GM Foods: A Moment of Honesty

Note: the FieldQuestions blog has been dormant for several months due to some academic writing projects and fieldwork. But with a new debate raging on GMO labeling, it’s time to get back to it.

As the latest controversy over GMO’s unfolds – this time it’s about a House Bill that would ban labeling laws – it’s time for a moment of honesty about science and safety. Of course safety is hardly the only bone of contention in GMO debates, but safety is the issue that’s most hotly contested and that’s most central to the labeling bill.

Rep. Mike Pompeo, the sponsor of the bill, writes that activists are misleading consumers with false claims about unsafe food.  Actually, “more than 100 research projects over 25 years” have “affirmed and reaffirmed the safety” of GM foods.

I must point out to my GMO-doubting friends that Pompeo’s statement about the research is accurate. A lot of studies have failed to find any health risk for any GM food. Bizillions of meals with ingredients from GM crops have been eaten with no direct linkage to health problems.  So for those of us who study GM crops professionally, there eventually comes a point to set aside allegiances and emotions and take a frank and careful look at the science.

I have reached that point, but I know of someone else who reached a similar point, someone who was ideally positioned to speak on issues of technology and food and safety. The late Dr. Norman Borlaug, “Father of the Green Revolution” and Nobel laureate, was a passionate proponent of GM crops. This humanitarian scientist captured something important about modern agriculture and how to deal with its critics. Borlaug realized that when lives were at stake, it is appropriate to be impatient, even downright irate, with anti-science critics of valuable technologies.

How to Deal with Anti-Science Fear Mongers

Borlaug made the case against anti-science fear mongers most memorably in a blunt speech to the Food and Agriculture Organization that was later reprinted in the New York Times.[1] From the start it was clear that the time for kid gloves was over. The “vicious, hysterical propaganda campaign,” he began, “by fear provoking, irresponsible environmentalists,” was a detriment to world society. “Vitriolic” attacks against the technology were “distorted” and “one-sided”, making no mention of the technology’s importance in “protecting our food and fiber production.”

These critics are actually few in number, but “extremely effective force in lobbying for legislation” and “brainwashing the general public” with “scare tactics…based on bits of unsubstantiated scientific data, questionable ethics, emotion and oratory.”

Then he came to safety. Despite claims that the technology is dangerous, the Surgeon General is clear that no available information supports this. The safety record of the technology is “truly remarkable,” given the “prolonged exposure by hundreds of millions of people.

Despite the wild rhetoric of the environmentalists about…damage to both human and wild life,” he continued, “as more and more scientific evidence accumulates, the charges … become less and less convincing.” The technology is not “causing any discernable injury to man.”

OK let me come clean.  While it is true that late in life Borlaug was a combative defender of GM crops, this speech was actually delivered in 1971. The agricultural technology he was defending was not genetic modification of crops, which would not appear for over a decade. It was DDT. And as rash as Borlaug’s claims may sound today, they were accurate: hundreds of millions of people had been exposed to DDT, and no injury to human health had been discerned — and wouldn’t be for 36 more years.  The real lesson here is not how to be irate with science’s critics, but how to be humble about science’s weaknesses.

A Long Record of Safety

DDT came into civilian use in 1945. In the 1950s it was used heavily for mosquito control and heavier still in agriculture – particularly in the US, where increasingly fertilized and irrigated grain fields led to a boom in agricultural insect pests.


Snorting a few lines of nice safe DDT.

Many scientists were sure it was safe from the beginning. Entomologist Kenneth Mellanby reported that when lecturing about DDT in the years after World War II, he “frequently consumed a substantial pinch of DDT, to the consternation of the audience, but with no apparent harm to myself, either then or during the next 40 years.” Entomology professor Gordon Edwards would eat a teaspoon of DDT each week, supposedly “proving” it safe.[2] Early evidence indicated it was harmful to birds but not humans. By 1962, even Rachel Carson’s Silent Spring could cite no solid evidence of impacts on human health.

Still, the US banned DDT in 1972, to Borlaug’s dismay. It remained in the environment, but as more scientific evidence accumulated in the following years, claims of human health impacts continued to be “less and less convincing.” In 1979, the World Health Organization reported that “the safety record of DDT is phenomenally good.” In 1991, agricultural ecologist Gordon Conway and sustainable agriculture expert Jules Pretty published Unwelcome Harvest, an exhaustively-research book on agriculture and pollution.[3] Their conclusion: DDT can severely affect birds, “Yet in humans there is little evidence of a hazard to health, except at very high dosages.”  But DDT proponents even dismissed claims that birds were being affected.

Many became convinced that environmental DDT was contributing to the rising rates of breast cancer, but over 30 separate studies failed to find a link between breast cancer and bodily levels of DDT (or its metabolite DDE).[4] Breast cancer activists and environmentalists lobbied congress to fund research on cancer hotspot areas in the 1990s. This led to the large-scale Long Island Study, focused on breast cancer where pesticides had been used heavily in the past. But in 2002 when results began to appear, the findings again seemed to exonerate DDT.

Many saw this as the end of the road for DDT critics. New York Times reporter Gina Kolata pointed out the lack of conclusive evidence of environmental causes of cancer.[5] She quoted the Long Island Study leader who said the data were “very, very conclusive”: the chemicals they studied “are not associated with breast cancer.”conclusive A large-scale meta-analysis of DDT (and PCB) studies around the same time also failed to find a link with breast cancer. “I think we have the answers” said the head of the meta-study. Anyway, if “the risks are very small and exposures took place in the distant past,” then “it may be beyond the capacity of science to find it.” Although breast cancer activists rejected the Long Island findings, Kolata wrote that “others said it may be time to close the books.”

