Many Scientists Smell a Rat in French GMO Rat Study

A recent French study that purports to show a link between the consumption of genetically modified corn and a variety of ailments, including cancer, was just the tasty morsel that critics of genetically modified foods (GMOs) hungered for.  For many scientists, however, the study proved to be a source of indigestion. 

To be sure, GMOs are a hot button issue, especially with the looming prospect of California’s Proposition 37 that would require labeling of foods that have any component derived from genetically modified crops.  Emotions are already boiling over with members of activist groups, such as the ridiculously named “Genetic Crimes Unit,” screaming about genetic crimes against humanity as they don bio-hazmat suits to block shipments of Monsanto’s transgenic seeds.  They are also fond of displaying a giant “fish-corn”, implying that biotechnology companies are engaged in melding fish genes with corn genes.  Absurd. 

Mike Adams, the self-appointed “Health Ranger,” who routinely floods the Internet with stupefying diatribe on his “NaturalNews” website goes even further.  “I predict, but DO NOT CONDONE,” he says, “scientists who conduct research for Monsanto being threatened, intimidated and even physically attacked….an inevitable reaction to the unfathomable evil being committed by the GMO industry and its co-conspirators.”  Seems to me Adams is the evil one by implanting such ideas.  There are indeed some very legitimate issues to be addressed about genetic modification, but proper intellectual discourse has no room for such inflammatory tirades from untethered scientific nobodies.

Mistrust and confusion are often the result of a lack of understanding of the science involved.  So let’s take a look at what the controversy, at least as it pertains to the French study, is all about.  The researchers aimed to explore the effects of consuming corn that is genetically modified to resist “Roundup,” Monsanto’s popular herbicide.  Such “Roundup-resistant” corn is unharmed when sprayed with glyphosate, the active ingredient in Roundup, while weeds wilt.  This is of great advantage to growers because the technology makes weed control easier and more effective, fields require less tillage while yields and profits increase.  Before the introduction of glyphosate-resistant crops it was common to use as many as ten different herbicides, most of which had worse toxicological profiles than glyphosate.

Glyphosate was discovered back in 1970 by John Franz while working at Monsanto.  It works by inhibiting the plant enzyme EPSPS (5-enolpyruvylshikimate-3-phosphate synthase, if you must know) which is critical for the synthesis of three essential amino acids, tryptophan, tyrosine and phenylalanine.  These in turn are needed by the plant for protein synthesis as well as for conversion into a variety of compounds such as phenolics, tannins and lignins that are essential for plant life.  If EPSPS is inactivated, the plant withers and dies. 

Some microbes also rely on EPSPS for protein synthesis, and in 1983 researchers discovered that a strain of the common soil bacterium, Agrobacterium tumefaciens is highly tolerant to glyphosate because its EPSPS is less sensitive to inhibition by this herbicide than the version found in plants.  By 1986 the bacterial gene that codes for this enzyme was isolated and soon inserted into the genome of soybeans, corn, canola, alfalfa and sugar beets, allowing fields to be sprayed with Roundup for elimination of weeds without affecting the crops.  As a result, genetic modification has become the most rapidly adopted technology in the history of agriculture.  But it has also unleashed a cavalcade of criticism. 

There are concerns about seed companies establishing strict criteria for the use of their seeds by farmers, there are questions about weeds developing resistance and of course worries about safety.  While the majority of scientists familiar with the technology were satisfied that the concerns had been properly addressed, there were some who thought that regulatory agencies had jumped the gun.  One of these was Gilles-Eric Seralini, lead author of the current controversial study.

Seralini has written several anti-GMO books and has published other papers that claim to show adverse effects attributed to GMOs.  He is a vocal anti-GMO activist and has already been chastised by the European Food Safety Association (EFSA) for improper analysis of data.  His present study involved feeding various combinations of genetically modified corn and glyphosate to rats over their lifetime and concluded that the experimental rats had a shorter life expectancy, developed more tumours and had more liver and kidney problems than a control group.  There were horrific pictures of rats with giant tumours that were quickly snapped up by a media not adverse to sensationalism.

The response from the scientific community was immediate and harsh.  The control group was way too small, there was no disclosure of control rats with tumours, data were improperly interpreted, there was no dose-response relationship and the strain of rat used was genetically susceptible to tumours.  Particularly bothersome was the fact that the research group refused to provide advance copies of their work to reporters unless they signed agreements not to consult other experts.  This flies in the face of proper scientific practice.  Furthermore, Seralini has now stated that he will not allow scientists from EFSA to verify his results because they are the ones who approved GMOs in the first place and therefore cannot be trusted.  That sort of behaviour, to be kind to the man, is bizarre.

The true crux of the matter is that this study has virtually no relevance to people because the diet the rats were fed is not even remotely reflective of the human consumption of foods that have components derived from genetically modified corn.  The media randomly bandies about the statement that most of the food we eat contains genetically modified ingredients.  Technically that is true if you consider, for example, high-fructose corn syrup (HFCS) derived from GM corn to be a genetically modified ingredient.  The fact is that there is no vestige of genetic modification in this product.  It is indistinguishable from any other HFCS.  Contrary to popular belief, there are no genetically modified strawberries, tomatoes, potatoes, wheat, rice or fruits on the market with the exception of Hawaiian papaya that has been engineered to protect it against a fungus thereby saving a whole industry.

Although GM sweet corn is grown in a few places, by far the majority of GM corn goes into animal feed.  Our consumption of GM ingredients is limited to some food additives and oils that are derived from GM corn, soy or canola.  This has little relation to feeding GM corn to rats as the major component of their diet.  Furthermore, millions and millions of cattle and poultry have now been raised on GM corn over many generations without any health effects being noted on them or their consumers.

What we need in the GMO controversy is reasoned argument, not scandalous headlines.  “Study: GMOs may shorten your life” shrieks a report on Seralini’s paper by Rodale press.  The study shows nothing of the kind.  What it does show is the readiness of some GMO opponents to jump on a questionable study to promote their fear-mongering agenda.

Print | posted on Thursday, October 04, 2012 10:08 PM

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