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Wednesday, December 04, 2013

Is there any reliable scientific evidence that genetically modified food poses a health risk?

I recently had a discussion about the safety of food derived from genetically modified organisms. My opponent, whose identity I will conceal (hi Rachel!), argued that GM foods are unsafe and that there's scientific evidence to back this up. Naturally, this evidence is being concealed by Monsanto and other private companies in the same way that tobacco companies tried to hide the evidence that smoking causes lung cancer.

My position is that I'm not aware of any reliable scientific studies showing that GM foods are dangerous to your health and, furthermore, in a free and open democracy with a free press it seems highly unlikely that such evidence is being suppressed. It seems even more unlikely that scientists would be part of this conspiracy.

I was aware of a paper published last year in Food and Chemical Toxicology. The authors were a group of scientists from France and Italy and the title looked ominous: Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize. I was also aware of the controversy surrounding this paper and I did not consider it "reliable." I tried to explain to my opponent that not everything that appears in the scientific literature is correct. In order to determine the scientific consensus on a subject like GM food, you have to read a lot of papers or ask the experts. You can't just cherry-pick the one or two papers that support your position.

A few weeks ago, I posted an article about the attempt to get GM food out of Girl Guide Cookies [19,853 People Can't Be Wrong ... Can They?]. This was a misguided campaign organized by a couple of women in La La Land British Columbia who claimed that GMO foods are not safe. They said that there was scientific evidence to support their claim.

At that time, I posted an update from an article I found: With 2000+ global studies confirming safety, GM foods among most analyzed subjects in science.
A popular weapon used by those critical of agricultural biotechnology is to claim that there has been little to no evaluation of the safety of GM crops and there is no scientific consensus on this issue.

Those claims are simply not true. Every major international science body in the world has reviewed multiple independent studies—in some cases numbering in the hundreds—in coming to the consensus conclusion that GMO crops are as safe or safer than conventional or organic foods, but the magnitude of the research has never been catalogued.

Still the claim that GMOs are “understudied”—the meme represented in the quotes highlighted at the beginning of this article—have become a staple of anti-GMO critics, especially activist journalists. In response to what they believed was an information gap, a team of Italian scientists catalogued and summarized 1783 studies about the safety and environmental impacts of GMO foods—a staggering number.

The researchers couldn’t find a single credible example demonstrating that GM foods pose any harm to humans or animals. “The scientific research conducted so far has not detected any significant hazards directly connected with the use of genetically engineered crops,” the scientists concluded.

The research review, published in Critical Reviews in Biotechnology in September, spanned only the last decade—from 2002 to 2012—which represents only about a third of the lifetime of GM technology.
There's plenty more where that came from [Good Food, Bad Food] [The Scientific Debate About GM Foods Is Over: They're Safe] [GMOs aren't the problem. Our industrial food system is] [A founder of the anti-GM food movement on how he got it wrong].

Now let's get back to that paper I referred to above. The journal is going to retract the paper because the data is unreliable [Controversial Seralini GMO-rats paper to be retracted]. You might think this will be a major blow to the anti-GM community but if that's what you think then you haven't been following the vaccine/autism controversy. In that case, retraction of the only paper supporting a connection between vaccines and autism just hardened the opposition.

You think that won't happen with the anti-GM community? Read: Ratted out: Scientific journal bows to Monsanto over anti-GMO study by William Engdahl. Here's what he says ....
The Journal of Food and Chemical Toxicology has apparently decided to violate those procedures, announcing it is retracting a long-term study on the toxic effects of Monsanto Genetically Modified Organisms (GMOs)—GMO Maize it published a year ago.

The bizarre reports come only six months after Elsevier created a special new position, Associate Editor for Biotechnology (i.e. GMO), and filled it with a former Monsanto employee who worked for the giant Monsanto front-organization, the International Life Sciences Institute, which develops industry-friendly risk assessment methods for GM foods and chemical food contaminants and inserts them into government regulations. Sound like something wrong with this picture?
This is a good lesson for my students. Remember that in today's world you have to have science on your side. You can pretend that science supports your position by cherry-picking the scientific literature or quoting scientists out of context. Or, you can claim that the topic is controversial and hasn't been resolved one way or the other. This is a way of negating uncomfortable scientific evidence that goes against your position. When all else fails, and the science is overwhelming against you, you have to fall back on conspiracies—scientists know the truth but they are hiding it from the general public.

It's the last resort and it generally means that you are about to lose the public debate.


