Genetically modified organisms (GMOs or GMs) are one of the most well studied areas of biological and agricultural research. However, one of the tactics of the GMO refusers is that “there’s no proof that GMOs are safe.” It’s time to look at the GMO science facts – examining myth from science.
Typically, in a debate, the side making the assertion (those that say GMOs are unsafe) are responsible for the evidence that supports their contention. But, the anti-GMO gang relies upon the argument from ignorance, trying to force the argument to “if you can’t prove that they’re safe, they must be unsafe.”
The anti-GMO forces also like to invoke the precautionary principle, which attempts to shift the burden of proof to those who are advocating GMOs (or any new technology) until the advocates “prove” that there are absolutely no negative consequences of using GMOs.
The principle is often cited by anti-science and/or environmental activists when there is a perceived lack of evidence showing that a technology is absolutely safe.
I’ve written numerous articles about GMOs, focusing on scientific evidence supported by high quality research. And more than a few articles debunked myths and bad research from the anti-GMO crowd. To assist those who are doing research on the topic, this article was created to be a one-stop shop for GMO science facts – and fiction.
People love their bananas, one of the most popular fruits consumed in the world. We generally only eat one banana cultivar, the Cavendish, which replaced another cultivar that was susceptible to Panama disease, a type of Fusarium wilt. Unfortunately, the Cavendish banana has been devastated by a new form of that fungal disease which might lead to the end of the availability of the banana in your local grocery store. But there is hope – scientists are developing GMO bananas that may save the fruit from becoming a distant memory.
Let’s wrap our mind around that – genetically modified gluten. I’m sure that won’t be problematic for those who have medically diagnosed issues with gluten. They’re going to be thrilled that they can eat real bread, pizza or pasta. I’m sure they’re not going to be concerned with any label that says “GMO foods here.”
On the other hand, I’m certain (but I have no scientific evidence) that the Venn diagrams of those who buy into the nonsense about GMOs also buy into the pseudoscience of gluten. Those people might fall over from confusion.
If you cruise around the internet, engaging with the antivaccination cult (not recommended), you will pick up on their standard tropes, lies, and other anti-science commentary. One that has always bothered me, not because that it was a lie, but because I had enough evidence floating in my brain that I was wondering if it were true–that vaccines cause diabetes, especially the Type 1 version.
In another example of the antivaccination world’s cherry picking evidence to support their a priori conclusions, they ignore the utter lack of plausibility supporting any link between vaccines and Type 1 diabetes.
Moreover, Classen seems to come to his beliefs based on population-wide correlations that rely on post hoc fallacies, rather than actually showing causality between vaccines and diabetes. It’s like finding that a 5% increase in consumption of Big Macs is correlated with Republican wins in elections. They may happen at the same time, but it would take a laughable series events to show any relationship.
The IARC, one of the intergovernmental agencies within the World Health Organization, is widely respected for their research into the causes of cancer. And with respect to glyphosate, the IARC concluded that:
There was limited evidence in humans for the carcinogenicity of glyphosate. Case-control studies of occupational exposure in the USA, Canada, and Sweden reported increased risks for non-Hodgkin lymphoma that persisted after adjustment for other pesticides.
The AHS cohort did not show a signifi cantly increased risk of non-Hodgkin lymphoma. In male CD-1 mice, glyphosate induced a positive trend in the incidence of a rare tumour, renal tubule carcinoma.
A second study reported a positive trend for haemangiosarcoma in male mice. Glyphosate increased pancreatic islet-cell adenoma in male rats in two studies. A glyphosate formulation promoted skin tumours in an initiation-promotion study in mice. Glyphosate has been detected in the blood and urine of agricultural workers, indicating absorption.
Glyphosate and glyphosate formulations induced DNA and chromosomal damage in mammals, and in human and animal cells in vitro. One study reported increases in blood markers of chromosomal damage (micronuclei) in residents of several communities after spraying of glyphosate formulations.
The Working Group classified glyphosate as “probably carcinogenic to humans” (Group 2A).
Unfortunately, when the IARC made its decision two years ago, there was one major problem. According to an extensive article by Kate Kelland in Reuters, one of the members of the IARC’s study group looking at glyphosate knew of recently published data that showed no link between the weed killer and cancer. Aaron Blair, an epidemiologist from the US National Cancer Institute, never mentioned this new data to the study group examining whether glyphosate causes cancer. So the IARC made its decision without all of the available evidence.
