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The Science on GMOs Isn't Settled — Here's Why

One of the most common questions we see on our social media channels is, "Where is the science that GMOs […]

The Science on GMOs Isn't Settled — Here's Why

One of the most common questions we see on our social media channels is, "Where is the science that GMOs […]

One of the most common questions we see on our social media channels is, "Where is the science that GMOs are bad for you?" 

There is a short answer and a long one. The short answer is dozens of studies show uncertain or adverse impacts from GMOs (you can scroll down to the end of this article to find a list of some of them). However, for every independent study showing uncertain or negative impacts from GMOs, many more industry-funded studies show no concerns at all — and the disparity between independent and industry-funded research is where the real issue lies.

Research that indicates potential negative impacts of GMOs tends to face virulent, bewildering and sometimes nonsensical criticism. The studies are denied by pretense rather than being challenged on substance. The researchers and the journals behind them face intimidation campaigns and professional attacks. In short, such studies are met with a "kill the messenger" response that sows confusion and mistrust while leaving crucial questions about GMOs unanswered.

Until scientific methods are applied evenly on both sides of the debate, "Where's the science?" is the wrong question. We believe the right question is: Why are comparable scientific studies with opposing findings treated so differently? 

The Pusztai paper

Shortly after GMOs entered the supply chain in the 1990s, researchers at the University of Aberdeen in Scotland conducted an animal feeding study to explore GMO safety. After feeding genetically modified potatoes to rats, they observed damage to the animals' intestines and immune systems. 

Before the study was published, one of the lead researchers, Dr. Árpád Pusztai, was interviewed about the study's findings. He modestly described the study's conclusions, then added, "If I had the choice I would certainly not eat [GMO potatoes]." The interview attracted attention, raising the study's profile. An error in a press release, though not in the research itself, was repeated in the media and sparked confusion and concern. Dr. Pusztai's attempts to correct the mistake were misconstrued as an admission of misconduct and he was fired from his research position. 

The scientific community was divided on the validity of the research. Several prominent scientists came to Pusztai's defense, while a committee of the Royal Society of London dismissed the study as poorly executed and designed. It's crucial to note that according to a 2015 analysis of the affair, none of the 900+ media articles written about the Pusztai paper offered "conclusive evidence of why his experiment was allegedly deficient." Ultimately, five of the six independent reviewers for The Lancet, the most distinguished medical journal in the world, supported the study's findings and recommended publication.

The study had been planned, conducted and reviewed according to best practices, and consistent with Dr. Pusztai's previous work. His exasperation at the study's treatment was palpable: "Supposedly in my previous 270 papers, some 40 of them with the same design and methodology, I was scientifically alright, but then suddenly I had a mental breakdown." 

The Séralini study

Another high-profile scandal is known as the Séralini study. In 2012, Gilles-Éric Séralini, a professor of molecular biology at the University of Normandy, France, led a toxicity study on genetically modified "Roundup Ready" corn and the glyphosate-based herbicide, Roundup, that is commonly applied to it. The study found that rats who consumed Roundup at concentrations below established safety limits experienced "severe hormone-dependent mammary, hepatic and kidney disturbances’' and a high incidence of tumors. 

Soon after the paper was published in the journal Food and Chemical Toxicology (FCT), criticism poured in. Researcher Sheldon Krimsky compiled an inventory of the main points in his paper, An Illusory Consensus Behind GMO Health Assessment:

"Séralini was criticized for not following OECD guidelines in doing such experiments, but as he pointed out, there are no such guidelines for in vivo studies of GMO toxicity. He was criticized for using too few animals. His response was that ten animals in each sex group was recommended by OECD in 1981. People criticized him because he did not use the protocols for a carcinogen study. He responded that his study was not a carcinogen study but rather a long-term, full toxicological study. Nevertheless, he was required to report any lesions or tumors, which he did."

FCT released an editorial outlining its publication standards and singling out the Séralini study as having met all of them. While FTC confirmed that Séralini's data was not incorrect and there was no misconduct, fraud or intentional misrepresentation, the journal later retracted the study without the authors' consent — a puzzling decision as it met all the standards for publication and none of the standards for retraction. The Séralini study was republished in 2014 in Environmental Sciences Europe and the controversy remains intact.

Studying the studies: A curiosity in double standards

For science to expand our understanding, research must be independent and rigorous. It must be executed and assessed in good faith and adhere to standard protocols. 

