Truth: EU research shows evidence of harm from GM foods

Myth at a glance

Research on GM foods commissioned by the European Union (EU) is often claimed to conclude that GM foods are safe. This is a misrepresentation of this research project, most of which was not designed to examine the safety of specific GM foods.

Three animal feeding studies from the project that did examine the safety of a GM food raise concerns, including differences in organ weights and immune responses in the GM-fed animals. These findings should be followed up in long-term studies.

An EU research project is often cited as providing evidence for GM crop and food safety. Those who have cited the project in this way include:

  • The GM industry lobby group ISAAA1
  • Jonathan Jones, a British Monsanto-connected scientist2,3
  • Nina Fedoroff,4 former science and technology adviser to US secretary of state Hillary Clinton
  • Máire Geoghegan-Quinn, European Commissioner for research, innovation and science.5

However, the report based on this project, “A decade of EU-funded GMO research”,6 presents no data that could provide such evidence – for example, from long-term feeding studies in animals.

Indeed, the project was not even designed to test the safety of any single GM food, but to focus on “the development of safety assessment approaches”.6 In fact, taxpayers would be entitled to ask why the Commission spent 200 million Euros of public money6 on a research project that failed to address this most pressing of questions about GM foods.

In the SAFOTEST section of the report, which is dedicated to GM food safety, only five published animal feeding studies are referenced.7,8,9,10,11

Two of these studies were carried out with a GM rice expressing a protein known to be toxic to mammals, in order to ascertain that the methodology used was sensitive enough to detect toxicity of a comparable level.78

None of the studies tested a commercialized GM food; none tested the GM food for long-term effects beyond the medium-term period of 90 days; all found differences in the GM-fed animals, which in some cases were statistically significant; and none concluded on the safety of the GM food tested, let alone on the safety of GM foods in general. Therefore the EU research project provides no evidence that could support claims of safety for any single GM food or of GM crops in general.

It is difficult to work out from the EU report how many studies were completed, what the findings were, and how many studies were published in peer-reviewed journals, because the authors of the report often fail to reference specific studies to back up their claims. Instead, they randomly list references to a few published studies in each chapter of the report and leave the reader to guess which statements refer to which studies.

In some cases it is unclear whether there is any published data to back up the report’s claims. For example, a 90-day feeding study on hamsters is said to show that “the GM potato is as safe as the non-GM potato”, but no reference is given to any published study or other source of data, so there is no way of verifying the claim.

An analysis of the three SAFOTEST studies that fed a GMO not previously known to be toxic is below.

Poulsen and colleagues (2007)10

A feeding trial in rats fed a GM insect-resistant rice found significant differences in the GM-fed group as compared with the control group fed the non-GM parent line of rice. Differences included a markedly higher water intake by the GM-fed group, as well as differences in blood biochemistry, immune response, and gut bacteria. Organ weights of female rats fed GM rice were different from those fed non-GM rice. Commenting on the differences, the authors said, “None of them were considered to be adverse”. But they added that this 90-day study “did not enable us to conclude on the safety of the GM food.”10

In reality, a 90-day study is too short to show whether any changes found are “adverse” (giving rise to identifiable illness). Yet no regulatory body anywhere in the world requires GM foods to be tested for longer than this subchronic (medium-term) period of 90 days.

The study also found that the composition of the GM rice was different from that of the non-GM parent, in spite of the fact that the two rice lines were grown side-by-side in the same conditions. This is clear evidence that the GM transformation process had disrupted gene structure and/or function in the GM variety, making it substantially non-equivalent to the non-GM line.

Schrøder and colleagues (2007)11

A study in rats fed GM Bt rice found significant differences in the GM-fed group of rats as compared with the group fed the non-GM isogenic (with the same genetic background but without the genetic modification) line of rice. These included differences in the distribution of gut bacterial species – the GM-fed group had 23% higher levels of coliform bacteria. There were also differences in organ weights between the two groups, namely in the adrenals, testes and uterus. The authors concluded that due to the study design, any toxicological findings “most likely will derive from unintended changes introduced in the GM rice and not from toxicity of Bt toxin” in its natural, non-GM form.11

The study found that the composition of the GM rice was different from that of the non-GM isogenic variety in levels of certain minerals, amino acids, and total fat and protein content.11 The authors dismissed these differences on the basis that they were within the range reported for all varieties of rice in the literature. However, comparing the GM rice to genetically distinct, unrelated rice varieties is scientifically flawed and irrelevant. It serves only to mask the effects of the GM process.