Looking in All the Wrong Places

The problem with all this is that if you’re looking in the wrong place, it doesn’t really matter how many times or how carefully you look. Environmental factors in breast cancer risk turn out to be strongly age-related. Studies of radiation exposure show that the breast is most likely to develop cancer if exposed in utero, before menarche, and before first pregnancy – but not later. None of the studies of DDT and breast cancer – including the Long Island study that supposedly “closed the book” – measured exposure during these critical windows of breast development.

Come to think of it, how could you even do such research? DDT has been banned for decades. How could you compare incidence of breast cancer – which usually strikes women in adulthood – with DDT exposure early in life? Sounds like something “beyond the capacity of science.”

It isn’t. In a path-breaking study published in 2007,[6] epidemiologist Barbara Cohn of UC-Berkeley’s Public Health Institute used a remarkable dataset on over 20,000 pregnant women and children in Oakland collected in 1959-1967. These were peak years for DDT use in the US. For each individual they knew the age when the spraying started, and they also measured the levels of DDT and DDE in the blood. Then they tracked down the women’s medical records nearly 40 years later. If you are a woman, or if you know any women, you need to know the results.


In the US, 1 in 8 women will develop breast cancer. More stats here. (Men get breast cancer too, but on a much smaller scale.)  There is no single cause; DDT is only one contributing factor.

It turned out that women born before 1931, who were almost all past puberty when the spraying started, were no more likely to develop breast cancer than the control cases. That was generally consistent with the dozens of earlier studies. But women who had the highest exposure to DDT before the age of 14 were five times as likely to develop breast cancer later in life. All the other studies had missed this critical period.[7]

This was only the beginning. Cohn’s team has now completed a 54-year follow-up on daughters born to women in the Oakland study: daughters whose mothers had high levels of DDT while pregnant were more likely to develop breast cancer.[8] Another study found that boys whose pregnant mothers had high levels of DDT were also more likely to develop testicular cancer.[9] Ongoing research is investigating a range of other health impacts.

Even now, no one understands the mechanisms behind the carcinogenic effects. DDT is known to disrupt endocrine systems; the cancer-causing mechanism may specifically have to do with estrogen. Hopefully this research will stimulate experiments to isolate the mechanisms involved.

But what we do know is that it took us 62 years to even begin to “discern the injury” to humans caused by DDT. With one in eight American women today developing breast cancer, Dr. Borlaug’s scathing denunciation of anti-science fear mongers now seems particularly reckless and scientifically naïve.


There are lots of wonderful images and videos of gleeful kids being directly sprayed with DDT. But the vast majority of DDT was used for overproducing grains, not controlling mosquitoes. Much of it ended up in the water or in the food chain.

But Aren’t GM Crops Different?

Are there lessons here for debates on genetic modification? GM crops are not DDT. But frankly, most of the differences between GM crops and DDT should only heighten our concern. Consider these three differences:

1. DDT is one chemical; GM crops are all different. Crop plants are different and the gene constructs biotechnologists paste together are different; moreover each “transformation event” (meaning when the gene construct is inserted into one of the target plant’s chromosomes) is unique. Each transformation event raises a host of questions, only some of which have to be answered before a plant is released (more on this...). This is why the World Health Organization says

Different GM organisms include different genes inserted in different ways. This means that individual GM foods and their safety should be assessed on a case-by-case basis and that it is not possible to make general statements on the safety of all GM foods.

It’s also why one of the corporate scientists in charge of the safety assessment of the world’s first GM food (Calgene’s Flavr-Savr tomato) writes about the “absurdity of claiming that all GMO’s are safe.”

2. Health impacts for GM crops will be even harder – actually much harder – to detect than for DDT. DDT is measurable in the blood; some effects of highly processed ingredients made from GM plants may be “beyond the capacity of science to find.”

3. Many more “non-industry” scientists have a professional and personal (and sometimes financial) stake in GMO’s than they did in DDT. Borlaug was not financially dependent on the pesticide industry (although he did appear at press conferences organized by DDT manufacturers[10]); however academic research on GM plants is routinely funded by the biotech industry, and researchers are beholden to biotech corporations for access to patented genes. Academic biotechnologists (along with a small pack of journalistic attack dogs, mostly funded by the industry) swarm on anyone – including scientists – who point to uncertainties about GM crops. They often evince the same scorn that Borlaug showed towards the “hysterical propaganda” on DDT. In fact the words are almost identical.

Billions of people have eaten genetically modified food over the past two decades. Not one problem has been found…

And the “The Debate About GMO Safety Is Over“…

A frank look at the science points us in the opposite direction.  The billions of meals with traces of one or another GM ingredient means even less than the exposure of hundreds of millions to DDT.  The claim that any GM crop is known to be safe … let alone all GM cropslet alone all future GM crops — is reckless, foolish, and scientifically silly. And if Congress actually uses this as a justification for a bill prohibiting state labeling laws, then it has reached a new low.


