New Clear Vision

constructive commentary for the chronically farsighted

Dropping Like Flies?

February 20, 2013 By: NCVeditor Category: Devon G. Pena, Ecology

Applying the Precautionary Principle to GMOs 

by Devon G. Peña

We have been hearing a lot of protests lately from the pro-GMO camp about the ‘proven’ safety of genetically engineered foods. The most typical narrative comes in the form of a quote from a 2012 report issued by the respected and highly influential American Medical Association (AMA) and its Council on Science and Public Health. Here’s the proffered quote, which reveals the current dominant discursive frame used in defense of transgenic food safety:

Bioengineered foods have been consumed for close to 20 years, and during that time, no overt consequences on human health have been reported and/or substantiated in the peer-reviewed literature. However, a small potential for adverse events exists, due mainly to horizontal gene transfer, allergenicity, and toxicity.” (AMA 2012:i)

The AMA position has led many defenders of biotechnology to dismiss critics with a wave of the hand and repetition of a statement made by Mark Tester of the University of Adelaide: “If the effects are as big as purported…why aren’t all the North Americans dropping like flies?”

This hardly sounds like the definitive science-based defense of transgenic food safety but the biotech overlords have nevertheless declared an end to the debate, despite the fact that research in the predictive ecology, pathology, toxicology, and epidemiology of transgenic foods is still really very much in its infancy — twenty years of research is a beginning rather than an exhaustive and definitive take. It is irresponsible for anyone to suggest otherwise and I suspect those who do are not revealing conflicts of interest stemming from their relationships with the biotechnology sector.

Putting that substantial objection aside, there are some very serious methodological problems with the literature reviewed by the AMA panel. First and most fatal, from a methodological standpoint, is that the studies cited in the bibliography all involved research designs tracking health effects during a very short time span of 30-90 days. Indeed, the longest feeding study cited in the AMA report was only 3 months long. This is patently ridiculous and should shame the AMA into withdrawing this report and the resolutions associated with it.

Indeed, the longest feeding study cited in the AMA report was only 3 months long. This is patently ridiculous and should shame the AMA panel into withdrawing this report and the resolutions associated with it.

The reason the length of feeding studies is so critical to a sound research design is simple: Many of the more serious deleterious health effects of transgenic substances in food take many months and indeed often many years to develop.  The need for much longer time horizons has been borne out by several recent studies.

For example, last year we reported on a two-year feeding research study led by Gilles-Eric Séralini (2012), which found serious organ damage in rats fed GMO corn. The effects included severe kidney nephropathies (tissue damage), large mammary tumors (in females), impaired pituitary glands, and sex hormonal imbalances, among other effects. The Séralini study has provoked a flurry of objections by other scientists and an equal number of scientists have come out in support of the results of the study. Regardless, all this suggests is that the book on the health effects of GMOs is hardly closed. At the very least, we hold it is objectionable to suggest that the matter is settled one way or the other.

Another recent study involved a ten-year research design in Norway and was also published this past summer (2012). This means the results were available to the AMA panel, which either overlooked or chose to ignore it. The Norwegian study, which has not yet been published in English translation, is summarized in, a respected Internet source developed by Dr. Joseph Mercola, the Medical Director of the Optimal Wellness Center in Schaumburg, IL and a New York Times best-selling author.

According to this source, the Norwegian study used the longest time period research design to date (ten years). Significantly, the results indicated that “genetically engineered (GE) corn and corn-based products … cause obesity, and alter the function of the digestive system and major organs, including the liver, kidneys, pancreas, and genitals”. According to an interview with the lead researcher, Professor Åshild Krogdahl, and reported in in, the study was done at the Norwegian School of Veterinary Science (NVH), which focused on finding “any unintended effects of genetically modified food and feed.” According to the report prepared by Nina Kraft: “One of the findings suggests that genetically modified foods can make us fatter.”