Reuters obtained information that lead it to state that:
Previously unreported court documents reviewed by Reuters from an ongoing U.S. legal case against Monsanto show that Blair knew the unpublished research found no evidence of a link between glyphosate and cancer. In a sworn deposition given in March this year in connection with the case, Blair also said the data would have altered IARC’s analysis. He said it would have made it less likely that glyphosate would meet the agency’s criteria for being classed as “probably carcinogenic.”
The IARC acts in a manner that it appears to develop a scientific consensus about what may increase the risks of cancer. As I have mentioned many times, the scientific consensus is a powerful tool in providing us with the collective conclusions of top scientists in a field. However, this consensus must be based on evidence, not opinion or belief. And if a consensus is “proclaimed” without consideration of all of the high quality evidence, then it’s hard to put much value in it.
Now there wasn’t a grand conspiracy that blocked the IARC from considering this new evidence. Blair himself was a senior researcher on the study that showed no link between cancer and glyphosate. The reason the research wasn’t included was simple – the IARC only uses published data to come to its consensus about cancer risk, and Blair’s research could not be included in the discussion. This leads to increased transparency and reduces the risk of claims of “secret evidence” that may lead to accusations of bias.
Now, this rule may seem onerous to some, it does keep the discussion to peer-reviewed data, ignoring data that hasn’t been vetted. This probably works both ways, leaving out data that may move a chemical into a cancer causing category or not.
But this decision by the IARC had some significant consequences. First, it’s hard to read anything about GMO foods, agriculture, or food without someone spouting off that “glyphosate causes cancer.” In fact, there’s a class action lawsuit in California, with 184 individual plaintiffs, who use the IARC analysis on glyphosate, claiming that exposure to the chemical gave them cancer. The plaintiffs allege Monsanto failed to warn consumers of the risks of RoundUp, which Monsanto fiercely denies.
Monsanto claims that the fresh data should have been published in time for use in IARC deliberations on glyphosate. Or, at the minimum, the preliminary data should have been evaluated, considering Blair’s involvement with both the IARC and the new research.
Again, according to Reuters,
The company also goes beyond saying the fresh data should have been published. It told Reuters the data was deliberately concealed by Blair, but provided no specific evidence of it being hidden.
So this gets a bit more troubling.
What did Aaron Blair do? And why?
This is what is troubling to me. Actually, the data that mostly refuted the hypothesis that glyphosate causes cancer was available two years before the IARC assessment meeting. Now, science does move slowly, but that’s glacial.
According to Blair, the data was not published in a timely manner because there was too much data to fit into one scientific paper (which seems like a lame excuse to this writer). Reuters actually asked whether “he deliberately did not publish it to avoid it being considered by IARC.” Of course, Blair denied it. Furthermore, the National Cancer Institute also stated that “space constraints” was one of the reasons why the new data on glyphosate was not published in a timely manner.
Of course, the absence of Blair’s data was a critical oversight – the IARC ended the meeting by concluding that the weed killer is a “probably human carcinogen.”
In fact, the statement based its findings on “limited evidence” of carcinogenicity in humans, but “sufficient evidence” in animal research models. It specifically stated that there was a “positive association” between glyphosate and non-Hodgkin lymphoma, a cancer of the blood.
Beyond the litigation mentioned above, the IARC had all kinds of negative consequences. For example, some countries have pending decisions regarding whether to relicense or ban sales of glyphosate. Some countries have even restricted glyphosate’s use in home gardens and on crops immediately prior to harvest.
And back to the class action lawsuit in California, Reuters reports that:
… (the) California judge took the IARC assessment into account in a separate legal case in March when ruling that the state can require RoundUp to carry a warning label that it may cause cancer. Monsanto is now facing further litigation from hundreds of plaintiffs across the United States who say glyphosate gave them or their loved ones non-Hodgkin lymphoma, citing the IARC assessment as part of their claims.
All, because of an apparently flawed decision without all of the high quality evidence considered. This is frustrating from a scientific standpoint.
What is in Blair’s study?
This unpublished research, and it’s still unpublished, came from the Agricultural Health Study, a large multi-center study led by scientists at the National Cancer Institute. The researchers examined agricultural workers and their families, in the USA, who were exposed to various agricultural chemicals, including glyphosate. Blair himself agreed that the unpublished data showed “no evidence of an association” between exposure to glyphosate and non-Hodgkin lymphoma.
