The Public Health Ramifications of GMOs and Herbicides

Toxic Glyphosate

Story at-a-glance

  • Next-generation GMOs are designed to be resistant to combinations of herbicides. Enlist Duo, which was recently green lighted, is resistant to both glyphosate and 2,4-D, a major ingredient in Agent Orange
  • Research shows glyphosate in combination with aluminum synergistically induce pineal gland pathology, which in turn is linked to gut dysbiosis and neurological disease
  • Several hundred pages’ worth of research is included, detailing the hazards associated with glyphosate on human, animal, and environmental health


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

On August 20, 2015, Philip J. Landrigan, M.D., and Charles Benbrook, Ph.D. published a paper1,2 in the one of the most prestigious medical journals, the New England Journal of Medicine (NEJM) on the topic of genetically modified organisms (GMOs), herbicides, and public health, noting that:

“... [T]he application of biotechnology to agriculture has been rapid and aggressive. The vast majority of the corn and soybeans grown in the United States are now genetically engineered.

Foods produced from GM crops have become ubiquitous...Two recent developments are dramatically changing the GMO landscape.

First, there have been sharp increases in the amounts and numbers of chemical herbicides applied to GM crops, and still further increases — the largest in a generation — are scheduled to occur in the next few years.

Second, the International Agency for Research on Cancer (IARC) has classified glyphosate, the herbicide most widely used on GM crops, as a ‘probable human carcinogen’ and classified a second herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), as a ‘possible human carcinogen.’”

The ‘Answer’ to Herbicide Resistance Is Bound to Make Food Increasingly Toxic

The authors recount how genetically engineered (GE) herbicide-resistant crops have led to a dramatic increase in herbicide application due to mounting resistance among weeds.

They then go on to argue that the science and risk assessment of the next-generation of GE crops — touted as the “answer” to growing resistance — is seriously flawed.

These next-gen crops are designed to be resistant to combinations of herbicides. Enlist Duo, which was recently green lighted, is resistant to both glyphosate and 2,4-D; the latter of which was a major ingredient in Agent Orange, used with devastating effect during the Vietnam War.

As a result of this approval, the US Environmental Protection Agency (EPA) expects use of 2,4-D to increase anywhere from three to seven times in coming years.

Benbrook and Landrigan note that the science supporting Enlist Duo consists solely of unpublished toxicology studies done by the herbicide manufacturer in the 1980s and ‘90s.

These studies predate more recent scientific discoveries of how chemicals create adverse health effects even at very low doses, including endocrine and epigenetic effects.

They also criticize the risk assessment of Enlist Duo, saying it “gave little consideration to potential health effects in infants and children, thus contravening federal pesticide law.”

The risk assessment also did not adequately account for ecological impact on pollinators, including the monarch butterfly, which is being decimated by massive glyphosate applications on vast fields of GE crops.

Last but not least, the assessment only considered glyphosate in isolation, despite studies showing that glyphosate in combination with surfactants and other chemicals tend to synergistically increase their toxic potential.

Evidence Against Glyphosate Keeps Mounting

Research3 published in 2007 found that aerial spraying of glyphosate in combination with a surfactant solution resulted in DNA damage in those exposed.  

Another study4 published this year found that glyphosate in combination with aluminum synergistically induced pineal gland pathology, which in turn was linked to gut dysbiosis and neurological disease.

The study abstract offers a condensed layman’s summary of the many mechanisms of harm and their synergistic effects, which can be difficult to understand without some explanation:

“Many neurological diseases, including autism, depression, dementia, anxiety disorder, and Parkinson’s disease, are associated with abnormal sleep patterns, which are directly linked to pineal gland dysfunction.

The pineal gland is highly susceptible to environmental toxicants. Two pervasive substances in modern industrialized nations are aluminum and glyphosate, the active ingredient in the herbicide, Roundup ®. In this paper, we show how these two toxicants work synergistically to induce neurological damage.

Glyphosate disrupts gut bacteria, leading to an overgrowth of Clostridium difficile. Its toxic product, p-cresol, is linked to autism in both human and mouse models. p-Cresol enhances uptake of aluminum via transferrin.

Anemia, a result of both aluminum disruption of heme and impaired heme synthesis by glyphosate, leads to hypoxia, which induces increased pineal gland transferrin synthesis.

Premature birth is associated with hypoxic stress and with substantial increased risk to the subsequent development of autism, linking hypoxia to autism.

