No, ¨Science¨ has not confirmed that GMOs are safe

No, ¨Science¨ has not confirmed that GMOs are safe

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By Gabriela Vásquez

[Note: given that most of the coverage of the NAS report, including that of the Country, has focused on health effects, which seems to be the most worrying issue for a majority and that this article is already long enough as it is, this will focus on the part of the report that deals with said health effects, without going into environmental, agronomic aspects or the evaluation of new plant improvement techniques]

To begin with, the NAS does not maintain an “umbrella” position regarding the safety of GMOs, since it recognizes, like many other international organizations, that doing something like this is impossible since the same technique can produce different and unpredictable effects in each case. . The committee notes that a simple, general and authoritative response from the public on GM crops has been vigorously requested from the public, and that given the complexity of the issues relating to genetic engineering, they have not seemed appropriate to give it. Next, in a document of more than 400 pages, the committee develops its vision in this regard that, although it is more favorable to the use of GMOs in agriculture than that of most environmental groups, it is also much more conservative than that of many of its defenders (including El País). Instead of "science has confirmed that GMOs are safe," the report could have been summarized as "we haven't found what we haven't looked for."

It should be noted that the position of the committee, judging at least by the procedures described in the document, stands out for its respect for the different views regarding such a complex issue, as well as its active effort to avoid different types of possible biases. However, an important bias that should be taken into account when reading the document is that of the relationship of several of its members with important biotechnology companies and their associated organizations, starting with the study director herself, Kara Laney, who previously worked at the International Food & Agricultural Trade Policy Council (funded by Monsanto); The Food and Water Watch organization collects past employment relationships of at least twelve of the twenty-two members who have participated in the committee with the main global biotechnology companies or organizations financed by them.i Without this being a position that detracts from the authors of the study, it is one that should be known by those of us who approach it.

The NAS report, as on other occasions, presents a remarkable “sandwich” effect: several chapters outlining potential risks and perceived problems, limitations of research to date, and reasons for caution, surrounded by an opening and final chapter. that show a much more favorable vision, which is usually the one rescued, without nuances, by the main media and public relations agencies.

This effect has been pointed out since the 1989 NAS report, which in turn was used to justify a scientific consensus on the safety of GMOs, even when the text itself limited its own scope to experimental cultures and microorganisms in the USA. (Not even including Hawaii or Puerto Rico, as it is outside the continent): this was a document, in addition, that only considered possible environmental effects, since there were no studies on possible health effects. This did not prevent many sources from expanding in this area to the generality of applications of genetic engineering, which have since been baptized by "science" as "safe".

The artificial expansion of the areas of scientific consensus has been occurring since the first applications of genetic engineering emerged: as early as 1981 there were those who said that GMOs in general were safe and that there was consensus on the matter, even when it had only been carried out an experiment with a weakened strain of E. coli and even this had raised suspicions.ii The claim that the scientific consensus regarding the safety of GMOs is complete continues to this day, even though it is manifestly false. A manifesto signed by hundreds of scientists worldwide highlights that (even if they were wrong to doubt the safety of GMOs) the supposed scientific consensus does not exist.iii

The lack of pre-marketing trials that could limit the unforeseen effects derived from transgenesis was such that the first authorization for open field cultivation of a type of transgenic corn, in 1980, was granted years before it had been obtained. the first transgenic corn plant (let alone carry out trials with it) .iv At the beginning of this technology there were many who argued that nature was already so regulated that there were no niches for new organisms, so any GMO would die without human intervention, that agricultural GMOs would be unable to interbreed or that any genetically modified microorganism or virus would be safe if the parent was safe. v As today, many of these claims were made without studies to support them (and have shown, with the time, be false).

The lack of scientific consensus and the possibility of unexpected effects due to the genetic engineering process are recognized and addressed by the report. Regarding these unexpected effects, as in his previous report, he points out that they can also occur in some techniques considered within conventional improvement, such as radiation-induced mutagenesis or exposure to mutagenic chemicals (hereinafter, mutagenesis).