Despite this flawed approach, the level of one amino acid, histidine, was found to be markedly higher in the GM rice compared with the non-GM isogenic variety and outside the variability range for any rice.11 Does this matter? No one knows, as the required investigations have not been carried out. However, in other studies on rats, an excess of histidine caused rapid zinc excretion12 and severe zinc deficiency.13

In addition, the level of the fatty acid, stearic acid, was below the value reported in the literature for any rice11 and therefore the rice cannot be considered substantially equivalent to non-GM rice.

Kroghsbo and colleagues (2008)8

A study in rats fed GM Bt rice (this study in addition contained a group of rats fed GM rice expressing the known mammalian toxin mentioned above) found a Bt-specific immune response in the non-GM-fed control group as well as the GM-fed groups. This unexpected finding led the researchers to conclude that the immune response in the control animals must have been due to their inhaling particles of the powdered Bt toxin-containing feed consumed by the GM-fed group. The researchers recommended that for future tests on Bt crops, GM-fed and control groups should be kept in separate rooms or with separate air handling systems.8


The EU research project provides no evidence that commercialized GM foods are safe to eat and was not designed to provide such evidence. Instead, it was designed to develop methodologies to test GM food safety.

The three SAFOTEST studies examined above do not provide evidence of safety for GM foods and crops. On the other hand, they provide evidence that:

  • Over a decade after GM foods were released into the food and feed supplies, regulators still have not agreed on methods of assessing them for safety
  • The GM foods tested were markedly different in composition from their non-GM counterparts – probably due to the mutagenic or epigenetic (producing changes in gene function) effects of the GM process
  • The GM foods tested caused unexpected, potentially adverse effects in GM-fed animals that should be investigated further in long-term tests
  • The authors were not able to conclude that the GM foods tested were safe.


  1. International Service for the Acquisition of Agri-biotech Applications (ISAAA). EC report on “A Decade of EU-Funded GMO Research” describes “tailored” bioenergy crop research project. Crop Biotech Update. 2010. Available at:
  2. Doward J. Scientist leading GM crop test defends links to US biotech giant Monsanto. The Guardian. Published July 18, 2010.
  3. Jones JD. The cost of spurning GM crops is too high. The Guardian (UK). Published July 21, 2011.
  4. Fedoroff NV. Engineering food for all. New York Times. Published August 18, 2011.
  5. European Commission. Commission publishes compendium of results of EU-funded research on genetically modified crops. Brussels, Belgium; 2010. Available at:
  6. European Commission Directorate-General for Research and Innovation, Biotechnologies, Agriculture, Food. A decade of EU-funded GMO research (2001–2010). Brussels, Belgium; 2010.
  7. Poulsen M, Schrøder M, Wilcks A, et al. Safety testing of GM-rice expressing PHA-E lectin using a new animal test design. Food Chem Toxicol Int J Publ Br Ind Biol Res Assoc. 2007;45(3):364-377. doi:10.1016/j.fct.2006.09.003.
  8. Kroghsbo S, Madsen C, Poulsen M, et al. Immunotoxicological studies of genetically modified rice expressing PHA-E lectin or Bt toxin in Wistar rats. Toxicology. 2008;245:24-34. doi:10.1016/j.tox.2007.12.005.
  9. Knudsen I, Poulsen M. Comparative safety testing of genetically modified foods in a 90-day rat feeding study design allowing the distinction between primary and secondary effects of the new genetic event. Regul Toxicol Pharmacol. 2007;49(1):53-62. doi:10.1016/j.yrtph.2007.07.003.
  10. Poulsen M, Kroghsbo S, Schroder M, et al. A 90-day safety study in Wistar rats fed genetically modified rice expressing snowdrop lectin Galanthus nivalis (GNA). Food Chem Toxicol. 2007;45:350-63. doi:10.1016/j.fct.2006.09.002.
  11. Schrøder M, Poulsen M, Wilcks A, et al. A 90-day safety study of genetically modified rice expressing Cry1Ab protein (Bacillus thuringiensis toxin) in Wistar rats. Food Chem Toxicol. 2007;45:339-49. doi:10.1016/j.fct.2006.09.001.
  12. Freeman RM, Taylor PR. Influence of histidine administration on zinc metabolism in the rat. Am J Clin Nutr. 1977;30:523-7.
  13. Wensink J, Van den Hamer CJ. Effect of excess dietary histidine on rate of turnover of 65Zn in brain of rat. Biol Trace Elem Res. 1988;16:137-50. doi:10.1007/BF02797098.