Fact Check

The Real Reason Wheat is Toxic

Are U.S. farmers saturating wheat crops with Monsanto's Roundup herbicide as a desiccant to facilitate a quicker harvest?

Published Dec. 25, 2014

Updated July 26, 2017
 (S-F / Shutterstock.com)
Image courtesy of S-F / Shutterstock.com
U.S. farmers are saturating wheat crops with the herbicide Roundup as a desiccant before each harvest, causing an increase in wheat-related ailments.
What's True

RoundUp (glyphosate) is sometimes used as a desiccant to alter the timing of wheat harvests, but that practice is far from common in the United States.

What's False

Claims that the practice is both widespread and the cause of digestive ailments are unsupported by credible evidence or accurately reported data.

On 13 November 2014, the web site "Healthy Home Economist" published an article by Sarah Pope, which reported that the reason people sometimes (but not always) experience digestive ailments after consuming wheat in the U.S. is that American farmers disproportionately practice spraying wheat the herbicide glyphosate (RoundUp) to modify the time of a wheat harvest:

The stories became far too frequent to ignore. Emails from folks with allergic or digestive issues to wheat in the United States experienced no symptoms whatsoever when they tried eating pasta on vacation in Italy. Confused parents wondering why wheat consumption sometimes triggered autoimmune reactions in their children but not at other times.The bad news is that the problem lies with the manner in which wheat is harvested by conventional wheat farmers.

Standard, recommended wheat harvest protocol in the United States is to drench the wheat fields with Roundup several days before the combine harvesters work through the fields as withered, dead wheat plants are less taxing on the farm equipment and allow for an earlier and easier harvest.

Using Roundup as a desiccant on the wheat fields prior to harvest may save the farmer money and increase profits, but it is devastating to the health of the consumer who ultimately consumes those ground up wheat kernels which have absorbed a significant amount of Roundup!

The Italian Pasta Example Doesn’t Hold Much Water

Before digging into the practice of crop desiccation, it is important to realize that the entirely anecdotal example of people sensitive to gluten deriving sickness from American pasta and not from Italian pasta (a thinly disguised version of the appeal to nature fallacy) requires wheat in Italy, as a blanket rule, to contain no wheat processed in a country where glyphosate is used in its production.

Such an assertion, however, would be false — making the claim that glyphosate is the cause for different reactions to pasta in the two countries a hard one to make with logical consistency. Italy actually imports up to 40 percent of the wheat used in their pasta-making from other countries, including including those that make use of glyphosate.

How Widespread is the Use of Glyphosate as a Desiccant?

Glyphosate is the most commonly used herbicide in the world and an integral part of the global agricultural system, due dominantly to the widespread adoption of genetically modified glyphosate resistant crops. In its traditional use as a broad spectrum herbicide, it is either sprayed before planting crops to clear a field, or as a maintenance tool after planting if applied to glyphosate-resistant crops. These uses, however, differ from the practice of crop desiccation, which aims to increase the rate at which a plant loses moisture to change the timing of a harvest. The concern with this kind of use, which would occur 7 to 10 days before harvest, is that it would leave increased amounts of glyphosate residue on final product because its application is closer to harvest time.

Glyphosate is, indeed, sometimes used for this purpose — the necessity of which is dictated by what crop is being grown and the environmental conditions in which it is being grown — but it is not typically the first choice for the job, as there are other chemicals specifically designed for that use, as discussed by the Alberta Department of Agriculture and Forestry, a region that practices crop desiccation on wheat:

True desiccants [such as RegloneTM]  are harvest management tools that rapidly kill above ground growth of crops and weeds, allowing for rapid dry down and an earlier harvest. Desiccants will not give long-term weed control and any late moisture may cause both the weeds and the crop to start to re-grow.

Pre-harvest glyphosate application is generally used for perennial weed control. It can be used as a harvest management tool for dry down but the effects take much longer to appear.

In her post, Pope asserts:

According to the US Department of Agriculture, 99% of durum wheat, 97% of spring wheat, and 61% of winter wheat [in the U.S.] has been doused with Roundup as part of the harvesting process.

This statement is misleading, as it conflates the use of glyphosate in general with the use of glyphosate as a desiccant. The statistic Pope cites, sourced from USDA survey data, actually works against her argument that wheat produced specifically by the United States would be disproportionately affected by pre-harvest glyphosate desiccation, as it shows that the most common wheat produced in the United States (winter wheat accounts for 70 to 80 percent of U.S. wheat production) is the one with the least reliance on glyphosate.

While the data on glyphosate use in pre-harvest application is either proprietary or non-existent, the testimony of numerous farmers speak to the fact that glyphosate desiccation is a rare practice in the United States, with its use generally relegated to North and South Dakota. One such piece, republished on Huffington Post, reports:

Pre-harvesting wheat with glyphosate (most commonly Roundup) is not something the majority of wheat farmers across the nation do. There is a small sector and region of wheat production that practices this: mainly North Dakota, small parts of South Dakota, and parts of Canada. In the United States, North Dakota represents about 5% of total wheat acres produced. We are, however, the second hard red spring wheat producer in the nation. So the claim that this occurs everywhere is not at all valid or true since only about 5% of the total production practices this pre-harvesting.