This is a technique whose use dates back to the middle of the 20th century, closely linked to the generation of new elite varieties since the Green Revolution, and whose possible adverse effects have not been studied. When drafting the 2001/18 GMO Directive the EU determined that these organisms were considered GMOs, but that they did not need to be subjected to pre-marketing testing or labeled due to their history of safe use. Whether that decision was appropriate, whether 50 years can be considered a history of safe use and whether it would be possible after this time to evaluate the possible effects that these crops have had is something that is beyond the scope of this In any case, the 2004 NAS report notes that both mutagenesis and the various techniques used for transgenesis cause changes throughout the genome at much higher levels than other "classical" plant breeding techniques. It is confusing that in some statements all plant breeding (including mutagenesis, which leads to GMOs) is put in the same bag, since there is such a great difference between one technique and all the others.

The report identifies two sources of unintended differences related to genetic engineering that could affect food safety:

Unforeseen effects of the genetic changes introduced on other characteristics of the food (for example, the presence or increase of a compound in the plant cell can cause changes in the metabolism of the plant that affect the abundance of other compounds)

Unforeseen effects associated with the genetic engineering process (for example, DNA changes resulting from the cell culture phase).

That is, the trait that is introduced may have more effects than it was expected to have, or the process of transformation of the plant and cell culture itself may produce changes in other places in the genome.vii When referring to changes derived from the culture cellular, the report refers to both genetic and epigenetic changes: it is interesting to note that, as a few years ago we would not have considered detecting this type of epigenetic changes (indeed, what we still know about epigenetics seems to be, according to Researchers themselves, surprisingly littleviii) it is possible that there are whole new “levels” of regulation that we have not yet discovered, and for which it is clearly not possible to measure impacts with current technique.

Since these effects can occur when using these techniques, the next logical question is whether our methods of detecting and avoiding them are sufficient. The idea that transgenic foods are analyzed in a very strict and exhaustive way is very widespread; however, the controls currently carried out have uncorrected deficiencies, which the report notes. Some of them are:

When talking about a specific case of evaluation of a Bt crop, he points out that it is not the EPA (government body) that carries out the tests, but that the company performs them and sends the results to the EPA (the same happens in the EU with EFSA). The raw data of these types of studies are not published nor are they available to the scientific community and the general public. In fact, the committee points out that not even they have had access to this data (which is protected by trade secret). (Comment to the report: this implies that in order for adverse effects to have been found in a pre-marketing trial, it would be the company itself that would have detected this effect, recognized it, registered it and sent it to the corresponding government agency. This would not have any meaning from a commercial point of view. The most logical thing would be that if a product had shown an adverse effect in the pre-marketing tests, the company would have simply withdrawn the application, and we would never have heard of this effect; or, if this effect it would have been subtle and not detected by the methods used [or chosen] if the product had passed the tests and entered the food chain.)

Internationally accepted protocols use small samples with limited statistical power, which may not be able to detect differences between treatments or find statistically significant differences that are not considered biologically relevant.

The data from studying cattle for long periods of time, although they do not indicate adverse effects, cannot serve as studies of possible effects in humans in chronic periods, among other things because these animals are young slaughtered.

Regarding the a priori evaluation of changes in the levels of “known” toxic substances: “the toxic properties of some plant compounds are understood, but most have not been studied”.

The detection of allergies to new proteins (both produced by the introduced gene and by a different gene that has been modified during the transformation / cell culture process) cannot be guaranteed with the methods currently used, for which post-marketing studies would be necessary .

In the studies carried out, differences have been found between animals fed with feed that contained transgenics and those fed with feed that did not contain them; these differences were statistically significant (that is, not due to chance but to treatment), but were not considered biologically relevant. However, what would be considered 'biologically relevant' had not been defined in advance, and the statistical power of the studies was not calculated. The differences found could have meant that there were adverse effects, but the methodology did not allow them to be detected. In other words, the report is correct in saying that "no adverse effects have been detected" (and also the headlines), but it also points out that this does not mean that they do not exist. In one of the cases described in the report, in fact, a feeding trial was carried out with a type of rice in which a gene for a protein of known toxicity had been introduced (as a positive control), without any adverse effects being detected. . Given this, the report points out the need to carry out more studies with a corrected methodology: the studies carried out to date, although it cannot be said that they indicate adverse effects, do not allow us to obtain conclusive data regarding safety.