  1. I would tend to think that GMO foods are safe, but admit I have spent very little time reading about the issue. I do recall, however, being surprised to read that some GMO organisms contain not just a single gene modification that produces new protein products, but also include activating factors that may have persistent effects.

    Am I misrembering or misinformed?

  2. I would argue that although the food products may be nutritionally similar and safe, it's the indirect effect of the overuse of roundup which poses a health risk. Contaminated run-off, weed resistance, and the consumption of herbicide make most GMO round-up ready plants a less healthy alternative to non-gmo plants that use crop rotation and timing schedules to mitigate the problem of weeds.

    In a lab setting it may be easy to conclude that the two types of plants are quite similar (ignoring long term effects of consumption of course as this can be very difficult to measure). However, it's possible that comparing things in a lab ignores the complete picture, not taking into account environmental and socio-economic impact, and indirect health risks.

    Science may be the best tool we have for safe-guarding us against possible risks such as this, but one should always take into account that science, in particular when in comes to matters of nutrition and health, doesn't always yield the perfect answer (in particular any company backed findings). For anything that we may ingest directly, it's possible that skeptism and caution are the best principles to follow. So aside from the risk factors mentioned above, if there's any doubt, or margin of error, perhaps opting for non-gmo foods is the best (and healthiest) idea.

    1. Let me give you a little lesson on how to argue about science.

      1. Roundup (glyphosate) is one of the safest chemicals known to humans. Millions of dollars and enormous amounts of time have been spent trying to find some way of proving that it poses a health risk. When you state or imply that glyphosate is harmful it weakens your case and makes you look like a kook.

      2, Weed resistance is a red herring. Farmers have been trying to get rid of weeds for centuries and nobody ever said they should stop doing it because the weeds are fighting back.

      3. When you raise the issue of "consumption of herbicide" you reveal that logic isn't one of your strong points. The whole idea behind Roundup-Ready crops is that farmers use LESS of the dangerous kinds of herbicide.

      4. The science shows conclusively that GM plants are not harmful to consumers. When you use silly excuses like "lab settings" and "long-term effects" you sound like a kook. I bet you don't use those arguments to avoid taking vitamin supplements or eating "healthy" foods even though they make just as much sense in those cases.

      5. When you say things like, " science ... doesn't always yield the perfect answer" we know you are a kook. I bet you don't say this when doctors prescribe antibiotics to cure your pneumonia.

      6. When you invoke conspiracy theories as a last resort ("in particular any company backed findings") then we know you have stepped outside science and rational thought because the definitive studies were done by academic scientists with no links to private corporations.

      7. When you claim that "skepticism and caution are the best principles to follow." we just laugh at you. We all know that you should keep and open mind but not so open that your brains fall out. The anti-GM crowd is notorious for its lack of skepticism. They are suckers for any anti-GM argument ever invented.

      8. Finally, when you say, "if there's any doubt, or margin of error, perhaps opting for non-gmo foods is the best (and healthiest) idea," we strongly suspect that you are a hypocrite. I bet you fall for all kinds of health food claims without giving a passing thought to doubts or margins of error.

    2. Larry, I know you worship science. I know you are in love with it. However, sometimes science gets is wrong at least once? Is that a reasonable argument? Is it possible that science can be wrong Sometimes?

    3. Science often gets things wrong. Fortunately, science makes claims which can be falsified. If Larry says "Roundup is safe", he doesn't mean it can be proved with absolute certainty. But it's a statement that could be refuted if experimental tests demostrated a health risk. Lots of experiments have been conducted and no evidence of risk has been found, so we can be reasonably certain there is no risk. The claim remains falsifiable. If you think a possible health hazard has been overlooked, design and carry out an experiment to show it, then publish your results. It's as simple as that.

    4. Really? Well, send me some links to the experiments YOU have conducted and the results you have published. It's as simple as that. Don't make me wait too long because from the tone of your comment I detect you not only have done this stuff, you have scientific evidence from your own experience that can only prove me wrong. Let us see. I can't wait just like the rest of this blog.

      Btw: Don't make us wait too long because it will mean what it can only mean one thing. Let Larry be the judge. Ok. let us see your scientific work that is as simple as that. Larry, I'm sure of that 100% can verity it without bias. So, don't make us wait very long!!!

    5. Don't make me wait too long because from the tone of your comment I detect you not only have done this stuff,

      In chemistry? No, I don't conduct chemical experiments. I'm not a chemist, so in matters like those discussed above I rely on the opinion of experts and the published results of their experiments. And because I respect thei work, I don't stupidly insist that they must be wrong because I don't like the results.

      you have scientific evidence from your own experience that can only prove me wrong.

