---
title: "Genetically modified food controversies"
chunk: 11/21
source: "https://en.wikipedia.org/wiki/Genetically_modified_food_controversies"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:17:47.717639+00:00"
instance: "kb-cron"
---

In 2007, 2009, and 2011, Gilles-Éric Séralini published re-analysis studies that used data from Monsanto rat-feeding experiments for three modified maize varieties (insect-resistant MON 863 and MON 810 and glyphosate-resistant NK603). He concluded that the data showed liver, kidney and heart damage. The European Food Safety Authority (EFSA) then concluded that the differences were all within the normal range. EFSA also stated that Séralini's statistics were faulty. EFSA's conclusions were supported by FSANZ, a panel of expert toxicologists, and the French High Council of Biotechnologies Scientific Committee (HCB).
In 2012, Séralini's lab published a paper that considered the long-term effects of feeding rats various levels of GM glyphosate-resistant maize, conventional glyphosate-treated maize, and a mixture of the two strains. The paper concluded that rats fed the modified maize had severe health problems, including liver and kidney damage and large tumors. The study provoked widespread criticism. Séralini held a press conference just before the paper was released in which he announced the release of a book and a movie. He allowed reporters to have access to the paper before his press conference only if they signed a confidentiality agreement under which they could not report other scientists' responses to the paper. The press conference resulted in media coverage emphasizing a connection between GMOs, glyphosate, and cancer. Séralini's publicity stunt yielded criticism from other scientists for prohibiting critical commentary. Criticisms included insufficient statistical power and that Séralini's Sprague-Dawley rats were inappropriate for a lifetime study (as opposed to a shorter toxicity study) because of their tendency to develop cancer (one study found that more than 80% normally got cancer). The Organisation for Economic Co-operation and Development guidelines recommended using 65 rats per experiment instead of the 10 in Séralini's. Other criticisms included the lack of data regarding food amounts and specimen growth rates, the lack of a dose–response relationship (females fed three times the standard dose showed a decreased number of tumours) and no identified mechanism for the tumour increases. Six French national academies of science issued an unprecedented joint statement condemning the study and the journal that published it. Food and Chemical Toxicology published many critical letters, with only a few expressing support. National food safety and regulatory agencies also reviewed the paper and dismissed it. In March 2013, Séralini responded to these criticisms in the same journal that originally published his study, and a few scientists supported his work. In November 2013, the editors of Food and Chemical Toxicology retracted the paper.  The retraction was met with protests from Séralini and his supporters. In 2014, the study was republished by a different journal, Environmental Sciences Europe, in an expanded form, including the raw data that Séralini had originally refused to reveal.

==== Carman et al. (2013) ====
Australian researcher Judy Carman, known for her long-standing critical stance toward GMOs, co-authored a study in which she reported adverse health effects associated with the consumption of genetically modified feed, highlighting signs of intestinal irritation in pigs as well as increased uterine thickness. The study was criticized by FSANZ, which pointed out serious flaws in its design, execution, and interpretation of the results. The agency emphasized that, although the authors attributed gastrointestinal and reproductive effects to the GM diet, relevant mycotoxins commonly found in grain-based feeds, such as trichothecenes and zearalenone, were not analyzed, even though these could explain intestinal inflammation and estrogenic effects independently of transgenesis. FSANZ also highlighted the lack of detailed information on the composition of the control and GM diets, which prevents the exclusion of the influence of other nutritional factors unrelated to the transgenic trait.
FSANZ noted that only a single GM diet was used, making it impossible to assess a dose–response relationship, and that there was no control of feed particle size, despite the authors themselves acknowledging the sensitivity of the porcine gastric mucosa to this factor. Group sizes and the method used to measure feed intake introduced substantial uncertainty, and mortality rates were considered abnormally high by industry standards, suggesting the presence of uncontrolled stressors. The agency also identified major deficiencies in the anatomical and pathological assessments: the intestines were not weighed, the intestinal mucosa and intestinal contents were not examined, and no histopathological analysis was performed to confirm inflammation, as the mere presence of hyperaemia is insufficient to characterize it. FSANZ further highlighted the absence of the expected changes in stomach weight relative to body weight, which contradicts the hypothesis of chronic inflammation. Marked differences in the gross appearance of stomachs from animals fed the same GM diet raised the possibility of acute stress effects, potentially associated with fasting and the slaughter process, without the study providing information to rule out this source of bias. In addition, FSANZ considered it problematic that regional lymph nodes, production performance parameters, and haematological tests were not evaluated, even though these could have provided objective evidence of inflammation or chronic blood loss. Finally, the agency explicitly disagreed with the authors' claim that standard haematological and serological tests are poor measures of inflammation, emphasizing that white blood cell counts and differentials, as well as biochemical parameters, are sensitive and widely used tools for this purpose.
The study was also criticized for having been published in the Journal of Organic Systems, which does not have an established scientific reputation and whose own editorial policy declares alignment with the principles of organic agriculture, thereby introducing an explicit editorial bias.

=== Nutritional quality ===
Some plants are specifically genetically modified to be healthier than conventional crops. Golden rice was created to combat vitamin A deficiency by synthesizing beta carotene (which conventional rice does not).

=== Detoxification ===
One variety of cottonseed has been genetically modified to remove the toxin gossypol, so that it would be safe for humans to eat.