1. Delivered as the McDougall Memorial Lecture at the FAO Conference, 8 Nov 1971.  Later excerpted in Borlaug, N.E., Mankind and Civilization at Another Crossroad: In Balance with Nature – A Biological Myth. BioScience, 1972. 22(1): p. 41-44.   Borlaug, N.E., DDT, the First Domino, in New York Times. 1971. p. 13.
2. Wurster, C. 2015 DDT Wars: Rescuing Our National Bird, Preventing Cancer, and Creating the Environmental Defense Fund. New York: Oxford Univ. Press, p. 154.
3. Conway, G. and J. Pretty, Unwelcome harvest: agriculture and pollution. 1991, London: Earthscan.
4. Cohn, B.A., Developmental and Environmental Origins of Breast Cancer DDT as a Case Study. Reproductive Toxicology (Elmsford, N.y.), 2011. 31(3): p. 302-311.
5. Kolata, G., What Causes Cancer: Can Science Find the Missing Link?, in New York Times. 2002: New York, N.Y. p. 2-c1.
6. Cohn, B.A., et al., DDT and Breast Cancer in Young Women: New Data on the Significance of Age at Exposure. Environ Health Perspectives, 2007. 15(10): p. 1406–1414.
7. Eskenazi, B., et al., The Pine River Statement: Human Health Consequences of DDT Use. Environmental Health Perspectives, 2009. 117(9): p. 1359-1367.
8. Cohn, B.A., et al., DDT Exposure in Utero and Breast Cancer. The Journal of Clinical Endocrinology & Metabolism, 2015.  Online (in press) jc.2015-1841.
9. Cohn, B.A., P.M. Cirillo, and R.E. Christianson, Prenatal DDT Exposure and Testicular Cancer: A Nested Case-Control Study. Archives of Environmental & Occupational Health, 2010. 65(3): p. 127-134.
10. Cullather, N., The hungry world: America’s cold war battle against poverty in Asia. 2010, Cambridge MA: Harvard Univ. Press, p. 247.
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56 Responses to GM Foods: A Moment of Honesty

  1. Lisa Isenhart says:

    Great article! I really enjoyed reading this.

    Best, Lisa

  2. foodie62 says:

    Incredible. But why was the father of the Green Revolution such a DDT booster?

    • Glenn says:

      The Green Revolution crops — both wheat and rice — were heavily dependent on fertilizer – irrigation – pesticide. The crops were not inherently better, just more responsive to industrial inputs. Borlaug said that if DDT was banned, his life’s work would be “wasted.”

    • LFP says:

      Don’t be fooled by the name: the “Green Revolution” was the beginning of high input, chemically intensive industrial agriculture. It raised yields but also increased cancer rates, soil erosion, and other negative impacts that are conveniently ignored by boosters.

      • borderglider says:

        And don’t forget over 200,000 suicides by Indian farmers as a direct result of the massive debts which the ‘Green Revolution’ imposed on them. If an indebted farmer dies there, his debt dies with him, so his family get to keep the land. Tragically, most of them died by swallowing Paraquat – supplied by the Green Revolution corporations and banks.

      • Glenn says:

        Actually the crop most implicated in Indian farmer suicides is cotton which is not a Green Revolution crop — the Green Revolution referring to input-intensive wheat and rice introduced in the mid-late 1960s. Input-intensive cotton spread in the 1990’s. Your information on debt being retired when a farmer dies is incorrect. Pesticide is indeed a common method of suicide, but it comes from the ubiquitous agricultural input shops, not banks.

  3. LFP says:

    Excellent post, Glen. Balanced, thoughtful, and evidence-based, as always. So refreshing to read an informed opinion instead of the continual deluge of industry propaganda from scientifically and agriculturally illiterate urbanites in the media.

    One point to ponder for a future post. While the safety of GM crops themselves is currently unresolved as you point out, let’s remember that the vast majority of such crops are designed to be sprayed with glyphosate, which much more clearly does have safety issues. As you know, those anti-science hippies at the WHO recently categorized glyphosate as a probable carcinogen, their second highest evidence level (see ).

    Since the advent of GM technology, the use of glyphosate and other agrichemicals has gone through the roof since 1996 (see ). I would argue that this was the industry’s plan all along — and they’ve succeeded brilliantly, in part by portraying critics as anti-science hysterics in the Borlag mold.

    • Glenn says:

      In some areas, insecticide spraying has dropped on some crops (like cotton) has dropped with Bt seeds, but herbicide spraying has gone through the roof. And a clear and complete picture of the long-term health impacts of glyphosate will be very very hard to construct. The new generation crops are resistant to 2,4-D and dicamba; 2,4-D has been in use for a long time but the picture there isn’t clear either.

  4. Any method of crop or livestock improvement can introduce deleterious mutations and potentially make a food product unsafe. There are unintended consequences from conventional breeding, such as the lenape potato that had to be abandoned for its toxic levels of solanine.

    What makes genetic engineering different is that we know what genes cause the trait we want, and can monitor for unintended changes in the genome. Backcrossing the transformed plant with the parent line that produced it eliminates unintended insertion effects and ensures the insertion is stable. Sequencing is used to compare the genome before and after to make sure that only one copy of the transgene is inserted and it is in a suitable location. The most likely effect of breaking something is to impact the plant’s viability. So in addition to scrutinizing the genome the plants are monitored carefully.

    If there’s a basis to subject the products of biotechnology to further regulatory review and labeling of potential unwanted effects, that rationale must be doubled for conventional breeding where there may be unwanted DNA accompanying a new trait, but no pre-market safety review with the FDA, EPA and USDA as exists for traits produced with biotechnology.

    The precise changes involving genes with known products that are scrutinized for hazard before release sure sounds safer than the product made with unknown new genes making unknown proteins and no pre-market review.

    • Glenn says:

      Ah, the whole enterprise of crop alteration via molecular biology is imbued with certainty.

      Sounds like somebody read my recent article on the demise of scientific uncertainty and was inspired to demonstrate what I was writing about.

      • I hope the careful reader will note from my opening that Any method of crop or livestock improvement can introduce deleterious mutations and potentially make a food product unsafe.

        This is not about certainty as a state where there is no doubt of harm, but rather relative uncertainty as to the nature of changes made in various methods of creating new traits.

        If you can show me why there is more certainty about the safety of traits produced by wholly unknown genes than traits produced by known and well-studied genes, I’ll reconsider my opposition to mandatory labeling on the basis of method.

        Thank you for the paper. I find the intro material about schismogenesis especially interesting and it reflects my experiences as a part of the anti-GMO movement. Today I do my best to stress the relative risks, rather than comparing the products of biotechnology to an imagined “no risk” scenario that doesn’t exist.