      Problem is, you have stated nothing that could be proven wrong. Make a falsifiable claim first, and we can talk.

      As for my own work, it's publicly available. I'm not hiding behind Internet anonymity, unlike you, you little frigging troll.

    6. Let me give you a little lesson on how to debate without resorting to childish inferences and extremist viewpoints.

      1. Regardless of how "safe" Roundup is claimed to be I think we can agree that a diet without Roundup would be preferable to a diet with roundup. If you disagree with this statement, I challenge you to spray a tiny bit of roundup on your meals 3 times a day.

      2. Any time we introduce a chemical which has the ability to drastically alter the ecology of a region, we should be concerned. Unfortunately modern farming practices as well as many other factors have already achieved this by their very nature, but it would be hard to argue against minimizing their effect on the surrounding environment.

      3. You clearly didn't read my comment as you would have seen the alternatives listed. This puts into question your entire argument and makes you seem like an irrational extremist.

      4. Now you're just making inferences which is actually quite embarrassing for a debater of your status. There's nothing healthier than a whole food diet. Supplement, vitamins, and other processed foods should be taken with care or avoided all together if your diet allows it. The same holds true for Roundup.

      5. News flash, scientists can get things wrong occasionally. The fact that you're even debating this weakens your position and makes you seem like an irrational extremist. Using the example of antibiotics is just childish. If there existed a viable alternative to antibiotics in some cases, then it could be considered. The fact is, not consuming Roundup Ready foods isn't potentially fatal and there exist many ready available alternatives, making the comparison between GMO foods and antibiotics illogical at best.

      6. If you honestly believe there's no bias in real world science, in particular when it involves multi-million dollar industries, you're truly lost.

      7. What can I say. You "laugh" at me when I say that skepticism and caution are the best principles to follow? Now you've resorted to undermining your entire blog just to attempt to win a debate. This sort of extremism is near impossible to debate with.

      8. Once again, you have resorted to silly personal inferences which are untrue. It's childish points like these that weaken your argument and cause you to lose respect in other's eyes.

    7. Dear unknown,

      Thank-you for replying. You've done a fine job of representing your opinion and the opinion of others like you.

    8. Piotr Gąsiorowski,

      "Fortunately, science makes claims which can be falsified".

      Too bad this doesn't apply to bacterial

    9. Unknown

      Clearly you don't understand what Roundup RESISTANCE works.

      If a plant is Roundup RESISTANT then when they spray Roundup on the crops to kill the weeds, they need to use LESS Roundup on the crop. Meaning, the likelihood of you getting Roundup in your Food is LESS than if Roundup was used on non-resistant crops.

      Roundup RESISTANT = LESS Roundup used.

      Try to follow along, will you.

    10. @Gordo,

      Roundup kills everything. You don't use it on normal crops because it kills the crops. If you have Roundup reststant crops you'll be using a lot more Roundup than if you didn't. That's why the company that sells Roundup is the same one that developed Roundup-Ready crops.

    11. quite a lot of childish remarks here....shame really.

  3. There was a paper in PNAS recently on reproducing useful natural variants by genetic engineering (the latest in TALEN and CRISPR techniques.)
    Efficient nonmeiotic allele introgression in livestock using custom endonucleases

    It's potentially a lot more efficient to move useful naturally occurring alleles to new strains/species using molecular techniques than to do a lot of time-consuming cross breeding, especially in species with long life spans. This makes clear the essential point that it is ridiculous to talk about "GMOs" being bad, when GMO just means that modern molecular techniques were used to make it. Whether the product is safe/humane or not depends entirely on what genes have been introduced or knocked out and what their characteristics are, not what strain construction methods were used.

  4. Glyphosphate poisoning (not too big a deal for humans)

    However, glyphospate is a major pollutant in rivers and lakes. It's not just about humans. Also, Roundup is more toxic than its active ingredient. As precautionary measure, pregnant or expecting mothers should not be exposed to Roundup.

    1. Glyphosate had been in widespread use for over thirty years. Tons and tons of it are sprayed on crops every year. Its half-life in soil is about three weeks and the half-life in water is about six weeks.

      Can you tell me which rivers and lakes are polluted in a major way?

      Are there any papers in the scientific literature showing that pregnant women or their babies are at risk when exposed to Roundup?