Glyphosate chelates aluminum, allowing ingested aluminum to bypass the gut barrier. This leads to anemia-induced hypoxia, promoting neurotoxicity and damaging the pineal gland.

Both glyphosate and aluminum disrupt cytochrome P450 enzymes, which are involved in melatonin metabolism. Furthermore, melatonin is derived from tryptophan, whose synthesis in plants and microbes is blocked by glyphosate.

We also demonstrate a plausible role for vitamin D3 dysbiosis in impaired gut function and impaired serotonin synthesis. This paper proposes that impaired sulfate supply to the brain mediates the damage induced by the synergistic action of aluminum and glyphosate on the pineal gland and related midbrain nuclei.”

A Bonanza of Research Material for the Studious

For a more thorough review of the published studies5 questioning the safety of glyphosate in terms of its effects on human and animal health, please see this compilation by Dr. Alex Vasquez. It contains 220 pages’ worth of research — more than enough to satisfy most critical thinkers.

Another illuminating and heavily referenced 80-page report6 you can read through at your leisure is “Banishing Glyphosate,” authored by Drs. Eva Sirinathsinghji and Mae-Wan Ho, with cooperation from six other researchers, including Dr. Don Huber and Dr. Nancy Swanson.

Dr. Huber has also written a 42-page report7 titled “Ag Chemicals and Crop Nutrient Interactions.” In it he explains how extensive use of glyphosate and the adoption of glyphosate-tolerant GE crops have resulted in essential micro- and macronutrient deficiencies in plants, and the increased need for micronutrient remediation in the soil.

A study8 published earlier this year shows that glyphosate-based herbicides adversely affect the activity and reproduction of earthworms, which are important players in healthy soils. Herbicide application also increased nitrate concentrations in the soil by 1,592 percent, and phosphate concentrations by 127 percent, thereby adding to the risk of nutrient leaching into and polluting nearby water sources and groundwater aquifers. Research9 from 2003 also found that growing Bt corn had an adverse effect on the microbial activity in the soil by significantly increasing the saturated to unsaturated lipid ratios in the soil.

It’s Time to Take a Precautionary Approach to Biotechnology

Landrigan and Benbrook offer two recommendations in their paper. First, they suggest the EPA delay permission to use Enlist Duo, as this decision was not only based on outdated never-published research and an incomplete risk assessment, these studies also predate the IARC’s reclassifications of both glyphosate and 2,4-D as probable and possible carcinogens respectively. Secondly, they urge revisiting “the United States' reluctance to label GM foods,” noting that labeling is essential for:

  • Tracking emergence of novel food allergies
  • Assessing effects of herbicides applied to GE crops
  • Respecting the wishes of consumers who want to know how their food was produced

Considering the fact that a) glyphosate has been shown to accumulate in GE crops,10 b) chronically ill people have been found to have significantly higher levels of glyphosate in their urine than healthy populations,11 and c) the US government does not test food for glyphosate, labeling GE foods is also one of the only ways to alert consumers of the potential presence of elevated levels of toxic herbicides in their food. Besides increased glyphosate accumulation, GE crops have also been shown to have a less healthy nutritional profile compared to non-GE varieties.12

In conclusion, Landrigan and Benbrook write:

“... GM foods and the herbicides applied to them may pose hazards to human health that were not examined in previous assessments. We believe that the time has therefore come to thoroughly reconsider all aspects of the safety of plant biotechnology...

[T]he 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.”

Industry Blowback Was Swift, and Expected...

Dr. Benbrook is well-known for his critical stance against GMOs, so it came as no surprise that his name on this article led to instantaneous blowback from the industry. The paper was barely out of embargo before Science 2.0 published a made-to-order character assassination piece13 penned by Hank Campbell, saying:

Dr. Chuck Benbrook is an adjunct at Washington State University but he calls himself a research professor. Why so many organic food proponents believe a guy about something as complex as genetic modification when he can't even get his own title correct is a mystery we can't solve today but his credibility sure won't be bolstered up by an op-ed he just published in the New England Journal of Medicine.”

Hank Campbell is the founder of Science 2.0, and the newly elected president of the American Council on Science and Health (ACSH), the stated purpose of which is to “provide an evidence-based counterpoint to the wave of anti-science claims.” 