    • Belinda says:

      “Backcrossing the transformed plant with the parent line that produced it” does not eliminate unintended insertion effects. In fact, the vast majority of hemizygous transformed plants headed for the product development pipeline are crossed so as to result in GE plants homozygous for the inserted DNA, and therefore homozygous for any insertional mutation that may have occurred during the genetic engineering process.
      Yes, sequencing can be used to determine where in the GE plant the DNA was inserted, and if it was inserted into a protein-coding gene, mutating that gene…if the genome of the recipient plant has been sequenced (which is not the case for some plants undergoing GE like banana, e.g.). But the current regulatory system in the US has so many loopholes in it that, depending on the design of the GE plant, sequencing its genome may not be required prior to commercialization.
      As to making sure that an insertion is in a “suitable” location…we really don’t know enough about plant genomes to be able to identify such a place.
      What we need is more science on the imprecise aspects of genetic engineering and on plant genomes in general, a new process in the US for regulating them on a case-by-case basis and, until we can identify “suitable” locations in plant genomes, we should label GE foods so that American consumers can decide for themselves whether GE products sound safer than foods produced using traditional breeding methods.

      • Thank you for the correction, I definitely oversimplified things and took it as an opportunity to do further reading and discussing with friends in the industry.

        The transgene is introgressed into an elite line that is well suited for expressing it. This involves repeated crosses with marker-assisted selection, and allows for moving only* the transgene to new lines. Where you quote me I am mainly referring to the unintended consequences to the genome outside of the inserted gene that won’t persist after enough crosses.

        It would obviously be possible to move a damaged transgene with introgression, but it would likely never be done because both genotype and phenotype are scrutinized carefully. To whatever degree there’s a risk of introgressing a damaged gene that doesn’t manifest in a measurable way, it isn’t limited to biotech methods of transformation.

        Introgression is also used this way by some conventional breeders. Unintended consequences are expected during the development process regardless of breeding method. Whenever DNA is recombined, including by sex, mutations might occur that render the offspring non-viable or defective. There’s an open access review describing studies done to quantify the changes made by genetic engineering titled Evaluation of Genetically Engineered Crops Using Transcriptomic, Proteomic, and Metabolomic Profiling Techniques:

        This survey on the profiling of GE crop lines with agronomic traits, but without deliberate modifications to metabolic pathways, reveals that some differences exist when compared with control lines. However, the available data on various conventional lines consistently show more differences. This has to be linked to the fact that GE lines have been selected by a process based not only on the suitable expression of a new trait but also on phenotypic and compositional equivalence with a close comparator, followed by a number of crosses to introgress the new trait into elite lines. A number of environmental factors (field location, sampling time during the season or at different seasons, mineral nutrition) have also been shown, consistently, to exert a greater influence than transgenesis.

        There’s caveats about certainty given in the work, but our knowledge and methods will continue to improve over time. It takes an average of 13 years and costs $136 million to bring a new GE trait to market. This open access paper published by Monsanto titled Genetically Engineered Crops: From Idea to Product describes the different phases of development including methods of evaluating safety.

        The current regulatory schema is expensive and that limits competition in a way that is problematic, but I wouldn’t loosen it for that reason alone. Whether they are regulated “enough” is a hard question because every rationale I see for adding more regulations also applies to conventionally bred traits. In general breeding is done safely because developers take great care. They expect unintended consequences from every method of plant improvement, and eliminating unsuitable candidates is routine and usually unremarkable.

        * To really be certain you have to sequence and check your work.

  5. Jack Wiegand says:

    Arguments from ignorance simply aren’t very interesting. By your own admission here, the extant research leaves as much reason to be concerned about the safety of GM crops as there is to be concerned about the safety of crops grown by left-handed farmers, or by farmers who wear shoes. Why not push for these labels? Sure, we’ve never observed any detriment from those growing conditions, and there’s no basis within modern science for thinking these things should pose some unilateral risk, but that doesn’t mean there isn’t one. I mean, DDT, right? Just like farmers with shoes, we went decades without observing any harmful effects of DDT. And while DDT is only one chemical (compound), shoes are made of LOADS of chemicals. And of course, all the other food we eat doesn’t go through anything resembling the sort of rigorous testing that GM products do, but since science could be wrong, all that testing doesn’t mean anything until it gives us a negative, right?

    The problem here is that you (and many politicians/ideologues) are using colloquial language to describe science, which is forgivable; it’s unavoidable when communicating science to the public. To most people, “safe” means completely risk-free, which is an unscientific concept. However, to say that the extant literature raises no significant health concerns with regards to GMO is true, is easy to understand/communicate, *is* reflective of an overwhelming consensus within the field, and isn’t the view that you’re promoting here.

    • Glenn says:

      Thanks for the heads-up on the farmer/shoe issue. The cattleman I lease pasture to wears leather boots; he walks on my grass, the cows eat the grass, I eat the beef, and I suspect it affects my brain, making me want to sit in my office reading about the history of agriculture. I sometimes buy fresh vegetables from a hippie couple; they both wear Birkenstocks at the farmers market but the woman once told me they work in their garden barefoot. Good to know.

  6. A. Patel says:

    Fair enough. Good point about Borlaug and the crazy environmentalists. But there is another relationship between GM crops and dangerous insecticides that you left out. Adoption of GM crops has led to REDUCTIONS in use of carcinogenic insecticides. So even if someone did demonstrate a negative long term health impact of a GM crop, you would have to balance that out against a positive health impact.

    • Glenn says:

      Yes, great point. I have conducted long-term research on Bt cotton in India and I have seen reduced sprayings of some pretty nasty insecticides there (and published studies of it). It’s certainly plausible that this will have a positive health impact in the distant future.

