European studies disprove Seralini’s GMO maize tumor claims

By Joan Conrow

June 7, 2018

Three European studies have disproved Gilles-Éric Séralini’s widely circulated claims that genetically modified maize (corn) induces tumors in rats.

Séralini, a professor at the University of Caen, published his sensational claims in Food and Chemical Toxicology in September 2012, and used them to call for long-term GMO feeding studies. Though the publication later retracted his study, anti-GMO groups have continued to circulate Séralini’s conclusions in a bid to stoke fears about the safety of GM foods.

Now three studies — GRACE and G-TwYST, funded by the European Union, and GMO90+ in France — have refuted Séralini’s main conclusions about the toxicity of herbicide-tolerant (Roundup Ready) maize. The research — conducted to address concerns raised by the Seralini study and provide the EU with guidance on the need for long-term studies — identified no potential risk from the product.

“European consumers must be informed of the results of these studies, [which] should reassure them on the quality for their health of genetically modified plants authorized for commercialization and on the European evaluation procedure, already the most rigorous in the world,” the French Association of Plant Biotechnology (AFBV) stated. “In addition, these new studies contradict Seralini’s proposal on the need to carry out long-term studies.”

The EU requires applicants to conduct a 90-day feeding assessment study on whole GMO food/feed before it can be placed on the market. The original assessment conducted for herbicide-tolerant maize identified no potential risk to humans.

“The G-TwYST (GM Plant Two Year Safety Testing) data from 90-day and long-term rodent feeding studies did not identify potential risks as well, and therefore support the results from the initial analyses,” according to the study’s conclusions and recommendation’s document, which was presented at an April 29, 2018 conference in Bratislava, Slovaki.

“It was concluded that there were no adverse effects related to the administration of the GM maize NK603 cultivated with or without Roundup,” the report stated.

The research included a combined chronic toxicity and carcinogenicity study, and “no toxicologically relevant effects related to the GM maize NK603 or the GM maize NK603 treated with Roundup were observed,” the report stated.

The GRACE (GMO Risk Assessment and Communication of Evidence) study conducted two 90-day feeding trials on rats using two different varieties of maize genetically modified to resist insect pests and tolerate glyphosate. “The results showed that the two GM maize varieties tested did not trigger any negative effects in the trial animals,” according to a report on the findings.

Additionally, data showed the GM maize did not affect the immune functions tested in both of the 90-day studies.

The GRACE study was published in Archives of Toxicology.

The GMO90+ study also assessed the Bt maize, using a 180-day feeding trial, and found no negative effects on the rodents.

In addition to addressing concerns raised by the Séralini study, the research was intended to provide the EU with guidance whether it’s necessary to conduct a two-year carcinogenicity feeding trial on rats with whole food/feed. “The necessity to perform a feeding trial with whole food/feed should be carefully evaluated given the high number of animals needed,” the G-TwYST report concluded.

Due to the controversial nature of the research, “substantial efforts were made to ensure stakeholder engagement, transparency and data accessibility,” the G-TwYST report stated. “These included stakeholder engagement in both project plans and results; making available draft research plans and preliminary research results (all data produced) for stakeholder scrutiny; a procedure for discussing, systematically considering and responding to all stakeholder comments as well as tracking how the comments were considered in the project; detailed documentation and transparency of all steps; open access publications, and an open access repository for raw data to be available following academic publication of the results. The approach received high praising from the majority of stakeholder participants.”

The report further noted: “These challenges and the considerable resources and efforts needed do not suggest this approach to be used on a routine basis. Yet, in case of highly contested scientific-technical issues and polarized views, the approach remains an interesting option to improve the quality and social robustness of research.”

The results from the experiments are now published on