In April of 2013, Stephanie Seneff and Anthony Samsel published a paper in the online journal, Entropy, titled, “Glyphosate’s Suppression of Cytochrome P450 Enzymes and Amino Acid Biosynthesis by the Gut Microbiome: Pathways to Modern Diseases”. The paper made a big online splash among the anti GMO and anti big agro online community with headlines like, “Is Roundup the Cause of ‘Gluten Intolerance’? A compelling new peer-reviewed report from two U.S. scientists argues that increased use of Monsanto’s glyphosate herbicide (trade name Roundup) could be the cause of the epidemic of symptoms labeled as ‘gluten intolerance.'” I’ll come back to this headline later.
Glyphosate is the active ingredient in the herbicide Roundup. There certainly may be a causative link between glyphosate and toxicity (cell death, metabolic problems, etc.) in humans, and wondering whether there is a causative link between industrial chemicals like glyphosate and human disease and metabolic disorders is an important question. The answer to the question should involve carefully controlled and repeatable experimental studies. But as you will read below, the Samsel and Seneff study that is getting all the recent anti GMO and anti big agro press is nothing of the sort.
(Update 3 April 2015: The New York Times recently reported on a World Health Organization study that glyphosate “probably” causes cancer in humans–“In that paper, the reviewers cited studies from the United States, Canada and Sweden suggesting that people exposed to glyphosate had a higher incidence of non-Hodgkin’s lymphoma, even after correcting for exposure to other chemicals. But a large and long study of pesticide applicators on American farms did not find any problems.”–NYTimes) (Update #2, 30 November 2015: A 12 November 2015 assessment from the European Food Safety Authority found that pure glyphosate is unlikely to increase the risk of cancer.)
(Update 17 September 2016: NPR recently reported on an EPA report that glyphosate likely does not cause cancer.)
First, some details on glyphosate the pesticide (herbicide). A credible source for glyphosate chemistry and biology can be found at the National Pesticide Information Center (NPIC) at Oregon State University.
From the NPIC glyphosate fact sheet, we can glean that if a person was in the habit of eating the current crops that have been genetically modified to resist glyphosate, his or her diet would be focused heavily on soy (although mostly fed to livestock), feed corn (also mostly fed to livestock, but also used to make corn syrup and ethanol), canola, alfalfa, cotton, and sorghum. The reference dose for glyphosate for humans is 1.75 mg/kg/day. According to the NPIC, a reference dose “is an estimate of the quantity of chemical that a person could be exposed to every day for the rest of [his or her] life with no appreciable risk of adverse health effects.” So for a 75 kg person (165 lbs), the reference dose would be around 131 mg per day. A person who drinks a 12 oz cup of coffee can easily consume a mass of caffeine (a psychoactive drug that evolved as an insecticide in plants) equal to 131 mg or more.
At this point, a little perspective on masses and toxicity is in order. Humans both knowingly and unknowingly add more than 600 times the glyphosate reference dose to their diets every day in the form of sugar. Indeed, by 1996, the daily exposure of the average American to added sugar was 80 grams (320 additional calories per day). Constant exposure to sugar in this amount causes obesity and type II diabetes and is clearly deadly in the long term. Ironically, plenty of sugar is sold at Whole Foods, a grocer that prides itself in offering all organic and GMO free products.
But how do we improve our scientific knowledge on the effects of glyphosate on human health beyond an NPIC fact sheet? Is the best scientific route by way of two computer scientists, with interests in bringing down GMOs and big agro, that attempt to write a biochemistry paper? The story of the bogus nature of this paper is not new, but it is worth telling again. It is also worth a critical analysis of two journals claiming to be scientific, but that are publishing papers that are not.
The Samsel and Seneff paper was originally published in the journal Entropy, an interdisciplinary free access online journal with a pay-to-play price tag of $1,352.00. Entropy is published by the Multidisciplinary Digital Publishing Institute (MDPI), which, according to Jeffrey Beall at Scholarly Open Access, is a “potential, possible, or probable predatory scholarly open-access publisher.” The paper itself is 48 pages of other peoples’ work and Samsel and Seneff establish no causative link between glyphosate and human disease. Indeed, the word “associated” is used 43 times in the paper and “association” appears 24 times. Their main hypothesis is something called “exogenous semiotic entropy,” a meaningless concept that exists nowhere in the world but in this paper. The authors present their readers with an explanation—that glyphosate is behind dozens of human health problems—and then drum up all the support they can for it. All without doing any hypothesis testing or experiments themselves. This approach is the opposite of dispassionate and skeptical science.