      The problem is that we’ll never be able to measure it, given that a) there are a lot of different insecticides in use, with different modes of action, none of which have well known health impacts, and b) the situation is changing very quickly, with some signs that sprayings going back up, and c) even if we could identify a positive health impact for reduced sprayings we wouldn’t know how much credit to give Bt cotton since other factors affect insecticide use (check out Figure 3 in this article).

    • LFP says:

      That’s a common — and false — talking point of industry propagandists. As Glenn points out, pesticide use on some crops has gone down but overall herbicide use is way up. See .
      In fact, it’s likely that the reason GM technology was developed in the first place was to provide a new market and revenue stream for the herbicides that the company’s also conveniently sell. Capitalism 101.
      By the way the “crazy environmentalists” were correct on this issue. It’s Borlaug who looks like a fool in retrospect, contrary to what his army of scyophants continually tell us.

      • borderglider says:

        Pesticide use has NOT gone down as a result of mass GM plantings in the USA. The WEIGHT of pesticides may have been reduced but this is a smokescreen. Over 200 million acres of American corn (maize), soy, canola and cotton – plus orchard fruits and berry crops and almonds, are all routinely treated with neonicotinoid seed coatings – regardless of whether there is any ‘pest threat’ or not. In the past, pesticides were applied as a ‘reaction’ to a pest appearing; now they are used ‘prophylactically’ (as an insurance policy) on every seed, in every crop, in every field, year upon year.

        The main point however, is that these pesticides are a quantum leap in TOXICITY. Imidaclopird is 8,000 times more toxic to bees than was DDT; Clothianidin is 11,000 times more toxic than DDT (Bonmatin, Montpelier University, France 2013). So although far less WEIGHT of neonics is applied – the toxicity is massively greater. Dr Christian Krupke at Purdue University measured the lethality of neonics applied to A SINGLE GRAIN OF MAIZE at planting time; the 1.25mg used in ONE seed coating is sufficient to kill 50,000 honeybees. With corn planted at say 12,000 seeds to the acre, and 100 million acres planted across the USA, you can see why America has lost over 15 million bee colonies since 2003.

        An additional factor is ‘TOTAL TIME OF EXPOSURE/ TOXICITY’. In the past, pesticides sprayed as foliar sprays may have remained toxic for 4 days or a week before rain washed them away or UV light degraded them. But Neonics and Bt toxins are SYSTEMIC within the cellular structure of the plants; they remain lethal to bees for an entire season, not just a week or two. Moreoever, 90% of the neonics applied to a crop remain in the soil after the crop is harvested and Clothianidin can persist in soil for up to 7 years. So used every season you have a ‘hyper-persistent’ reservoir of systemic poison in the soil of every field over 200 million acres of America.

        The entire agricultural environment of America is now so poisonous to all forms of life that it is fast becoming an ecological desert. Neonics kill almost everything that crawls, flies or creeps through the soil: bees, butterflies, hoverflies, ladybugs, mantises, lacewings, beetles, bugs, earthworms etc. They truly are the poisonous gift that keeps on giving.

      • Glenn says:

        There are definitely grounds for real concern about neonics but I’m not sure how GM seeds would promote prophylactic spraying of neonics on the crops you mention. However, the 2 countries with widespread Bt cotton planting by smallholders (China and India) have seen rising numbers of sucking pests as Bt has spread. Those are the pests the farmers use neonics on. In India, the ads in the ag input shops changed from promoting organophosphates to promoting neonics. I have written on this in World Development.

  7. Márcia W. says:

    Thanks for this very informative article.
    I do not know if any research is being done in Brazil where DDT was officially banned only in 1998 ( After the introduction of GM crops use of pesticides here increased 162% (—14870.htm). A world record not to be proud of….

  8. John Cowan says:

    I would submit that the effects synthetic chemicals whether originating from industrial creation or radical genetic manipulation are unknown. Cancer or some other disease can only be associated with exposure to a substance but direct causation of some defined disease is very hard to establish. There are many factors and contexts to exposure that statistical studies do not account for. This leads to soft finger pointing at best.

    Humanity is partaking in an uncontrolled experiment. The environment is complex and variable. Those that declare something safe or unsafe don’t really understand how life operates. We are stirring the pot of life’s existence. Life will adapt or die. The interim will be a challenge for everyone. Policy makers are not going to deliberately influence something that they don’t understand. Of course, economic interests and academics will lead the way into the fog.

    • Glenn says:

      Of course you may be a bit partial to over-generalization. It’s difficult to say that “effects [of] synthetic chemicals” are unknown; some are known, some are very partially known, some and unknown. Some mechanisms are known, some partially known, some unknown. One of the most important aspects of good science is a clear understanding of the limitations of one’s data and explanatory models. There are many areas of science where the important interactions are very well understood; there are others where we are just beginning to get a handle on things. Economic interests can certainly cloud the picture, or create ignorance. With GMO’s one of the problems is the merging of economic interests and academics.

  9. John O'Brien says:

    After reading your article, Glenn, (but without knowing the possible early exposure to DDT) how very ironic to realize that Rachel Carson actually died of of breast cancer, which she attempted to hide from the “attack dog” press while she was taking her information public. I would like to submit that the major long-term effect of Borlaug’s pitbull non-objective ways was/is not defense of DDT, but the agribiz policy he instituted of fencerow to fencerow monoculture cropping. To this day it persists as emblematic of support for and defense of very profitable chemicals to the exclusion of concern for long-term consequences. I would also like to point out the hubris of defending use of these chemicals, these policies and focusing solely on potential target organism “homo sapiens” as the only subject for risk assessment to the exclusion of the rest of the biome. This is now brought to the forefront with the new questions raised by Senneff et al around the issue that to a large degree, glyphosate has been touted in non-scientific terms and approved as GRAS, because of the narrow thinking that glyphosate works on the Shikimate pathway, so it must be safe for humans because humans and other mammals do not have a Shikimate pathway. The colossal “whoops” is that 9 of 10 cells in our body which are are enterobiome, DO have a Shikimate pathway, and glyphosate’s adverse effects on human gut flora have NOT been adequately studied

    • Glenn says:

      Thanks — it indeed ironic, and it would have been more ironic if she had been exposed as a young girl, so that DDT could have been a factor in her developing breast cancer. But she would have been 38 when the spraying started, so highly unlikely DDT was a factor. But they sure did go after her, and they still do, blaming malaria deaths on her. (Of course the widespread overuse she described was in agriculture. Mosquito control was a much smaller use. The problem wasn’t vector control, it was industrial agriculture.)