We ourselves surveyed a number of farmers in the Walla Walla Valley, which has been a large wheat-growing area for many years, and found none who had engaged in — or even heard of — the practice of "desiccating" wheat with Roundup just prior to harvest.

While the practice of glyphosate desiccation exists in some regions in the United States, the claim that it is a “common” practice in America is not supported by any correctly described data.

The “Research” Behind The Claim

The stated evidence for the hypothesis that glyphosate in American wheat is contributing to rising gluten sensitivities is based on two questionable sources of data. The first is the anecdotal claim about those with allergic or digestive issues to wheat in the United States "experiencing no symptoms whatsoever when they try eating pasta on vacation in Italy". Outside of the factual problems discussed at the top of this piece,  such examples are problematic as evidence because they’re non-random, self-selected samples and not scientifically controlled and collected data.

The second piece of evidence is research attributed to Massachusetts Institute of Technology researcher Stephanie Seneff:

According to Dr. Stephanie Seneff of MIT who has studied the issue in depth and who I recently saw present on the subject at a nutritional Conference in Indianapolis, desiccating non-organic wheat crops with glyphosate just before harvest came into vogue late in the 1990’s with the result that most of the non-organic wheat in the United States is now contaminated with it.

Senef is a controversial senior research scientist at the Computer Science and Artificial Intelligence Laboratory at MIT who, despite a lack of background in any relevant topics, has made a name for herself by connecting both vaccines and glyphosate to diseases ranging from celiac’s disease to Alzheimer's and autism. The cited paper, a 2013 study in the journal Entropy, makes the following claim:

Glyphosate enhances the damaging effects of other food borne chemical residues and environmental toxins. Negative impact on the body is insidious and manifests slowly over time as inflammation damages cellular systems throughout the body. [...]

Consequences are most of the diseases and conditions associated with a Western diet, which include gastrointestinal disorders, obesity, diabetes, heart disease, depression, autism, infertility, cancer and Alzheimer’s disease.

To say this paper lies outside the scientific mainstream would be an understatement. It is speculative and provides no data of its own, cites discredited or even officially retracted work, and even has had an editorial statement of concern affixed to it:

The editors would like to issue an Expression of Concern to make readers aware that the approach to collating literature citations for this article was likely not systematic and may not reflect the spectrum of opinions on the issues covered by the article.

Even if the paper was valid in its wildly broad and aggressively speculative hypothesis that glyphosate and vaccines combine to create most of the Western world’s health problems, using it as a source for claims of widespread pre-harvest glyphosate desiccation of wheat in the United States is just as problematic, as it does not provide any accurately reported research in defense of that claim.

While the health effects of glyphosate on humans is a controversial topic to which different governmental health agencies have reached different conclusions (though most conclude it is not a risk to human health), the notion that differences in the production of wheat between America and the rest of the world are the causes of differing gastrointestinal reactions to similar food items in different locations lacks both supporting evidence and internal consistency. Claims of the widespread practice glyphosate desiccation of wheat in the United States are similarly without merit.

Our rating of "mixture" recognizes that, indeed, glyphosate is sometimes used as a desiccant, but that its practice is far from common in the United States. We reject the notion, however, that this "common" practice of U.S. farmers "saturating" wheat crops with Roundup herbicide as a desiccant before each harvest has been causing an increase in wheat-related ailments, as these claims are unsupported even by the research cited in articles making such a claim.


Pope, Sarah.   "The Real Reason Wheat is Toxic (it’s not the gluten)"     The Healthy Home Economist.   20 February 2017.

Williams, Megan.   "Italy's Farmers 'Demonizing' Canadian Wheat in Bid to Protect Domestic Industry."     CBC News.   6 July 2017.

Czap, Nick.   "Pastas With a New Selling Point: They’re All Italian."     New York Times.   3 January 2017.

Benbrook, Charles, M.   "Trends in Glyphosate Herbicide Use in the United States and Globally."     New York Times.   2 February 2016.

U.S. Department of Agriculture.   "2012 Agricultural Chemical Use Survey, Wheat."     May 2013.

U.S. Department of Agriculture.   "Wheat, Background"     Accessed July 25 2017.

Rohrich, Jenny, Dewey.   "The Truth About Toxic Wheat"     Huffington Post.   19 January 2015.

Kloor, Keith.   "When Media Uncritically Cover Pseudoscience."     Discover.   26 April 2013.

Samsel, Anthony, and Seneff, Stephanie.   "Glyphosate’s Suppression of Cytochrome P450 Enzymes and Amino Acid Biosynthesis by the Gut Microbiome: Pathways to Modern Diseases."     Entropy.   18 April 2013.

The BMJ.   "Wakefield’s Article Linking MMR Vaccine and Autism Was Fraudulent.”     6 January 2011.

Stokstad, Erik.   "Why Europe May Ban the Most Popular Weed Killer in the World"     Science.   17 June 2016.

Portier, Christopher, J., et al.   "Differences in the carcinogenic evaluation of glyphosate between the International Agency for Research on Cancer (IARC) and the European Food Safety Authority (EFSA)."     Journal of Epidemiology and Community Health.   3 March 2016.


27 July 2017, 11:22 A.M.: Added more on the scientific discussion of glyphosate and gluten intolerance.

David Mikkelson founded the site now known as snopes.com back in 1994.

Alex Kasprak is an investigative journalist and science writer reporting on scientific misinformation, online fraud, and financial crime.