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Posted: July 2014

Perspective Matters: Bias and Conflict of Interest in Studies About Genetically Modified Organisms

All research is initiated, planned and carried out by scientists who have a variety of interests that influence their choices, procedures, analyses, and conclusions. In other words, there is a larger-than-science context for every experiment and for the assessment of its results.

The question of whether genetically modified (GM) crops and food are safe is highly contested. Surveys of studies on the safety of GM crops have focused primarily on potential environmental and health risks to human beings. Studies on health risks usually involve giving animals feed containing GM products; no epidemiological studies on human health have been carried out.

Well-qualified scientists can come to strikingly different assessments of the significance of the same studies. It’s not hard to understand, for example, that ecologists concerned about biological diversity will carry out a study on the impact of a GM crop on the environment with different critical framework than a crop scientist who works for a biotechnology company that developed and sells the seed.

The universe of concern that informs a scientist’s work is usually not presented in a peer-reviewed scientific journal. Much is bracketed out through the objectified form of presentation. But because of the increasing degree to which science has become bound to commercial interests, more journals have begun to require at least a statement by authors about competing financial or professional interests.

Any scientist who carries out research knows the biases and predilections of the journals he or she hopes to publish in. The journal Transgenic Research, for example, publishes articles concerned with genetic engineering. The two editors are practitioners and vocal proponents of genetic engineering: Paul Christou helped invent the particle bombardment method of genetic transformation in plants while working at a genetics company that was later bought by the Monsanto corporation, which now holds the patents on the work that Christou invented; Bruce Whitelaw, the other editor of the journal, works at the Roslin Institute in Scotland and does research on genetically modified farm animals. It is perhaps not surprising that the articles in this journal that mention unintended effects usually say that none were found. The phrase “no adverse effects” is used in many articles and you are hard pressed to find any article that mentions adverse effects in this journal. Also, authors do not need to state whether they have competing interests.

In contrast, the journal Environmental Sciences Europe has an environmental/ecological focus. It deals with many areas, including genetically modified crops, especially in relation to regulation issues. The editor is a university scientist and an expert in bioanalytical environmental toxicology. In this journal you do find articles that report on unintended effects of genetic modification in relation to the environment. Authors must state competing interests and, interestingly, the journal has published exchanges between research groups reporting on unintended effects and others who contest those findings.

Unsurprisingly, a review of safety assessments of GM plants — by university scientists — found that “most of the studies demonstrating that GM foods are as nutritional and safe as those obtained by conventional breeding have been performed by biotechnology companies or associates, which are also responsible for commercializing these GM plants” (Domingo & Bordonaba, 2011). They found, overall, an “equilibrium” in the number of research groups suggesting that GM crops (mainly corn and soybeans) are as safe and nutritious as conventional crops and those that raise “serious concerns” about the safety of GM plants for animal and human consumption.

Diels et al. (2011) looked into whether there is any correlation between research outcomes and financial or professional conflict of interest. They evaluated 94 different studies and found that “either financial or professional conflict of interest was associated with study outcomes that cast genetically modified products in a favorable light.” Especially when the authors were affiliated with the industry was there a strong association with favorable findings. If the funding source alone was the source of conflict of interest, there was not this kind of strong correlation with positive assessment of results. However, of the 41 articles that included industry-affiliated authors, only seven declared their funding source.

There are small beacons of light in this often opaque landscape. I’m thinking, for example, of articles by Wendy Pline-Srnic, who as research scientist at the biotech company Syngenta, reported on unintended effects in GM cotton (see, for example, our report: Fruiting Morphology Was Altered When Glyphosate-Resistant Cotton Was Sprayed with Glyphosate).

A report by Séralini et al. (2012) generated major controversy in the scientific community and in the public debate about the safety of GM food. The researchers fed rats feed containing herbicide-resistant GM corn (NK603) over a period of two years — the first long-term feeding study of its kind. They reported that female rats fed with the GM corn containing feed died earlier and more of the animals died than control rats fed normal feed. They also were more likely to develop mammary tumors and male rats had pathologies in the liver and kidneys. The study was criticized in the popular press, in scientific journals and also by the European Food Safety Authority (EFSA). The latter came to the conclusion that the study was defective, both conceptually and methodologically. The journal retracted the article, which the authors had refused to withdraw (see Séralini et al. 2013).

Meyer and Hilbeck (2013) analyzed risk assessment studies of this GM corn that were subsequently released by EFSA. They included Monsanto’s technical report to EFSA. (Monsanto had developed the GM corn variety.) Using the same criteria that EFSA used to critique the Séralini study, Meyer and Hilbeck found that all the studies “suffered from comparable deficiencies [and] all of them satisfy or fail to satisfy the EFSA evaluation criteria to a comparable extent; the rejection of only one of the papers is, thus, not scientifically justified. ... We did find critical double standards in acceptance and rigor of the evaluation of feeding studies.”

Just as any statement about the function of a gene is only meaningful if one knows something about its organismic and environmental context, so are the results and conclusions of scientific studies highly context-dependent, and this context includes the universe of concern that informs all aspects of a scientist’s work. For this reason it is problematic that U.S. regulatory agencies rely solely on safety and environmental assessments that have been carried out by the companies that are themselves seeking approval for their genetically modified organisms.


Diels, J., M. Cunha, C. Manaia et al (2011). “Association of Financial or Professional Conflict of Interest to Research Outcomes on Health Risks or Nutritional Assessment Studies of Genetically Modified Products,” Food Policy vol. 36, pp. 197-203. doi: 10.1016/j.foodpol.2010.11.016

Domingo, J. L. and J. G. Bordonaba (2011). “A Literature Review on the Safety Assessment of Genetically Modified Plants,” Environment International vol. 37, pp. 734-42. 10.1016/j.envint.2011.01.003

Meyer, H. and A. Hilbeck (2013). “Rat Feeding Studies with Genetically Modified Maize — A Comparative Evaluation of Applied Methods and Risk Assessment Standards.” Environmental Sciences Europe vol. 25, pp. 33ff. Available online:

Séralini, G. E., E. Claire, R. Mesnage et al. (2012). “Long Term Toxicity of a Roundup Herbicide and a Roundup-Tolerant Genetically Modified Maize,” Food and Chemical Toxicology vol. 50, pp. 4221–31. doi:10.1016/j.fct.2012.08.005

Séralini, G. E., R. Mesnage, N. Defarge et al. (2013). “Answers to Critics: Why There Is a Long Term Toxicity Due to a Roundup-Tolerant Genetically Modified Maize and to a Roundup Herbicide,” Food and Chemical Toxicology vol. 53, pp. 476–83. doi:10.1016/j.fct.2012.11.007

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