Thankfully, there is a growing body of scholarship on independent and industry-led research, comparing studies' design, execution and reception. These papers help to untangle some very dense subject matter. In Sheldon Krimsky’s paper, he analyzes the reception and legacy of GMO research. Krimsky found a general trend of friendliness and receptivity toward industry-led research, even studies based on the same methodology as the independent studies that faced severe criticism. When differences between test subjects are found in industry-led studies, they are more readily dismissed as irrelevant. For example, in her paper Retraction by Corruption: The 2012 Séralini Paper, Eva Novotny notes that a 2004 study funded by Monsanto and similar in design to the Séralini study, found disturbing health signs that were dismissed in the published paper.

Holding studies to different standards because of their results is a profound failure of the scientific method. Such biased reception creates a chilling effect, inhibits further research and leaves vital questions unanswered. The ongoing confusion erodes public trust and reduces transparency in the food system. We need further long-term studies on GMOs. 

In a recent interview with Food Sleuth Radio, Non-GMO Project executive director Megan Westgate characterized the biotechnology industry as utterly lacking in curiosity and ongoing inquiry. "The whole industry that calls itself scientific is based on upholding a narrative that supports continued profits. It is not scientific. It is not curious. And it is not going to serve us in the very critical moment we find ourselves in."

You don't have to take our word for it. 

The following studies are listed in Sheldon Krimsky's paper An Illusory Consensus Behind GMO Health Assessment as indicating uncertain or adverse impacts from GMO consumption or exposure to the pesticides that accompany GMOs. We encourage curiosity and further reading on the studies and their reception by the biotechnology industry.

  1. Fine Structure Changes in the Ileum of Mice Fed on Endotoxin-treated Potatoes and Transgenic Potatoes, 1998
  2. Effects of diets containing Genetically Modified Potatoes Expressing Galanthus nivalis Lectin on Rat Small Intestine, 1999
  3. Trip-trophic Interactions Involving Pest Aphids, Predatory 2-spot Ladybirds and Transgenic Potatoes Expressing Snowdrop Lectin for Aphid Resistance, 1999
  4. Ultrastructural Morphometrical and Immunocytochemical Analysis of Hepatocyte Nuclei from Mice Fed on Genetically Modified Soybean, 2002
  5. Ultrastructural Analysis of Pancreatic Acinar Cells from Mice Fed on Genetically Modified Soybean, 2002
  6. Fine Structural Analyses of Pancreatic Acinar Cell Nuclei from Mice Fed on Genetically Modified Soybean, 2003
  7. In Vivo Studies on Possible Health Consequences of Genetically Modified Food and Feed — with Particular Regard to Ingredients Consisting of Genetically Modified Plant Materials, 2003
  8. Ultrastructural Analysis of Testes from Mice Fed on Genetically Modified Soybean, 2004
  9. Transgenic Expressions of Bean Alpha-amylase Inhibitor in Peas Results in Altered Structure and Immunogenicity, 2005
  10. Genetically Modified Soy Bean in Rabbit Feeding: Detection of DNA Fragments and Evaluation of Metabolic Effects by Enzymatic Analysis, 2006
  11. Evaluation of Stress- and Immune-response Biomarkers in Atlantic Salmon for Different Levels of Bt Maize, 2007
  12. New Analysis of Rat Feeding Study with GM Maize Reveals Signs of Hepatorenal Toxicity, 2007
  13. A Long-term Study on Female Mice Fed on a Genetically Modified Soybean: Effects on Liver Ageing
  14. Intestinal and Peripheral Immune Response to MON810 Maize Ingestion to Weaning and Old Mice, 2008
  15. Biological Effects of Transgenic Maize NK 603xMon810 Fed in Long Term Reproduction Studies in Mice, 2008
  16. A Three Generation Study with Genetically Modified Bt Corn in Rats: Biochemical and Histopathological Investigation, 2008
  17. Can a Genetically-modified Organism-containing Diet Influence Embryo Development? A Preliminary Study on Pre-implantation Mouse Embryos, 2008
  18. Reduced Fitness of Daphnia Magna Fed a Bt Transgenic Maize Variety, 2008
  19. A Three Year Longitudinal Study on the Effects of a Diet Containing Genetically Modified Bt176 Maise on the Health Status and Performance on Sheep, 2008
  20. A Long Term Trial with Atlantic Salmon Fed Genetically Modified Soy; Focusing General Health and Performance before, during and after the Parr-smolt Transformation, 2009
  21. Health Risks of Genetically Modified Foods, 2009
  22. A Comparison of the Effects of Three GM Corn Varieties on Mammalian Health, 2009
  23. Maternal and Fetal Exposure to Pesticides Associated to Genetically Modified Foods in Eastern Township of Quebec, CA, 2011
  24. Long Term Toxicity of Roundup Herbicide and Roundup-tolerant Genetically Modified Maize, republished 2014
  25. A Long-term Toxicology Study on Pigs Fed a Combined Genetically Modified Soy and Maize Diet, 2013
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