      The microbiome is such a frontier of science. We don’t even know who all the players are, let alone how they change and interact and affect our health. The recent stuff on links between gut bacteria and autism is blowing my mind.

  10. With nearly twenty years of commercial GE crops and over three trillion meals consumed that contained ingredients derived from these crops, there is not one single documented case of harm attributed to these crops. More to the point there is not a single scientifically defensible hypothesis of how the current GE crops would represent a significant threat to people. These indisputable facts are why those who study this area of science are so confident in the relative safety of GE crops and derived foods ( there is no such thing as ‘risk-free’ anything)

  11. As for Brazil-China connection. One must also include Europe as they import millions of tonnes of GE crops from Brazil each year as well. In fact most of the world relies on GE crop for the animal agriculture industry.

  12. David Miller says:

    DDT was clearly overused in agricultural applications, but the banning of DDT has contributed to the death of millions of people from malaria and other mosquito-borne diseases. Yes, it has some negative environmental effects, but so do malaria-infested environs.

    • Glenn says:

      DDT is still used in many countries for vector control, and even in the US with special permits. But of course my blog wasn’t even about the pros and cons of vector control; it was about the science on DDT’s health impacts. Any attempts to weigh the costs and benefits of using DDT were worthless because we didn’t have any solid indications that DDT was harmful to humans until 2007. Nevertheless Borlaug and many industry hacks heaped ridicule and disdain on people who questioned its safety.

  13. Janneli Miller says:

    Great article and discussion. There is not only the hubris of our homo sapiens centric thinking, but that of believing we know something when we don’t- as the 62 year delay in discovering the impact of DDT on human health demonstrates. Science can help us understand the complexities, but at the very least, as food consumers, I think we need Informed Choice: to be able to choose whether or not we want to put these things in our bodies. Thus labelling GM foods is essential, and yet the corporations lobby hard not to allow this. Recent citizen led movements in several states to label GM foods have been defeated by Monsanto led campaigns promoting the “safety” of the GM foods and bashing the “hippie anti science environmentalists”. (Colorado an example). I also think it’s insightful (and a bid sad) that environmentalists are still being called “hippies” or “crazy” when they’re just calling for a modicum of caution. There is the “Precautionary Principle” after all- First do No Harm, etc etc, and whether or not consumers can decipher the science themselves still doesn’t mean that they should be guinea pigs for profiteers.
    Thanks so much for this Glenn

  14. jskirk88 says:

    This is so bizarre, I just posted something similar on Facebook:

    > One of the propaganda mantras regarding “proof” that GMOs are safe is actually based on absence of “proof” that “after twenty years, there are no known health issues.”

    The absence of proof is not positive proof that the opposite is true: This is called pseudoscience.

    When they declare that they are safe because there is an absence of proof (which there is not), the only conclusion one can draw from such an observation is that what they are really saying is:

    >> “we aren’t aware of any such things, and we don’t want to be aware them either.”<<<

    Again, this is pseudoscience. They are making a conclusion that GMOs are safe to eat based on a lack information, not an overwhelming amount of information that supports this assertion.

    One of the problems with this is that this conclusion is based on the choice not to examine proof to the contrary, or if they do examine such proof, they automatically dismiss it because for whatever illogical reasons, they declare it is not credible. This false assertion that all information, opinions, and studies that do not in any way support the pro-GMO agenda are invalid is not a valid argument and is contrary to scientific methodologies. It is just another propaganda/disinformation tactic, it is anti-science.

    Since there are no examples of peer reviewed, double blind, controlled studies done on humans, over a period of years, to determine whether or not any or all GMOs are intrinsically safe, making an assertion that they are safe without such evidence is absurd. No such studies have ever been conducted.

    Anyone who declares that all GMO foods now, and in the past, and in the future are, or were, or will be, intrinsically safe, is either invested financially in the biotech industry in some way, or just plain stupid.

    It's like saying, all medications from the pharmaceutical companies in the past, now, and in the future have always been, are, or will be safe.

    It is anti-science. It is illogical. Making any assumption like that is foolish, ridiculous, insane, stupid, ridiculous, a defiance of the laws of reality and logic, it makes no sense.

    If the assertion that all GMOs are intrinsically safe were true, then there would never have been a recall of StarLink corn, which was never approved for human consumption because it contained an allergen. To make matters even worse, the StarLink crops cross contaminated other non-GMO corn crops – another major potential source of harm which the pro-GMO advocates initially denied would ever happen, and in the face of repeated evidence to the contrary, they have begun to spin the message differently by talking about the need for "co-existence," another fabrication built on a false premise. The StarLink Cry9C allergen and the cross contamination issue caused a multitude of problems – to the extent that for well over 7 years after the product was withdrawn from agriculture, the USDA monitored all corn crops (and probably, insufficiently).

    And then there was Bt10, which ended up having a gene that conferred resistance to the antibiotic ampicillin. How safe can that be? Good thing it was withdrawn as soon as it was discovered.