The Norwegian research has been conducted in collaboration with researchers from Hungary, Austria, Ireland, Turkey and Australia. The project includes studies of the effects of GMO food in mice, pigs and salmon. According to Professor Krogdahl:

With different attack methods, we have tried to answer the question of what we should measure in humans and animals to reveal whether genetically modified food and feed can have unintended effects… This is a difficult task, but necessary. The results will be used to say something about the possible effects both in the relevant animal teams and to predict effects in humans… [H]owever, the experiments did not focus primarily on body weight, and weight gain is only one of the findings… Body weight is not a suitable indicator for the effects of genetically modified foods. Increased body weight can come from many things… We saw changes in the fish that ate genetically modified corn, regardless of age. We saw it in their digestive organs, liver, kidneys, pancreas, adrenals and sex organs. There was no major impact — all values were within what we might call normal… And those specimens that had eaten GM corn were thus slightly larger, they ate some more, their intestines had a different microstructure, they digested proteins slightly less efficiently, and the immune system had changed somewhat. We also took blood samples of fish and saw changes in the blood… [Original translation from the Norwegian]

However, the most troubling results of the study had to do with modified genes and proteins found in the blood:

[C]hanges in the internal organs are not in themselves dramatic. One sees physiological changes in body organs by consuming different foods – even when food is not genetically modified. But scientists cannot yet say whether the changes that occur when food is genetically modified are in a category of their own — whether for example, damage or disease result in the longer term… But we found something that we think is very interesting… These results are in line with findings showing that other large molecules can be recorded and have their effects in the body. The biological significance of the uptake of [foreign] genes in the body is not yet known.

Yet another more recent and equally troublesome study was done under the auspices of the European Food Safety Authority (EFSA). This study focused on the ubiquitous CaMV 35S promoter, the Cauliflower Mosaic Virus gene sequence, which is used to encode the desired genetic trait being inserted into the crop plant. Think of the CaMV as a delivery truck that carries the genetic material for, say, the expression of herbicide resistance. However, the study has found something that the gene giants swore would never occur: It found that the CAMV 35S promoter is also encoding a gene fragment of the virus itself! In other words, the delivery truck is also delivering itself as part of the genomic message.  The gene it is delivering is known as Gene VI. The EFSA study found that this encoding might have human health ramifications.

In the summary:

According to EFSA, they’ve known all along that certain GE crops contained Gene VI, which belongs to the Cauliflower Mosaic virus. This virus can infect a variety of different plants. It’s not a virus that can directly infect animals or humans. However, while the agency claims the virus poses no direct threat to animal or human health for this reason, others vehemently disagree. 

Finally, a team led by two well-regarded plant pathologists, Jonathan Latham and Allison Wilson, recently published another study verifying these concerns:

In general, viral genes expressed in plants raise both agronomic and human health [concerns]… This is because many viral genes function to disable their host in order to facilitate pathogen invasion. Often, this is achieved by incapacitating specific anti-pathogen defenses… Incorporating such genes could clearly lead to undesirable and unexpected outcomes in agriculture. Furthermore, viruses that infect plants are often not that different from viruses that infect humans… For example, sometimes the genes of human and plant viruses are interchangeable, while on other occasions inserting plant viral fragments as transgenes has caused the genetically altered plant to become susceptible to an animal virus… Thus, in various ways, inserting viral genes accidentally into crop plants and the food supply confers a significant potential for harm. (2007:85)

What the Norwegian, EFSA, and Latham/Wilson studies suggest is that the risk science on the human health effects of transgenic foods is still at a fairly early stage of development that leaves many unanswered questions and certainly poses significant new issues of greater complexity than many in the U.S. scientific community have been willing to admit. At the very least, the AMA should retract its position of no significant impacts and instead proclaim the truth: We need more research and especially studies that use a longer time horizon of three to ten years. The level of uncertainty that currently exists should behoove us all to insist on the adoption of the precautionary principle, at least with respect to labeling since it is literally too late to keep the gene-ie in the lab.


Latham, Jonathan and Allison Wilson 2007. Transcomplementation and synergism in plants: Implications for viral transgenes? Molecular Plant Pathology 9:1:85-103.

Seralini, Gilles-Eric, et al. 2012.  Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize. Food and Chemical Toxicology 50:11:4221-4231

Devon G. Peña, Ph.D., is a lifelong activist in the environmental justice and resilient agriculture movements, and is Professor of American Ethnic Studies, Anthropology, and Environmental Studies at the University of Washington in Seattle. His books include Mexican Americans and the Environment: Tierra y Vida (2005) and the edited volume Chicano Culture, Ecology, Politics: Subversive Kin (1998). Dr. Peña is the founding editor of the Environmental & Food Justice blog, and is a Contributing Author for New Clear Vision.

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