The small organic chemical, glyphosate, kills many broadleaf plants and is the chief ingredient of the very popular herbicide, Roundup®, produced by the Monsanto Corporation. Glyphosate is used in agriculture to kill weeds and also for pre-harvesting applications to wheat. Its usage on farms rose dramatically when Monsanto also developed Roundup® Ready crop seeds (see: http://www.monsanto.com/products/pages/monsanto-agricultural-seeds.aspx ); these mutants of corn, soybeans, and other crops have resistance to higher levels of glyphosate that kill their nonresistant counterparts Today, (1) Roundup® and strains of crops more tolerant to glyphosate are in very widespread use on farms all over the world, (2) normal pollination by airborne dispersal easily results in crossbreeding of resistant and non-resistant strains, (3) widespread usage of Roundup® in modern agriculture means that resistant strains automatically spread and take over any neighboring fields originally planted with only non-resistant strains, and, (4) the amount of glyphosate-containing agricultural products consumed by humans is substantial and is increasing.
The first article in this series provided a general background for controversies involving scientists (see: Part I ). The second article discussed the ongoing controversy about global warming and climate change (see: Part II ). This essay examines the ongoing controversy about whether glyphosate is benign or harmful to humans.
How does glyphosate get inside humans?
Glyphosate enters human bodies via several different routes: (1) ingestion of agricultural crop products containing glyphosate due to treatment with Roundup®, (2) drinking of water having small or large glyphosate contents, (3) breathing of atmospheric glyphosate microparticulates due to its widespread dispersal during agricultural applications, (4) ingestion of farm aninals which ate corn or other plant material treated with Roundup®, and, (5) ingestion of bovine milk, chicken eggs, and other animal products.
Basically, everyone living on this planet now has glyphosate within their body. Monsanto originally performed short-term research studies showing that glyphosate has very low toxic effects upon humans. However, long-term research data for chronic exposures are missing. Very high levels of glyphosate inside human food sources mostly are being ignored by regulatory agencies, many farmers, and most scientists. The primary question for health researchers and clinical doctors is, “Does glyphosate have any toxic and pathological effects in humans?”. This is a very straightforward research question and should be readily answered by scientific investigations.
What does scientific research on glyphosate find about its safety?
An extensive examination of published biochemical investigations recently showed that glyphosate could have quite a few undesired consequences upon humans and mammals, aquatic organisms, and bacteria . The changes in metabolism caused by glyphosate affect cytochrome P450, enzymes, sulfate balance, amino-acid dynamics, and the human gut microbiome; these changes are alleged to be involved in such pathological states as Alzheimer’s disease, autism, breast cancer, developmental anomalies, irritable bowel syndrome, obesity, and vitamin-D deficiency . People already have been exposed to Roundup® for many years, but its causation of disease states remains uncertain; plausable associations alone are not sufficient to establish causality. Worrisome new research findings showing involvement of glyphosate in human pathology are disputed by Monsanto and some other scientists.
A good published, but retracted, experimental study by Séralini et al  investigated chronic toxicity in rats exposed to glyphosate in various forms and dosages. This professional research report aroused an amazing degree of controversy [3,4], resulting in empty disputes, personal attacks, and improper activities by the publishing journal . Regretably, that dispute includes documented examples where scientists associated with Monsanto have restricted publication of research manuscripts showing that glyphosate can be quite harmful to the health of humans and animals; this has caused accusations that some science journals are not honest, use double standards for review of manuscripts, and have become subordinate to commerce .
The United States Food and Drug Administration.
If Roundup® might be dangerous, why is it not being researched and regulated more? The United States Food and Drug Administration (FDA) is charged with monitoring and regulating public safety of all the many chemicals, foods, and materials used in our country ( http://www.fda.gov/Food/ ). Toxicologists working at the FDA investigated glyphosate toxicity and established that anything below a certain level is not harmful to humans. Toxicologists in other countries conducted similar evaluations to establish a safe level, but some of their approved values are smaller than that validated by the FDA. Certain countries even ban use of glyphosate and genetically-modified crops resistant to glyphosate. Nevertheless, millions of pounds of glyphosate now are used annually on farms around the globe .