    If they are intrinsically safe, why do the safety efficacies of other GMO brands remain a concern? If the science is perfect, why are there other failures as well? And why is this topic suppressed, and not publicized as widely as the myth that GMOs are intrinsically safe?

    Besides Star Link Cry9C and Bt10, there are others, among them:

    NK603 GE; MON 87460; MON810; MON 863; MON 88017; DAS-59122-7; The Flvr Flav tomato; CR3-623; Bt176; GNA-GM; MON89034; DAS1507; and DAS59122, and so on.

    For every quote from every "expert" or front group that says that GMOs are intrinsically safe, there are more quotes on why that is not only untrue, but pure foolishness as well. Such erroneous statements from the industry or supporters of the industry are essentially meaningless and without merit.

    It is pseudoscience. It is magical thinking. This claim of safety rests on this premise as well:

    "If one GMO product is safe, it therefore follows that all GMO products will also be safe in the future."

    That is essentially what every single one of those front groups or biotech spokesman is saying. That's not science. That's B.S.

    The notion that GMOs are "substantially equivalent" to their non-GMO counterparts is also ridiculous. It is only based on nutritional content, not safety, and there is now evidence that even the nutritional content of at least some GMO foods is less than the non-GMO counterparts.

    The policy of substantial equivalence was adopted by the FDA in 1992, and they have never reviewed or revised it. That too, is a form of insanity. It is based on a lack of information, misinformation and a general lack of knowledge of genetic engineering when any GMO food products are applied in agricultural conditions. It is also a policy that is based on a a group of individuals who were totally biased in every way in favor of genetically modified foods. The policy only enables the FDA to examine data from a lab, not the real-world application of those products.

    There are no required studies after any GMO products have been introduced in agriculture, no required independent follow-up studies about pesticide use, or environmental impacts, or anything else.

    Another myth that is perpetuated by certain people and groups has to do with "well, those companies spend years testing those genetically modified products."

    First, if this is true, (and why should anyone blindly believe this to be true when for decades, for example, Monsanto said for years PCBs were safe), then, why all the problems?

    And, why aren't those "years and years of safety studies" that are allegedly done prior to the application for FDA approval, ever published first in peer-reviewed journals – and then why are those studies not repeated by independent groups prior to that approval? Why is that?

    Who is in charge of testing each GMO food for safety – on an individual basis – before FDA approval?

    "Monsanto should not have to vouchsafe the safety of biotech food. Our interest is in selling as much of it as possible. Assuring its safety is the FDA’s job." — Philip Angell, Monsanto's director of corporate communications, “Playing God in the Garden”, New York Times Magazine, 25 October 1998

    "Ultimately, it is the food producer who is responsible for assuring safety." — US Food and Drug Administration (FDA), “Statement of Policy: Foods Derived from New Plant Varieties” (GMO Policy), Federal Register, Vol. 57, No. 104, 1992, p. 229

  15. Foster Boondoggle says:

    GE is not some mysterious substance that certain crops are imbued with, which seems to be how you’re characterizing it. (Though there’s not an “it” – there’s a whole range of “those”.) And it’s certainly less random than chemical or radiation mutagenesis, which as you know well entails no testing whatsoever (other than the market test of “do farmers want it”) prior to release – certainly no tests of human or environmental safety. In fact at my local produce store I can get certified Organic Rio Star grapefruits created this way. Why the double standard?

    But more to the point: we *know* what’s different about HT corn and soy. They contain an extra enzyme. We *know* what’s different about Bt corn and cotton: they contain a new protein (very similar to one Organic growers are very fond of spraying on their crops). We *know* what’s in VR papaya: an extra bit of DNA that gets transcribed so as to block production of a viral protein. And so on. In each case, there’s a tiny stretch of DNA and there’s its product. We consume all sorts of DNA with every meal. Is there some reason why we need to be especially worried about this DNA? Likewise, we consume a large variety of proteins with every meal, almost all of them never tested, at all, for potential harm. Our bodies are quite expert at disassembling them to amino acids. The GE ones are at least tested for allergenicity. Is there some reason why we should be concerned about these particular ones? If not, then please explain why we should be so very concerned about consuming GE ones and not all the others that exist in our food.

    Your argument here seems to prove far too much: it proves that *everything* we eat *could* be bad for us in subtle and alarming ways. After all, if it was that difficult to detect the harm of DDT, who knows what harms lurk in ordinary tomatoes, potatoes, cantaloupes, turmeric, oregano, basil, etc., etc., none of which have ever been tested in the manner you’ve described, and all of which are full of all sorts of far more distinct and unique compounds than merely DNA and protein.

    • Glenn says:

      I quit reading after “mysterious substance” — I said nothing of the sort.

      • Foster Boondoggle says:

        “some effects of highly processed ingredients made from GM plants may be “beyond the capacity of science to find.””

        Sounds pretty mysterious to me. Is this like homeopathy where undetectable things cause the greatest effect?

        But here’s the real point that you chose to skip over: Your argument here proves far too much: it shows that *everything* we eat *could* be bad for us in subtle and alarming ways. After all, if it was that difficult to detect the harm of DDT, who knows what harms lurk in ordinary tomatoes, potatoes, cantaloupes, turmeric, oregano, basil, etc., etc., none of which have ever been tested in the manner you’ve described, and all of which are full of all sorts of far more distinct and unique compounds than merely the altered DNA and minimal new proteins of the GMOs commercialized to date.

        And anticipating one of the other claims commonly made about why ordinary things we eat don’t need testing: we didn’t “co-evolve” with any of these. Tomatoes and potatoes, for example, were unfamiliar to old-world humans’ bodies until 500 years ago.

