“Cornflakes” (Séralini GMO study)


I understand how a person could be misled by the contents of an inaccurate TV news health segment or a Friend’s Facebook link. There are many demands on our time and society offers information in quickly-digested nuggets.

That’s part of the explanation for how long-discredited ideas can refuse to be extinguished. Even when an idea if publicly and repeatedly refuted, such an Andrew Wakefield’s vaccine-autism link, the claim can still find life in extremist circles. Another example still making the rounds is a study in the journal Food and Chemical Toxicology by molecular biologist Gilles-Eric Séralini. He concluded there was a clear link between consumption of genetically modified corn and cancer in rats.

If one only had time to a glance at the headline or to skim a few paragraphs from an article, a person might well believe this. Compounding the problem is that such stories aren’t always limited to unscientific sources like Joseph Mercola, Food Babe, and Modern Alternative Mama. The mainstream press can also be taken in, the result of both a race for readers and a scientific illiteracy among journalists that is a microcosm of the culture.

As to the specifics of Séralini’s study, he used 100 male and 100 female rats that were divided into groups. Some were fed various amounts of GMO corn, either zero, 11, 22, or 33 percent of their diet, with the rest of their food being standard lab rat fare. Another group was fed GMO corn plus had RoundUp added to their water. Séralini’s study was redacted after heavy criticism from regulatory agencies and scientific bodies, then republished by Environmental Sciences Europe even though no further review of it had been done.

When Séralini announced his findings, he sent a press release that contained an unusual stipulation. Reporters could only see the study if they agreed to not confer with other scientists until this embargo was lifted. This preempted any criticism and eliminated any chance of balanced treatment. This was a red flag with an especially strong scarlet hue. Someone doing genuine science seeks scrutiny, not security.

Augmenting this strange request were shouts of alarm from the researcher, which is almost always a giveaway that the findings are based on an agenda, not analysis. Séralini also released a book and documentary in conjunction with the press conference, two more suggestions that his motivations were name recognition and financial gain.

At the conference, Séralini also circulated photos of treated rats with large tumors. As Science Based Medicine pointed out, “It is standard practice in such studies to establish an endpoint, such as tumor number and size, at which point the animal will be euthanized.” SBM suspects Séralini allowed the tumors to grow in order “to have the intended effect on public opinion.”

Of course, one could self-promote, make a buck, and even treat animals unethically and still produce sound results. It would be a genetic fallacy to dismiss Séralini’s findings only because of the source and its sense of self-importance. Rather, we must look at the substance. And in so doing, we find several problems with the study. Dr. Steven Novella highlighted some of these, which include:

  1. The strain of rats that were used are highly susceptible to tumors and are likely to produce a false positive.
  2. There were only 20 rats in the control group, just one-fourth as many as were in exposed groups.
  3. Séralini’s data reported that “some” of the test groups had a higher tumor incidence. This cherry picking is usually done by biased sources scouring a report, not by an impartial researcher announcing it.
  4. Rats fed GM corn had the same negative effects as those who drank water with RoundUp added. It is very unlikely that two vastly different items like GM corn and RoundUp-laced water would have the same effect, and this is a strong indication of a false positive.
  5. There was no dose-response mentioned, a glaring omission when looking for a toxic effect. The dose–response describes the change in effect on an organism  caused by differing levels of exposure. In fact, there did not seem to be the connection Séralini asserted since rats that ate 11 percent GM corn developed more tumors than did those rats who were fed 33 percent GM corn.
  6. Researchers did not control for the amount of food consumed, a huge error since excess consumption of any food can increase tumors in this type of rat.

Because of such deficiencies, the article was redacted. Anti-GMO groups were quick to insist this was a cover-up, but peer review is about more than releasing information, it is also about further testing and investigation.

Novella also noted the issue with publishing preliminary research. Studies such as Séralini’s should only be meant to be an indicator of what further research may confirm. Most journalists won’t understand the difference between a preliminary research finding and a confirmatory one. Throw into the mix an emotional issue and an embargo to prevent balance and one arrives at this headline from a French newspaper: “Yes, GMOs are poison!”