And who are these “American scientists”? Anthony Samsel is a retired self-employed computer science consultant who has somehow become an expert in glyphosate biochemistry and human disease. Yet, according to The Web Of Science search engine, Samsel has only published two scientific papers in his career. Stephanie Seneff is a 65-yr-old computer scientist in the Department of Artificial Intelligence at the Massachusetts Institute of Technology. Like Samsel, Seneff has magically become an expert in glyphosate biochemistry and human disease while maintaining a career in artificial intelligence. Seneff’s last eight articles have also been published in the journal Entropy, which means she and her coauthors have spent $10,816.00 to publish in the last two years. Recently, Seneff has been publicly linking glyphosate to autism and claims that glyphosate exists in unusually high concentrations in the breast milk of American mothers, a claim that cannot be traced to any peer reviewed scientific literature. Again, it is unbelievable that these two computer scientists, with no experience in medicine, biochemistry, or experimental biology, are being received with any credibility, especially by the anti GMO and anti big agro community.
A strikingly similar (and perhaps self-plagiarized) but sexier version of this paper was published by Samsel and Seneff in an obscure journal called Interdisciplinary Toxicology. In February of 2014, the pseudoscience-promoting online magazine, Mother Earth News, published an article that sensationally summarized the Samsel and Seneff glyphosate paper from Interdisciplinary Toxicology.
Interdisciplinary Toxicology was started in June of 2008 by a Slovakian institute at the Slovak Academy of Sciences called the Institute of Experimental Pharmacology and Toxicology. I used the Web of Science search engine to collect all of the papers published in Interdisciplinary Toxicology from its first issue dated June, 2008, to the issue dated December 2013. I also used the journal’s website to collect all papers published in 2014 (a March and a June issue). The Web of Science provided citation data for the 179 articles published through December 2013, and Google Scholar provided citation data for the 15 papers published in 2014. Eighty (41%) of the 194 articles published in this journal in the last six years have never been cited. The mean citations per paper is 2.8, mostly by 15 papers, which have been cited a combined 270 times. The median number of citations for the journal’s papers is 1 and the mode is 0.
I have no idea if the scholarly society behind Interdisciplinary Toxicology is legit. My assumption is that the journal was created as a place for its members to publish. For example, the Director of the Slovak Institute of Experimental Pharmacology & Toxicology is Michal Dubovický. Dubovický is also Editor-in-Chief of Interdisciplinary Toxicology. Dubovický has 53 career publications according to the Web of Science. Since June of 2008, when Interdisciplinary Toxicology was launched, he has published 27 times. Two of those publications were editorials in Interdisciplinary Toxicology and 10 were full length papers in the journal. So, 40% of Dubovický’s publications over the last six-and-a-half years are in his own journal!
Back to the issue of glyphosate.
If the Glyphosate-human disease link is as likely and as important and alarming as Samsel and Seneff claim, why bury it in such an impactless journal?
Perhaps because the paper itself is a poster child for how to publish pseudoscience.
Since the Interdisciplinary Toxicology paper is essentially a clone of the Entropy paper, it makes the same mistake of misleading the reader to conclude that correlation implies causation–it does not. But what makes the paper believable to the nonscientist, yet worthy of a weeping face-palm by the scientifically literate, are the graphs. Here is one of them:
The sources of the data upon which the graphs in the paper are based (USDA:NASS; CDC) are not referenced in a way that they can be tracked down, and no citations for the data sources can be found in the Literature Cited section. If we look at the graph from the article that Mother Earth News celebrates, we see that the axes have been adjusted to show a “fit” that is nothing more than a spurious correlation. For this relationship to be even remotely meaningful, the exact same people who have been diagnosed with celiac disease have to be the ones eating the wheat upon which the glyphosate is applied. They’re not. The scale on the primary Y-axis has also been adjusted to make the correlation look nearly perfect. The figure caption is also suspicious. Most obviously, who is this Nancy Swanson person that prepared the figure (and other figures in the paper), and why isn’t she a coauthor? Nancy Swanson is a retired physicist who writes and promotes GMO horror stories, among other topics, and publishes as the Seattle GMO Examiner in examiner.com. The biased and misleading graphs alone, and their creator, turn what could be an interesting idea into complete nonsense.
In closing, the glyphosate-human toxicity question is an important one. However, the Entropy and Interdisciplinary Toxicology publications by Stephanie Seneff and Anthony Samsel do not establish any credibility to a possible link. The papers and their authors, in fact, completely backfire. Both papers are perfect examples pseudoscience, bad science, bias, and how not to do science. I wish it were this simple to show empirically, convincingly, and repetitively that glyphosate causes gluten intolerance and celiac disease. But biased and pseudoscientific papers are not the way toward an answer. If we value voters and politicians that are informed on important issues like human health, we cannot tolerate authors that prey on the scientific illiteracy of the general public. It is too easy today to make a claim look credible and evidence-based and then feed it to a public that is hungry for information but has no idea how to distinguish the good from the bad.
The immediate issue for me as a science teacher is that I have to take the time to help my students wade through the many questionable and pseudoscientific open access articles they find on Google Scholar just so they can make an evidence-based argument from which to launch their hypotheses and answer their research questions.