I predict Campbell’s vitriolic attack was just the first salvo in what may turn into a more coordinated effort to get Benbrook and Landrigan’s article retracted and removed from the New England Journal of Medicine. The same strategy they used to discredit Dr. Seralini’s GMO rat study. Jon Entine and the Genetic Literacy Project (GLP)  recently started the Genetic Expert News Service14 to further slant the conversation on GMOs.

All of these scientific looking sites link back to each other’s articles and engage in coordinated sharing through skeptic networks, weaving one big dirty web of misdirection and obfuscation. For example, Campbell criticizes Benbrook’s article as being short on scientific evidence. Meanwhile, his own article offers no scientific support to rebut any of Landrigan and Benbrook’s claims. It reads more like a blog note of a sullen teenager than a professional tasked with upholding scientific integrity.

Food Industry Is Spending Tens of Millions Lobbying for Less Transparency

A question worth asking is why is the food industry pouring tens of millions of dollars into lobbying against transparency? Could it be because they have something to hide? According to Civil Eats,15 food and beverage companies have spent $51.6 million on a series of efforts to defeat GMO labeling laws alone, including lobbing for HR 1599, which would bar states from implementing their own GMO labeling laws.

An analysis16 by the Environmental Working Group (EWG) shows nearly a quarter of these funds came from Coca-Cola, General Mills, Kellogg’s, Land O’Lakes, and PepsiCo. But we’re not only faced with Rep. Mike Pompeo’s bill HR 1599, “The Safe and Accurate Food Labeling Act,” more commonly referred to as the "Deny Americans the Right to Know" or DARK Act, which was recently passed by the US House of Representatives. Other bills seek to:

  • Remove country-of-origin labeling (COOL) requirements for beef, chicken, and pork (HR 239317). Supporters of this bill have spent $54.2 million on lobbying efforts.
  • Eliminate the need for permits to discharge pesticides into rivers, lakes, streams, and other bodies of water regulated under the Clean Water Act (S150018). As noted by Civil Eats: “Because the bill was just introduced in June, a good accounting of lobbying on its behalf is not yet available... But when virtually the same bill was introduced in 2013... agribusinesses and agricultural organizations and trade associations...  spent more than $11 million lobbying for the bill during 2013 and 2014.”
  • Coincidentally (or not), a recent study by the US Geological Survey found neonicotinoid insecticides in over half of all streams sampled in both urban and agricultural areas in 24 states and Puerto Rico.19,20

    Neonicotinoids are used primarily on corn and soybeans, both as aerial spray and as prophylactic seed treatment. So now, as widespread pollution of waterways with these agricultural toxins is becoming more apparent, related industries are pouring millions into laws that will make it easier for them to hide all this damage rather than rally around sustainable, non-toxic, and regenerative solutions.

International trade agreements also threaten to restrict transparency about food — how it’s produced, and where it comes from. In addition to hampering GMO labeling efforts in the US, provisions in both the Trans-Pacific Partnership (TPP) and the Transatlantic Trade and Investment Partnership (TTIP) would also effectively force participating nations to eliminate country of origin from their food labels or run the risk of being sued for harming trade.

Glyphosate Promotes Human and Animal Disease

In a recently published study21 titled “The High Cost of Pesticides: Human and Animal Diseases,” Judy Hoy, an expert on Montana wildlife, along with Dr. Nancy Swanson and Dr. Stephanie Seneff poured through data from the Centers for Disease Control and Prevention’s (CDC) database, looking for correspondences between animal and human disease, and correlations with pesticide usage.

Several of the plotted charts show animal and human diseases rising in step with glyphosate usage on corn and soy crops.

This includes conditions such as failure to thrive, congenital heart defects, enlarged right ventricle, liver cancer, and in newborns: lung problems, metabolic disorders, and genitourinary disorders. Overwhelmingly, the evidence points to the fact that our food supply is rapidly deteriorating in quality. Excessive pesticide and herbicide use is also decimating soil- and water quality.

The writing is on the wall, and the situation is grim indeed — and made even grimmer by the fact that the food and chemical technology industries are fighting tooth and nail to hide what’s happening, and worse, prevent even the most astute people from making informed choices. But that doesn’t mean we acquiesce to the seemingly inevitable and simply “roll over and die.” No! Now is not the time become paralyzed in the face of immense obstacles. Now is the time to stand up and fight for what you believe is right; fight for the world you want for your children.


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