In fact, a review by Acquavella et al., published in 2016, examined the body of research regarding glyphosate and non-Hodgkin lymphoma. The authors concluded that, “overall, our review did not find support in the epidemiologic literature for a causal association between glyphosate and non-Hodgkin lymphoma or multiple myeloma.” That’s a pretty powerful finding with regards to the IARC decision.
Additionally, Robert Tarone also published a paper in 2016 that took IARC’s decision regarding glyphosate to task. He concluded that,
It is shown that the classification of glyphosate as a probable human carcinogen was the result of a flawed and incomplete summary of the experimental evidence evaluated by the Working Group. Rational and effective cancer prevention activities depend on scientifically sound and unbiased assessments of the carcinogenic potential of suspected agents. Implications of the erroneous classification of glyphosate with respect to the IARC Monograph Working Group deliberative process are discussed.
The IARC’s decision that glyphosate causes cancer seems to be under attack by serious researchers.
Blair admitted, while being deposed by Monsanto lawyers, that IARC’s review of whether glyphosate causes cancer would have been different if the Agricultural Health Study data were included. According to Blair, the addition of the missing data would have “driven the meta-relative risk downward.” In non-scientific terms, that means meta-data would have shown a reduced correlation between glyphosate and non-Hodgkin lymphoma.
Essentially, the IARC review ignored a huge body of robust data from a comprehensive study on exposure to glyphosate, and it’s relationship to cancers. This is a major oversight of the IARC decision.
And it’s just shocking to note that one person, Aaron Blair, was on the IARC review committee and had insider access to high quality data that refuted the IARC’s claims of correlation (and causation) between glyphosate and cancer.
Reuters took the data (which, as I stated, still has not been published, although the NCI told Reuters that they are currently working on an updated analysis) to two statistical experts to determine what it may say about whether glyphosate causes cancer. Neither of the experts had seen the data, and neither had a conflict of interest with respect to glyphosate or Monsanto.
The experts came to two key conclusions after examining the data:
There was “no apparent scientific preseason for not publishing the data” from the large study. In other words, absent some issue like bias or bad study design, they felt that the data was publishable in its current form.
The data shows no evidence that glyphosate causes cancer, especially non-Hodgkins lymphoma.
Of course, you’d think that the IARC would reconsider it’s decision about glyphosate, relying upon all the science, not just what they had already decided. Apparently, that’s not going to happen.
Reuters wrote to the IARC about Blair’s new data and whether they would reconsider their position. They responded by email,
IARC declined to say whether Blair informed IARC staff about the unpublished data, whether he should have, and whether that data might have changed IARC’s evaluation of glyphosate had it been published in time. The agency said it had no plans to reconsider its assessment of the chemical.
That’s not very scientific. The consensus must change with new, high quality data. It seems like the IARC is being stubborn about their decision rather than looking at more robust evidence that contradicts their conclusions.
Glyphosate causes cancer – the Summary
As I wrote in 2015, without the data from the Agricultural Health study, I, and other researchers, felt that the IARC decision was suspect. It seemed to rely upon very weak associations between glyphosate and non-Hodgkin lymphoma, while ignoring high quality evidence that showed no correlation.
With this data, as yet unpublished, the IARC’s decision about the carcinogenicity of glyphosate just doesn’t pass scientific credibility.
I hope that when Blair’s study finally gets published, the IARC will review its findings and follow the science to a more defensible conclusion. What should trouble the IARC is that many scientists are starting to look askance at their decisions regarding carcinogens. The evidence just doesn’t support their conclusions on glyphosate, but what if their decisions about other chemicals is also this badly done?
Chemistry is important. If you’re going to make negative claims about GMO sugar or high fructose corn syrup, we ought to be able to look at these different sugar molecules and confirm a difference between them. So let’s take a look at sugar from three different sources that capture our attention. Sorry, but there will be a quiz afterwards, so please pay attention.
A. GMO sugar after consuming it
B. Natural sugar after consuming it
C. High fructose corn syrup GMO sugar after consuming it
In the hierarchy of scientific principles, the scientific consensus – that is, the collective opinion and judgement of scientific experts in a particular field – is an important method to separate real scientific thought from junk science, pseudoscience, cargo cult science, and other fake beliefs.
I often discuss scientific theories which “are large bodies of work that are a culmination or a composite of the products of many contributors over time and are substantiated by vast bodies of converging evidence. They unify and synchronize the scientific community’s view and approach to a particular scientific field.”
A scientific theory is not a wild and arbitrary guess, but it is built upon a foundation of scientific knowledge that itself is based on evidence accumulated from data that resulted from scientific experimentation. Generally, a scientific consensus eventually leads to a scientific theory.
