How Science Works: Learning From Controversy Over a Study Linking GM Corn to Tumors in Rats

In November of 2012, the journal "Food and Chemical Toxicology" published a paper by French scientist Gilles-Eric Séralini and his colleagues called "Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize."  The study was developed because Séralini and his team were interested in indications of toxicity found in the raw data of an earlier 90-day study done by Monsanto.  The results of Séralini's two year study showed as much as 5 times more liver and kidney disease, and 2 to 3 times more tumors in rats that had eaten Genetically Modified (GM) corn and that had drunk water containing Roundup. In August of 2013, the journal retracted the article after reviewing the study design and the data it was based upon.  Among the flaws they noted was that there were too few animals in the study, and the type of rat used, the Sprague Dawley, is prone to cancers and tumors.  Folks on both sides of the issue have cried foul, some for the publication of the article in the first place, and others for its retraction.  Both sides continue to present data and arguments to support what they believe to be the truth. And that's where this gets interesting, pointing out the importance of understanding the scientific process and how difficult it can be to get everything just right.  It also brings up the specter of profit and politics, two issues that are hard to remove from the daily lives of humans, leaving us with the question:  Who should we beli

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12 thoughts on “How Science Works: Learning From Controversy Over a Study Linking GM Corn to Tumors in Rats

  1. Thanks for getting this conversation started here and we look forward to your next installment. I’d like to guess that the “scientific protocol” that allowed Monsanto to pick which ten rats it wanted to report on was originally created by researchers who did not want to report the real truth of their findings. Sure, “they” will rattle off 25 reasons this “protocol” is OK and scientific but they are just trying to fool themselves as well as the rest of us. Just another example of how broken the system is. We will continue growing quality forage and avoid using herbicides and pesticides and share our methods with each other. Hopefully more and more people will do the same. Thanks.

    1. I didn’t do a good job when I wrote the sentences about Monsanto testing only 10 rats out of its group of 20 and I left the impression that they may have done something bad. I have since checked out the protocol (OECD 452) more fully. The protocol allowing researchers to run research that includes 20 animals in a group but to only have to do blood work on 10 of them was developed by the Organization of Economic Cooperation and Development. The purpose of this protocol, like all of the others, is to make sure that scientists follow proper procedures. Observations are done on all animals in the group, but blood work is only done on at least 10 males and 10 females from each group. The same rats are tested throughout the life of the study so researchers can’t just pick animals to get the results they want. Blood work is expensive, so doing it on only some of the animals saves money while still providing a study with statistical validity. All the animals are sacrificed at the end of the study and necropsied and information is gathered on all of them at that point.

      It’s unfortunate that this kind of controversy tends to reduce trust in scientists. Of course each scientist starts with a hypothesis, and maybe even has a preferred outcome. But my experience working with researchers has demonstrated that overall they are trustworthy, and the system they work within has enough checks and balances that those who cut corners are found out sooner rather than later.

      1. Thanks Kathy, for the clarification on the protocol and how it is carried out. You are fairly bringing out issues in a easy way to understand.


  2. The one thing missing in this debate is the confirmed fact that weeds are becoming resistant to glyphosate which was a given at the beginning which Monsanto knew. Chemicals are always going to be defeated by the natural world. And the geneticists at Monsanto ignored this.

  3. Ron,
    I do not believe Kathy is riding into the valley of death. She is explaining research methods and that I appreciate. The part I am glad she brought out was Dr. Huber used ten rats and Monsanto used 20 and cherry picked the 10 to use for the results. That is, in my thinking, unethical. I can make thinks look much better be picking results that fit what I want instead of going with what is found.

  4. Hi Kathy,

    Are you sure you want to open this can of worms on science? I’m sure you realize that this subject (science) is fraught with political and economic overtones that preclude changes being made about the “truthiness” of science. I’ve included a few links to articles that show that much of what is viewed as the truth (something that science is tasked with ferreting out) is nothing more than what a person has been lead to believe. I rarely believe anything that I read/hear/see in the mainstream media anymore – especially if there is any economic ramifications to the subject at all. Instead, I will research on my own to determine – as much as possible – what the facts are on the subject. I doubt most people have either the time nor the inclination to do so themselves; too much “backfire effect”!

    I think you’re riding into the “Valley of Death” on this subject.

    1. Well, having opened this can of worms a bit, and on a study that is very controversial, I agree that it’s very scary. In fact, I’m working hard on both understanding and explaining how statistics worked in this study and should work in general for the follow up article.

      The fact is that every single human being comes with bias of some sort. The purpose of the way we go about gathering information is “supposed” to give us the best shot possible at being as transparent, authentic and as truthful as possible. What I hope to do is help us all be more careful consumers of information, and to notice when biases are showing, whether it’s our own or someone else’s. I’d also like to promote more thoughtful dialogue, a little trust, some self-awareness, and a lot less name calling and insults. I believe that’s the path to better solutions to all the issues we face.

  5. Good article. I hate the fact that a new term “good science” is now being used and my definition of “good science” is a particular study or research providing information that agrees with someone or some groups point of view.

    Too often now, when we hear that “a scientific study concludes:” we just groan and discount the information.

  6. Kathy,
    When Monsanto used 20 rats and picked the ten to use for their results that would seem to be not only unethical but manipulating the results. If someone can cherry pick the results that is not true research in my thinking.

    I have always assumed there was a standard protocol to follow. Is the Monsanto research method allowable in the scientific community?

    This was a great article. Thanks for delving into the two research programs to bring out the differing methods. All the fighting going back and forth in the news is hard to understand without clarification.

    1. Hi Chip!
      I’ve been doing a lot of reading on this topic and have learned that there is a scientific protocol that allows for the testing of only 10 of the rats, making what Monsanto did perfectly fine. I’m not sure why, because I’m not a statistician which is what makes trying to write about this for the regular person, like me and you, so very hard.

      1. I’m glad to see the issues discussed, but would point out the following- 1)there are several statistical strategies for dealing with experimental evidence. Likewise numerous statisticians -and of course THEY do not speak with unanimity. 2)Following one “recognized” protocol carefully without deliberate cheating is important, if only so that others can evaluate your work. But suppose the chosen protocol was not entirely appropriate, and a different one gives a different answer? In any case, independent replication will be needed to sort these problems out.
        So what is a concerned individual to do?
        Well he/she can look at the evidence to the extent time permits, and make a TENTATIVE conclusion, subject to modification as new info- emerges. It saves time to defer to opinions of some experts ,whom one believes are better informed on the issue. Of course one’s opinion of any expert, or group thereof, can also change, especially as circumstances change and new info- emerges.
        ‘Twas ever thus -We all live with our beliefs and the knowledge that others disagree. These beliefs may be better informed by statistical analysis or indeed refuted (at least for the time being.) Daniel Kahnemann has a best seller– THINK FAST, THINK SLOW, that guides one thru to some realization of how often we deceive ourselves with or without statistical help.

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