    2. Glyphosate does not equal Roundup.

      You must have missed where I said Roundup is more toxic (i.e., surfactants, solvents, dilutants) than the active ingredient Glyphosate. Inert ingredients is well-known area of research in eco-tox. The US EPA has guidelines for accessing such toxicity and risks associated with chemicals in pesticides/herbicides that are not the principal active agent. Oftentimes the chemicals in these "factory mixes" are not reported, which makes modeling affects challenging. That's why you have to be cautious about making blanket statements and oversimplifying the issue.

      "Two aquatic toxicity studies (Folmar et al. 1979, Wan et al. 1989) have been conducted on glyphosate, POEA, and Roundup which permit a quantitative assessment of the relative toxicities of glyphosate and POEA as well as the effects of combined exposures to these agents. Both of these studies indicate that POEA is substantially more toxic than glyphosate."

      Look at Table 4-1 for LC50 values across fish species. I would expect these values to be significantly lower for Amphibians. And here's a toxicity study of glyphosate-based pesticides on four North American frog species.

      This paper also makes a case for why relying on only LC50 values in your modeling, the current EPA method, does not capture the full life history effects of toxicity as it pertains to developmental time points.

      I base my precautionary measure concerning pregnant mothers on association studies, such as the one below and work done in human cell lines.

      "Birth defects, season of conception, and sex of children born to pesticide applicators living in the Red River Valley of Minnesota, USA."

      Published research measuring Glyphosate contamination in the environment. Takehome is that contamination is low compared to other herbicides but still persistent.
      "Glyphosate was measured at the highest concentration (328 μg/l) in a sample from Riley Spring Pond in Rock Creek National Park. This concentration exceeded the freshwater aquatic life standard for glyphosate of 65 μg/l."

      "Dissipation of glyphosate and aminomethylphosphonic acid in North American forests."

      Title: "Levels of the Herbicide Glyphosate in well water."

      Title: "Herbicide Use in the Management of Roadside Vegetation, Western Oregon 1999-200: Effects on the Water Quality of Nearby Streams"

      Title "Herbicide Treatment of Urban Areas--A Possible Source of Water Contamination."

      Title "Reconnaissance Data for Glyphospate, other Selected Herbicides, their Degradation Products, and Antibiotics in 51 Streams in Nine Midwestern States."

      Title "Glyphosate, Other Herbicides, and Transformation Products in Midwestern Streams."

      Title "Leaching of Glyphosate and Amino-Methylphosphonic Acid from Danish Agricultural Field Sites."

      Title "Pharmaceuticals, Hormones, and Other Organic Wastewater Contaminants in U.S. Streams"

      Title "Impact of Glyphosate-tolerant Soybeans and Glufosinate-tolerant Corn Production on Herbicide Losses in Surface Runoff."

    3. You must have missed where I said Roundup is more toxic (i.e., surfactants, solvents, dilutants) than the active ingredient Glyphosate.

      Sorry. I didn't mean to ignore that point. I'm not familiar with the literature on the additives in Roundup. What I do know is that the GM opponents don't usually say in their literature that glyphosate is safe but some of the other things might be dangerous.

  5. Moderation is key. I am dumbfounded by how many people focus on diet over exercise and moderation. If we eat arguably "sub-optimal" foods, we could more than make up for that differential with the benefits of exercising and living a fit and active life. I have seen way too many "vegans" and "health conscious" individuals... that are so careful to never touch GM foods and whatnot... be fat, and physically unable to do many things... I've seen way too many people that do not care much about this... but are reasonably moderate and live fit active lives... be by FAR better off... You cannot hibernate in your cave and not exercise and think you can follow the american, BIG is KING diet... as long as you eat the BEST most organic FOOD. This is just a self-defense mechanism at best in psychology terms... The reality of the matter... is you need to be reasonable and not fanatic... you need to also balance the benefits of exercise and rather than look for an excuse to eat as much as you can of the PERFECT food -- just eat less, exercise more, and enjoy life. Too many people missing the bloody point.

  6. Humans, cows, chickens, pigs, fish, strawberries, etc are all genetically modified organisms. Their genetic makeup has been modified through thousands of years of evolution. Though they are the same species of animal, one person's Labrador looks different from another person's Chihuahua through hundreds of years of breeding, which is also selectively modifying genetics. The only difference with genetically modified food is that scientists are prompting similar changes in a lab rather than hundreds or thousands of years of selective breeding. Genetically modified foods are no less safe than wild foods which can also be unhealthy (poison berries / foods that cause allergic reactions) if you don't safely test them prior to human consumption.