    • Belinda says:

      GE, as currently practiced, is actually a very “random” process in at least one respect. Some 30-60% of the time the “known” bit of DNA inserted into a crop plant lands in a protein-coding gene, mutating that gene. And who knows what important process might be disrupted when that bit of DNA lands elsewhere in a plant’s genome…because our current understanding of the 95+% of plant genomes that do not code for proteins is primitive at best. The Agrobacterium method of inserting genes into plants is, in fact, such a good mutagen that scientists have used it to mutate (and “tag”) most of the protein-coding genes in Arabidopsis (a model plant organism used for research).
      Even the FDA admits that unintended, unexpected effects can result from GE…and this phenomenon of insertional mutagenesis is one of the sources for such effects.
      These unintended, unexpected effects are what researchers are looking for when they conduct animal feeding studies with GMOs. But whenever a scientific study suggests that a GE ag product may be exhibiting unintended deleterious effects, plant molecular biologists call for the study’s retraction instead of for more science to corroborate or refute the study’s results! That’s not science…that’s shameful!
      GE is not as precise a technology as you have been led to believe. On a good day, even its proponents will admit that its products should be regulated on a case-by-case basis.
      And regulation of GE crops/foods in the US is not as strict as you may have been led to believe either. It is currently possible to design a GE crop that would require no pre-market regulation with EPA, USDA or FDA.
      We need more science on GE products (not attacks on science by scientists with conflicts of interest), we need better pre-market regulation of them and, because we don’t understand genomes enough to be able to identify all the unintended, unexpected effects that randomly inserting “bits” of even “known” DNA might cause, GE foods should be labeled in grocery stores so that American citizens can vote for, or against, them with their pocketbooks.

      • Glenn says:

        And regulation of GE crops/foods in the US is not as strict as you may have been led to believe either. It is currently possible to design a GE crop that would require no pre-market regulation with EPA, USDA or FDA.

        A recent example being Scott’s Roundup-Ready bentgrass, subject of a pithy earlier blog. No FDA oversight (it’s not a food!), no EPA oversight (no Bt!) and no USDA oversight (no agrobacterium!). “Over regulated”? Over what?

      • In a recent discussion of harmful traits developed by conventional breeding someone mentioned Tifton85 which killed a herd of cattle by prussic acid poisoning in Texas a couple years ago. The media originally reported this as a GE bermudagrass but eventually corrected their reports.

        GMO opponents were gleeful at first and seized on the initial reports as proof of harm. And when the truth came out? Crickets. No one demands accountability for the dangerous trait because the genetic fallacy rules: traits are bad if made with genetic engineering, but safe if made with conventional breeding. The actual risks to human health from eating cattle that might have been grazing on grasses with cyanogenic compounds isn’t relevant once it can’t be used to justify further testing and labeling the products of conventional breeding.

        I don’t blame conventional breeding for that trait. It’s a known hazard in certain circumstances and the Tifton85 breeders even looked for the possibility of prussic acid but didn’t find it. However, no one would have guaranteed this. They looked because it’s a known hazard in related breeds. The rancher didn’t follow best practices that exist because this is a possibility, and ultimately the cause of death is best attributed to his error.

        But you know this argument about the environment and best practices not followed holds no sway once a person decides that GMOness was the cause. It could have been a GE bermudagrass where it behaved in the exact same way, for the same reasons, but exculpation would be impossible.

        There’s a chance some day that we can better identify and silence genes that responds to drought stress by making cyanogens. The potential to make food safer this way is lost on opponents.

  16. mkessy says:

    Excellent article.

    I’m curious what your thoughts are on this Slate article that has created quite a splash:

    Having read much of your work on Ag/GMOs, I think the article demonstrates many of the faults of the current debate. The explicit framing of anti-GMO as anti-science is particularly detrimental, only working to further polarize, as the team on the side of science need no longer listen to the loud “anti-science leftists.” The article does well to dispel the myth-making about ‘frankenfoods’ that is prevalent in the ‘anti’ crowd yet offers no such treatment to the (arguably more pernicious) myth-making on the other side. Also absent is any substantive discussion of GMOs as they exist in the larger political economy of industrial agriculture or alternatives such as agroecology. To me this article demonstrates a certain arrogance if you will, one that I haven’t fully been able to comprehend, wherein a genuine interest in finding out the truth is corrupted by a vehement desire to prove one side as wrong, stupid, and against the venerable institutions of capital S “Science.” I also have a feeling that the social sciences are rarely if ever used as an informer to these types of articles.

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  18. TBest32 says:

    Very interesting. You caught me off guard there.

  19. Mike Myhre says:

    Not labeled so we can claim cause-effect when found. Exempt from prosecution by the government should any evidence be found. Not tested by the FDA. Not willing to tell people it is GMO. So many wrongs and no recourse when they get caught. I don’t want to be part of your experiment and I am a scientist.

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  21. Michael Marshall says:

    So what you have is (assuming no flaws in the studies) an interesting correlation, but no smoking gun mode of action to definitely show DDT exposure alone is the culprit here. Then you use this correlation as if DDT has in fact been shown to cause breast cancer as an example of the dangers of assuming a chemical exposure long seen to be without harm really isn’t harmless.

    Where to start?

    As I’m sure you know, correlations don’t prove cause and effect, and the structure and chemistry of DDT has almost no physical or chemical similarity to the proteins affected by genetic engineering. So what you really end up with is a seeming alarming analogy that falls apart under even a cursory examination.

    It may well be that GMO proponents, such as myself, seem a bit too ready to accept the “harmless” label for GMOs, but one of the contributing factors is surely the constant stream of poorly thought out exaggerated postulates of potential harm such as this one that we are just tired of responding to. You come up with a “smoking gun,” then by all means let the world know, but until then please quit trying to cobble together these poorly thought out far-fetched hypothetical “maybes” that stretch credulity and require poor reasoning skills to accept. Have a nice day.

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