With the data and studies currently available, no conclusions can be drawn about possible long-term effects in the human population. Even so, and due to the concern detected in the testimonies collected, the committee is concerned with using the available data (which, it points out, are insufficient and cannot be used to obtain conclusive data) to detect possible changes in the incidence of different chronic diseases . However, as they point out, this is a very shallow approach to detecting these problems. To detect them in reality, post-marketing studies that control a large number of variables would be needed, trying to ensure that the only difference between some groups and others was the consumption or not of transgenic foods (or of a certain food).

Several of these comments, but especially this last one, lead us to what could be one of the key points of dissension: the studies that are being done are not adequate to guarantee safety (understood as a level of guarantee similar to the one we have had with food not obtained by techniques with a high probability of generating unforeseen effects), but guaranteeing safety would be between very expensive and impossible. At various points in the report there is talk about “acceptable risk”: who decides what risk a population is willing to accept? Is this a necessarily scientific decision? It is logical that the decision should be supported by scientific data, among other things, but this does not imply that the entire decision-making process is framed in this area.ix)

The position of the report, and where it differs from the ecological position, is that in this situation the best we can do is to continue marketing these foods as before, perhaps putting some more technical means to detect these possible adverse effects, and hoping that if we detect some of these effects the food can be removed. This precaution-risk balance has been the one that has been chosen for years, and the one that has been followed with pesticides, synthetic chemicals, etc. The 20th century includes several cases of products and technologies for which scientists "did not detect adverse effects" (sometimes honestly and sometimes not), and that were good until they stopped being good. With the GMOs themselves, this balance is what has led to situations such as the proliferation of glyphosate-tolerant weeds such as the one indicated in the report, or to cases of the spread of transgenes in nature "that were never going to happen." It is the balance (saving the distances) that has led us not to recognize climate change globally until very late.

An alternative vision would be to limit these techniques to confined environments (with truly effective levels of confinement, control and information), where scientific research can lead us to a scenario in which we know enough about living systems so that these effects " unforeseen and unpredictable ”stop being so. In these confined settings, the consequences of using a GMO, good and bad, would affect only the person making the decision to use it (for example, a patient who wants to use insulin produced by a recombinant organism). Meanwhile, there are alternatives so that agriculture can advance and face the challenges that lie ahead, without having to risk adding to these challenges having to continue putting out fires.

I More information and references in Food & Water Watch, “Under the Influence: The National Research Council and GMOs”. May 2016.Available at:
Ii See minutes of the Large Scale Review Working Group of the RAC, April 22, 1981, in US Department of Health and Human Services (1982)
Iii ENSSER, “No scientific consensus on GMO safety”.
Iv Jones, Mary Ellen. "Politically corrected science: The early negotiation of US Agricultural Biotechnology Policy", Virginia Polytechnic Institute (1999), 63.
V Interview with Dr. Arnold Foudin, APHIS Deputy Director of Biotechnology Licensing, USDA, Washington (1997) cited by Jones, op.cit.
Vi For a longer development of this question, as well as references in this regard, see -engineer% C3% ADa-gen% C3% A9tica / mito-13-la-transg% C3% A9nesis-no-es-m% C3% A1s
Vii For a longer development of this question, as well as references in this regard, see -engineer% C3% ADa-gen% C3% A9tica / mito-12-la-ingenier% C3% ADa-gen% C3% A9tica-es
Viii Ledford, Heidi. Epigenetics: The genome unwrapped. Nature 528, S12 – S13 Available at:
Ix This topic has been widely debated elsewhere. An interesting reflection can be found in the document \ "Texts for a debate in Cuba \", freely available at for-a-debate-in-cuba


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