Farmarians online community, Post Of The Day | #1. Scientific reasons simple GMO labeling might mislead about health risks

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The following is a post-response pair.


New England Journal of Medicine, published last month.

Summary: GMOs are leading to increased use of pesticides; more safety studies should be conducted; and GMO-containing food products should be labeled as such.


“But widespread adoption of herbicide-resistant crops has led to overreliance on herbicides and, in particular, on glyphosate.5 In the United States, glyphosate use has increased by a factor of more than 250 — from 0.4 million kg in 1974 to 113 million kg in 2014. Global use has increased by a factor of more than 10. Not surprisingly, glyphosate-resistant weeds have emerged and are found today on nearly 100 million acres in 36 states. Fields must now be treated with multiple herbicides, including 2,4-D, a component of the Agent Orange defoliant used in the Vietnam War.

“The first of the two developments that raise fresh concerns about the safety of GM crops is a 2014 decision by the Environmental Protection Agency (EPA) to approve Enlist Duo, a new combination herbicide comprising glyphosate plus 2,4-D. Enlist Duo was formulated to combat herbicide resistance. It will be marketed in tandem with newly approved seeds genetically engineered to resist glyphosate, 2,4-D, and multiple other herbicides. The EPA anticipates that a 3-to-7-fold increase in 2,4-D use will result.

“We believe the time has come to revisit the United States’ reluctance to label GM foods. Labeling will deliver multiple benefits. It is essential for tracking emergence of novel food allergies and assessing effects of chemical herbicides applied to GM crops. It would respect the wishes of a growing number of consumers who insist they have a right to know what foods they are buying and how they were produced. And the argument that there is nothing new about genetic rearrangement misses the point that GM crops are now the agricultural products most heavily treated with herbicides and that two of these herbicides may pose risks of cancer. We hope, in light of this new information, that the FDA will reconsider labeling of GM foods and couple it with adequately funded, long-term postmarketing surveillance.”


by Chad Niederhuth

Several things. First…I highly recommend Andrew Kniss’s take on this…who by training, is more of an expert on herbicide usage than Benbrook

1) This is an opinion piece. Scientific and Medical journals regularly publish opinion pieces…they should not be treated in the same way as peer-reviewed research, as the the editorial and review process is quite different.

2) Charles Benbrook does not show that they increase pesticide usage. He shows that they have led to an increase in glyphosate…but this is not the same as saying they increase pesticide usage (which includes insecticides, fungicides, and herbicides)….its not even the same as saying that it has increased herbicide usage, as in most cases glyphosate has simply replaced older and more toxic herbicides…as in the case of corn production:

Rather, GMOs have significantly reduced pesticide use by reducing insecticide use first and foremost.

3) Benbrook cites some astounding number…glyphosate use has increased by a factor of 250…scary…until you realize that rapid adoption of new technology will always increase rapidly…even if as a whole, the situation is very different. Glyphosate use has replaced other herbicides. So while glyphosate use went up 250 fold. Alachor…a once common corn herbicide has decreased ~60 fold. Cyanazine has decreased ~45 fold…so on and so on for many herbicides.

To put things in persepective, Alachor has an LD50 of 930 mg/kg while glyphosate has an LD50 of 5600 mg/kg…making glyphosate over 5 times less toxic than Alachor.

4) It should be noted that not all the increase in glyphosate use is due to GMOs. 18% of all glyphosate is used on non-GMOs. For that matter, we should also keep in mind that herbicide tolerance can be achieved in many ways…GMOs being only one way. When Chipotle switched to non-GMO sunflower oil, citing the negative effects of glyphosate and soybean oil…what they conveniently left out was the fact that many sunflowers are herbicide resistant and that this was developed by traditional breeding. They also conveniently didn’t mention that the herbicide resistance in traditionally bred sunflowers it to ALS inhibitors. These herbicides have far more resistant weeds than glyphosate and they are ~ twice as toxic as glyphosate.