There are constant claims made about GMO food safety – everything, from causing allergies to causing cancer. Taking lessons from the anti-vaccine world, anti-GMO activists invent, based on very little or even no evidence, various claims about GMO food safety. One of the worst of these claims is that when you eat GMO foods, the genes from the food somehow, by magic apparently, get incorporated into your genes.
Unfortunately, like the zombie bad research on vaccines, a widely criticized article that seems to claim that DNA passes from GMO foods to humans continues to be an anti-GMO meme. Time to look at the article again, and see if gene transfer really is an issue to GMO food safety.
GMO food safety – the gene transfer paper
In a paper published in the online journal, PLoS One, the authors, Spisak et al., seem to indicate that there is a possibility that DNA fragments pass from the digestive tract into the blood. The authors concluded that:
…based on the analysis of over 1000 human samples from four independent studies, we report evidence that meal-derived DNA fragments which are large enough to carry complete genes can avoid degradation and through an unknown mechanism enter the human circulation system.
The authors admit that the mechanism is unknown, though it’s curious that years of study of the molecular transport of nutrients has never uncovered this until 2013. Based on this limited evidence, here’s what the anti-GMO crowd says about it:
What biotechnology and biotech corporations like Monsanto have done, is they have allowed for the transfer of genes from one to the other without any regard for the biological limitations, or constraints.
The problem with this is that it is based on very bad science. The conditions and biological ‘rules’ that apply to vertical gene transfer, at least those that we are aware of, do not necessarily apply to horizontal gene transfer.
Biotech science today is based on the assumption that the principles governing the inheritance of genes are the same when we move genes horizontally as they are when they are moved vertically. It just goes to show that GMO’s should be subjected to much more experimentation and rigorous research before we continue to consume them.
The paper’s conclusions were criticized by other scientists who are experts in DNA research. Moreover, there are some meta-level criticisms that can be made of this paper.
Speaking of repeating this research, in the four years since this paper was published, only six papers have cited it, two of which criticized the quality of research. If this were truly groundbreaking research, we would see many more papers citing it, along with some research that repeats it.
The study was published in an, open access, online journal, PLoS One, which has the publication philosophy of “publish first, judge later.” Well, we’re judging now.
The study examine minuscule levels of DNA in blood, nanogram levels. We definitely are able to detect nanogram levels of DNA, but at that low level, substantial risk of contamination is so high, that if one were to see these results, the initial hypothesis would probably be “this blood sample was contaminated,” rather than the infinitely more complex and undiscovered mechanism to move these huge molecules into the blood.
In fact, Richard W Lusk of the University of Michigan, spent six months reviewing the data and methods of Spisak et al. and concluded that they must consider contamination as the source of plant DNA. Lusk stated that contamination can account for these results, because DNA measurement is so sensitive, that even washed laboratory equipment harbors DNA fragments.
In a review of the papers by Spisak et al. and Lusk, it was concluded that “Poor commentary and cherry-picking data helps no one. Spisak’s study tells us about a significant biological finding that needs to be carefully analysed. The cautionary tale is that one must not extrapolate wildly from good science to create horrific scenarios that are not based on any scientific observations whatsoever.” In other words, even if Spisak’s results were not affected by potential contamination, we still could not conclude that GMO food safety is impacted by this data. And given that it hasn’t been repeated, and we have firm evidence that there was contamination, this paper probably should not be used to evaluate GMO food safety.
Based on our knowledge of the digestive process, fats, DNA, carbohydrates, and proteins are broken down into their simplest components, and specialized transport systems move these simple components across the barrier between the digestive tract and blood. Our digestive system has evolved to actually exclude full size bio-molecules, partially because the blood is incapable of carrying large foreign molecules (and could induce an immune response). So, a full chain of DNA isn’t going to move from the digestive tract to the blood, just individual nucleic acids. And just to be clear, nucleic acids are the same across every single organism on this planet. Exactly the same.
Moreover, small constituent molecules, like amino acids instead of the whole protein, or glucose instead of a long-chain carbohydrate, are more easily transported to locations in the body to be then used as fuel or building blocks for new proteins and DNA. We just have not seen a mechanism in the digestive tract that can move large molecules, like gene-length DNA fragments, into the bloodstream.
But let’s assume that there’s some unknown, mysterious mechanism that allows DNA to be transmitted into the blood (while excluding long chain carbohydrates, whole proteins, and other large molecules). The numbers are so small, just a handful complete genes, that the probability that those DNA molecules will have any effect on the body is near 0.
