The Séralini Study and Long-Term GMO Toxicity

When GMOs were about to be launched on the market in the late 1980s, the principle of substantial equivalence was introduced. According to this principle, GMOs are considered substantially equivalent to their non-modified counterparts, thus eliminating the need to carry out long-term tests on the effects of their consumption. Many scientists, and public opinion in general, have long opposed this principle, claiming that the modifications introduced into the DNA cannot offer any certainty as to long-term effects.

One of these scientists is Marcello Buiatti, a professor of genetics at the University of Florence. “The control of possible risks was entrusted to the EFSA, the European Food Safety Authority, whose guidelines for the analysis of risk are inadequate. In particular, experiments to evaluate the possible toxicity of GMOs must be carried out within a time span of 90 days, which allows the study of short-term toxicity, but often is not long enough to reveal a series of diseases, including tumors, that show up over longer periods of time. Additionally, the guidelines insist on only a few of the possible analyses that could be carried out on the treated rats, neglecting important physiological, metabolic and anatomical-functional studies.” This has led to the need to carry out more thorough studies, and the results of one such study have just been published.

On September 19 a new study was released that seeks to shed light on the long-term consequences of a diet containing genetically modified organisms. The study, carried out by Italian and French researchers led by Professor Gilles-Eric Séralini, involved feeding 200 rats with diets containing variable amounts of GMOs for two years. The researchers used a Monsanto corn variety, NK603, modified to make it resistant to glyphosate, a herbicide sold under the name Roundup.

As the authors of the study themselves state, the results on their own cannot be considered decisive in the still-open debate about the possible effects of GMO consumption on human and animal health. But “the study was published in an international peer-reviewed journal [Food and Chemical Toxicology], which guarantees the scientific validity of the study and the professional reliability of the team who worked on it, because if that was not the case, it would bring into question the whole journal and everyone who works on it in various capacities,” commented Professor Federico Infascelli, who teaches animal nutrition at the University of Naples Federico II.

The doubts and questions that Séralini’s study brings up are certainly worrying, said Professor Infascelli, especially because “the authors compare the materials and methods that they use with those of previous studies aimed at showing that GMOs are not toxic, which for many reasons have proven to be much more incomplete than this one.”

The fact that short-term side effects have not been observed following GMO consumption means that they do not show immediate toxicity, but how much is known about chronic or subchronic effects linked to the ingestion of small quantities for a prolonged period of time? Toxicological studies normally conducted for the approval of a genetically modified food only last 90 days, while Séralini’s analysis observed the effects over a time period of two years. This kind of study is very complicated, not only because of its long duration and high number of animals, but also because it uses patented GM corn, generally owned by a multinational, which does not always allow its use for this type of analysis.

The 200 rats analyzed in Séralini’s study were divided into four groups. The first was fed with GM corn not treated with the herbicide, the second with GM corn treated with Roundup, the third with conventional corn and water diluted with some Roundup, and the fourth was the control group, fed conventional corn and water without added herbicide. The animals’ long-term mortality was evaluated, as well as the appearance and extent of tumors and any metabolic, physiological and anatomical diseases. The analysis of the results showed that the first three groups had much higher mortality rates, as well as serious damage and alteration to the functionality of the liver and kidneys.

Apart from the worrying differences in mortality rates and the fact that this represents the first study of such long duration, it is interesting to observe that for the first time, the consequences of a diet containing feed treated with the herbicide were studied. The herbicide was used just as it is used in the fields and as it can eventually be found as a residue in food or animal feed. Generally tests are only carried out on the herbicide’s active ingredient, decontextualizing it from the solution in which it is dissolved when it is sold. This makes a difference, as the solution contains other ingredients that help the action of the main active ingredient. In Séralini’s study, the concentration of Roundup in the water given to the rats was below the threshold allowed for drinking water, and yet it still had consequences on the animals’ health.

The study is now being closely examined by ANSES, the French food safety agency, and the EFSA, whose opinion is expected by the end of the year. Given the results of this study, it is hard not to ask why the EFSA does not carry out this kind of analysis and control, instead of leaving the testing to the same multinationals who then commercialize the products, and limiting themselves to checking that the documentation they provide is reliable.

In general this type of analysis should be carried out more often and there should be a clear law on food labeling, so that not only foods containing GMOs are identified (as required by regulations (EC) 1829/2003 and 1830/2003), but also products like meat and cheese deriving from animals fed with GM feed.

Federica Ferrario, who runs Greenpeace’s GMO campaign, sums it up: “The results of the study are very worrying and for this reason they should be thoroughly verified. The fact remains that there is no point in running useless risks, we need to apply the precautionary principle and immediately adopt a moratorium on the import and cultivation of GMOs at a European level.”

by Elisa Bianco, Slow Food Study Center
[email protected]

Photo: The cover of Nouvel Observateur announcing the study – Gilles-Eric Séralini