This of course illustrates, that the traits Benbrook is concerned with are not limited to GMOs and why focusing on the method of production is fallacious. We should focus on the specific trait, not how it was made.

5) Benbrook makes misleading claims, such as the idea that the risk assessments for Enlist Dou lacked ecological assessments…that couldn’t be further from the truth. This is the EPA’s environmental risk assessment…be warned, its 103 pages long….

6) Benbrook raise the issue of Glyphosate and 2,4-D being classified as probable and possible carcinogens respectively. Sounds scary, but as rational beings, we should ask what this means. For one, the only group to list it as such was the IARC…there are numerous groups, government agencies that do so. The US, German, etc agencies that do so typically take 5 years of review to classify a substance. The IARC did so in a matter of weeks. It also does not conduct original research…it simply reviews it.

The American Cancer society does a much better job explaining the classification system and the actual reality of risk:

“Carcinogens do not cause cancer in every case, all the time. Substances labeled as carcinogens may have different levels of cancer-causing potential. Some may cause cancer only after prolonged, high levels of exposure. And for any particular person, the risk of developing cancer depends on many factors, including how they are exposed to a carcinogen, the length and intensity of the exposure, and the person’s genetic makeup.”


“The lists themselves say nothing about how likely it is that an agent will cause cancer. Carcinogens do not cause cancer at all times, under all circumstances. Some may only be carcinogenic if a person is exposed in a certain way (for example, swallowing it as opposed to touching it). Some may only cause cancer in people who have a certain genetic makeup. Some of these agents may lead to cancer after only a very small exposure, while others might require intense exposure over many years. Again, you should refer to the agencies’ reports for specifics.

Even if a substance or exposure is known or suspected to cause cancer, this does not necessarily mean that it can or should be avoided at all costs. For example, estrogen is a known carcinogen that occurs naturally in the body. Also, exposure to ionizing radiation is known to cause cancer, with increased risks even at low levels of exposure. Yet there is no way to completely prevent exposure to natural sources of radiation such as cosmic radiation from the sun or radon in soil. These lists also include many commonly used medicines, particularly some hormones and drugs used to treat cancer. For example, tamoxifen increases the risk of certain kinds of uterine cancer but can be very useful in treating some breast cancers, which may be more important for some women. If you have questions about a medicine that appears on one of these lists, be sure to ask your doctor.”

As the ACS points out…estrogen is a KNOWN carcinogen…whereas glyphosate is only listed as a probable one. Alcohol is a known human carcinogen. Caffeine is a probable one just like glyphosate.

The real question then that we should be asking is what the data is that supports this listing and under what conditions is it valid. To simply list it as a carcinogen in the context of increased glyphosate use as Benbrook has done is in my opinion a form of fear-mongering. It is meant to scare, but it doesn’t really provide you with the background information necessary to make an informed decision.

7) Based on this focus on a single trait…Landrigan and Benbrook call for labeling of GMOs…however, that is not informative. As previously pointed out, there are herbicide tolerant non-GMOs that are sprayed with worst herbicides…these would not be labeled. In fact these could be labeled as “non-GMO” and so likely assumed safe by consumers who don’t know better. Furthermore, such a label does not tell you if it is a herbicide tolerant GMO, a Bt GMO, a nutrient enriched GMO (high-oleic soybean oil for instance) or say a virus resistant GMO. Its an uninformative label.

Comments: It would seem to me that what we need is not just GMO labels, but really, a label that contains the most relevant information related to the potential toxicity of the production process. GMO labels in this respect may mislead. On the other hand, people might hold philosophical reservations about GMOs–reservations that are not directly related to safety; these people would still benefit from GMO labels. Nonetheless, the points raised are very interesting; if accurate, they show how far off, in many respects, the debate about GMO labeling is. It’s not only about consumer choice–but, rather, if consumers really want to be informed (rather than simply think they are), they need much more than binary labeling disclosing the mere presence or absence of GMOs.

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