Genes don’t easily jump from one species to another. If gene transfer were so simple, the medical usefulness of gene therapy would be extremely high, instead of being incredibly difficult, if not impossible. We’re trying to transfer genes to cure diseases, and researchers have not shown a lot of consistent success. If consuming a few kernels of corn, introduced some gene into the bloodstream that somehow gets incorporated into the human genome, well that would be a miracle. But reality is, even if the article is accurate, and there’s doubt to that, it has little clinical meaning.
But the most important thing is that if there is some heretofore mysterious mechanism to transfer DNA from the digestive tract to the human genome, it should be noted that nearly everything we consume contains DNA. The plausibility that any number of DNA fragments from hamburger, salads, cereal, eggs, or the billion other foods will eat getting into the bloodstream is nearly non-existent. There is no evidence that we ever incorporate genes from corn. Or lettuce. Or a cow. Or a chicken. There is just no evidence of it.
It’s not just that Spisak et al. represents faulty research, but it’s hard to comprehend how it’s even possible that DNA could be in a state that could allow it to be transported into some random cell of the body. This type of misuse of science is frustrating – anti-GMO radicals cherry pick research that seems to support their point of view, but fail to understand biology and physiology. Of course, this happens all the time with anti-science activists.
Summary, the TL;DR version
I don’t know if the study in PLoS One is going to stand the test of time given the high probability of contamination of the study samples, which has been demonstrated by another researcher. After four years, there’s just no further research that supports it, something that makes me think it’s a one-off study of marginal utility.
But even if it is confirmed by other research or becomes the initial observation that leads to the discovery of a novel, and implausible, mechanism of transport of nutrients and gene transfer, it provides NO evidence whatsoever that GMOs are dangerous because those genes will be incorporated into our human genome. GMO food safety concerns are unchanged because of this research.
You may as well become worried that we’ll turn into a chicken after eating an egg. Oh no. Franken-foods might cause franken-humans. And because…Monsanto.
Real science is hard. It takes lots of high quality evidence to support it. That evidence needs to be published in real journal. It needs to be repeated. And it has to be open to criticism and analysis. GMO science, the study of genetically modified organisms used for crops and food, shows us that GMOs are safe.
The hard work and intellectual challenges to form a scientific consensus about the safety of GMO crops and foods isn’t something that appeared out of the ether. These individuals didn’t suddenly wake up one day and proclaim from the ivory tower that GMO science says that GMOs are safe. Not even close.
Like I said in another article, “The typical pseudoscientist will use logical fallacies to state very definitively that “it’s proven.” It’s the same whether it’s creationism (the belief that some magical being created the world some small number of years ago), alternative medicine (homeopathy, which is nothing but water, has magical properties to cure everything from cancer to male pattern baldness), or vaccine denialists. The worst problem is that in the world of the internet, if you Google these beliefs, the number of websites and hits that seem to state that they are THE TRUTH™ overwhelm those that are more skeptical or critical.”
So, using an open, but critical mind, the evidence is overwhelming – the GMO science says it’s safe for human consumption.
A scientific consensus is one of the most powerful principles in science, sitting just below the predictive power of a scientific theory. In general, a scientific consensus is the collective opinion and judgement of scientists in a particular field of study. This consensus implies general agreement, and disagreement is limited (sometimes from individuals who are not experts in the field) and considered insignificant.
This lead me to a search for the prevailing scientific consensus on GMO safety and climate change.
For clarity, the major difference between a scientific theory and a scientific consensus is that a theory is essentially considered a fact. The theory of gravity is a fact. The theory of evolution is a fact. A theory is so predictive, it is supported by so much evidence, and it is so well accepted, it would take an incredible amount of data to refute it.
The only thing that matters in forming a scientific consensus or theory is evidence. Not rhetoric. Not debate. Not opinion. Not political expediency. Not logical fallacies. Just evidence.
I’ve written about the scientific consensus on GMOs, and it is clear that nearly every independent scientific organization across the world agrees that GMOs are safe for humans and/or the environment. Moreover, most of these same organizations provide a similar consensus about climate change–ironically, there is a significant portion of people who deny one consensus but accept the other, despite the fact that the consensus for both scientific principles are based on nearly overwhelming evidence.
On the next page, I will review the statements of seven prestigious scientific organizations across the world for the scientific consensus on GMO safety and on climate change.