But let’s examine what the newspaper would have found if it had dug deeper and performed real journalism. For starters, the Sprague-Dawley strain of rats Séralini used have a two-year lifespan and are always at high risk of cancer. Three out of four of these rats develop cancer under normal conditions, and this study covered the normal lifespan for this strain.

Second, even if Seralini’s findings resulted from sound research, they would be an outlier. Scientists at the University of Nottingham reviewed 24 long-term studies and found that none of them concluded that consuming GM foods put rats at increased risk. Anti-GMO groups highlighting Séralini’s result is what science journalist Andrew Revkin dubbed the “single-study syndrome,” where anomalous results are heralded if they fit the desired narrative.

The response from the anti-GMO, pro-Séralini camps consisted almost entirely of logical fallacies. Pop quiz time, critical thinkers. See if you can identify the fallacy used in these instances:

  1. Gmoseralini.com answered attacks on the methodology by writing, “Many of the charges that have been made against the Seralini study could be leveled against the studies that have been used to approve GM crops.”
  2. Seralini responded that 75 percent of the scientists who criticized his work were working on GMO patents or for Monsanto.
  3. From GM Watch: “The decision to retract the paper followed the journal’s hiring of a former Monsanto scientist to its staff.”

The following are from Holistic Health Living:

  1. “If we are to accept the argument that Séralini’s study does not provide substantial evidence that genetically modified food is dangerous, then we must also conclude that the short-term toxicity studies funded by the agriculture industry on GM foods cannot prove that they are safe.”
  2. “It would be nice to believe that Bill Nye and Neil deGrasse Tyson would never accept money from biotech to change their opinion. But both of them visited Monsanto’s headquarters, and both of them began singing GMO’s praises immediately after that. Thankfully, not every scientist is for sale.”
  3. “Many countries all over the world ban the cultivation of GMOs, and many countries mandate that GMOs be labeled.”
  4. “Health problems are rising along with increased GMO consumption.”


  1. Tu quoque, or the Appeal to Hypocrisy. Even if studies that arrived at pro-GM conclusions used faulty methods, this does nothing to advance the notion that Séralini used proper protocols.
  2. Ad hominem. Extra points if you identified as a specific type, the genetic fallacy. Séralini’s accusation is almost certainly untrue, but even if accurate, would be irrelevant to the legitimacy of the scientists’ criticisms.
  3. This is also an ad hominem and genetic fallacy since the focus is not on the challenge but on the person making it. This type of genetic fallacy is so common in the GMO debate that some skeptics put this subcategory its own subcategory, the Monsanto Shill Gambit. This is employed even when the person has no connection to the company.
  4. False Equivalence. Seralini’s faulty methods were outlined above and trying to throw all GM studies into the same category is nonsensical.
  5. Another ad hominem, specifically the Monsanto Shill Gambit again. Being unable to refute what Nye and Tyson have said about GMOs, they must resort to attacking the persons and fabricating a say-for-pay relationship.
  6. Ad populum. How many countries have done anything says nothing about whether it’s good or bad. An action’s legality is often unrelated to its fitness. Lunch counter protestors were criminals and SS members were enforcing the law. There are only two countries where women are a majority of the legislators, while nearly 40 percent of the nations punish blasphemy and extramarital relations. Applying the anti-GMO logic in these cases, we should only vote for men who endorse sodomy and apostasy legislation.
  7. Post hoc reasoning. Health problems are rising mostly because people are living long enough to experience them, thanks to scientific advances. Skeptical Raptor pointed out, “There are precious few ways to prevent cancer and avoiding GMOs is not one of them. “

Séralini was afforded the chance to publicly defend his research in a debate with University of Florida horticulturist Kevin Folta, but he withdrew two weeks before the event on the flimsy pretense that Folta was not a toxicologist. That is another example of committing a genetic fallacy, though mostly it’s just being a wuss.


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