of helping to meet the triple challenges of climate change, resource depletion and population increase, but if they have negative effects on health we need to recognise this as quickly as possible and apply our energies in other areas.
"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."
The researchers hypothesize that the reason why NK603 GM maize, NK603 sprayed with Roundup, and Roundup on its own, all produced very similar negative health outcomes, is that both the GM maize and the weedkiller Roundup "may cause hormonal disturbances in the same biochemical and physiological pathway."
Glyphosate, the active ingredient in the herbicide Roundup is a known endocrine disruptor, and previous research has shown that it can cause liver and kidney failure if consumed above maximum permitted residue levels. However, this is the first research that suggests that even very low levels, such as those found in drinking water, are harmful when consumed over an extended period.
The paper says: "The results of the study presented here clearly demonstrate that lower levels of complete agricultural glyphosate herbicide formulations, at concentrations well below officially set safety limits, induce severe hormone-dependent mammary, hepatic [liver] and kidney disturbances."
It suggests that overexpression of the GM "transgene" EPSPS, which makes NK603 tolerant to Roundup in the field, may disrupt biosynthetic pathways and cause similar problems. Most edible GM crops use EPSPS to make them tolerant to Roundup.
Prof Seralini's co-authors are Emilie Clair, Robin Mesnage, Steeve Gress, Nicolas Defarge, Manuela Malatesta, Didier Hennequin, and Joel Spiroux de Vendomois.
Copies of the research can be obtained on request from CRIIGEN www.criigen.org and from Food and Chemical Toxicology www.journals.elsevier.com/food-and-chemical-toxicology.
The European Food Safety Authority (EFSA) said it was aware of the paper and would make a statement in due course. EFSA monitors on an ongoing basis scientific developments in relation to its work. In this context EFSA will consider the paper’s relevance taking into account the available scientific evidence including recent studies assessing, over a sustained period of time, the potential toxicity of foods derived from GM crops.