Almost all Americans are totally reliant on the FDA to keep them safe from poisons and dangerous foods. What does the FDA say about the glyphosate controversy? The answer is “not much”, since their scientists apparently are not conducting all the needed measurements. Why have these not been conducted? Or, why were the needed assays indeed conducted, but the results are not released? Is Monsanto influencing risk assessment by the FDA?
Could human diseases be caused by glyphosate?
Several different disease states now are postulated to be caused directly or indirectly by glyphosate [e.g., 1]. Where the incidence of these pathological states has risen in time, data for the amount and distribution of glyphosate in people runs a closely parallel course. The health implications of the glyphosate controversy are very extensive; it has even been proposed that the problem associated with gluten in bread actually is a problem with its glyphosate content . Clearly, much more research is badly needed; despite the increasing association of glyphosate with pathology, definitive causality of human diseases by this chemical has not yet been proven.
Many glyphosate-containing weed-killers now are being marketed to farmers. These contain different additives (e.g., adjuvants, detergents, surfactants) that enhance the toxic effects of glyphosate upon plants. This enhancement is due to augmented absorption by agricultural plants, thereby giving humans eating them an increased dosage . The amount of glyphosate in foods also is increased by the fact that many farmers now are adding additional Roundup® to their crops to deal with the new presence of glyphosate-resistant weeds. Global governmental regulations of approved glyphosate levels have conveniently been raised by large amounts to handle this new situation . Thus, despite the increasing evidence suggesting that glyphosate could have some bad effects upon human health, people eat more and more Roundup® each and every year .
The controversy about the alleged human toxicity of glyphosate and Roundup® already is more than a decade old. Despite the suggested pathology, the amount of glyphosate eaten by humnans and accumulating inside them constantly increases . It is alarming that the potential public health disaster of chronic glyphosate toxicity is not being researched much more vigorously by scientists.
This ongoing controversy not only has scientists arguing with other scientists, but also has scientists disputing with a very large well-established commercial company. The scientific issues regarding glyphosate toxicity are rather straightforward, but the needed research studies are not being conducted; it is suspected that these investigations are being hindered by Monsanto’s total focus on business profits.
While this controversy drags on, what should people do? Foods now are grown by some farmers without using exposure to Roundup® and are becoming more readily available in grocery stores. As one researcher involved with the glyphosate controversy has advised, “Go organic!” .
 Samsel, A., and Seneff, S., 2013. Review. Glyphosate’s suppression of cytochrome P450 enzymes and amino acid biosynthesis by the gut microbiome: Pathways to modern diseases. Entropy 15:1416-1463.
 Séralini, G. E., Clair, E., Mesnage, R., Gress, S., Defarge, N., Melatesta, M., Hennequin, D., and de Vendômois, J. S., 2012. Retracted. Long term toxicity if a Roundup herbicide and a Roundup-tolerant genetically modified maize. Food and Chemical Toxicology 50:4221-4231.
 Séralini, G. E., Mesnage, R., Defarge, N., Gress, S., Hennequin, D., Clair, E., Malatesta, M., and de Vendômois, J. S., 2013. Answers to critics: why there is a long term toxicity due to NK603 Roundup-tolerant genetically modified maize and to a Roundup herbicide. Food and Chemical Toxicology 53:476-483.
 Robinson, C., and Latham, J., 2013. The Goodman affair: Monsanto targets the heart of science. Independent Science News, May 20, 2013. Available on the internet at: http://www.independentsciencenews.org/science-medical/the-goodman-affair-monsanto-targets-the-heart-of-science/ ).
 Bohn, T., and Cuhra, M. 2014. How “extreme levels” of Roundup in food became the industry norm. Independent Science News, March 24, 2014. Available on the internet at: http://www.independentsciencenews.org/news/how-extreme-levels-of-roundup-in-food-became-the-industry-norm/ .
 Seneff, S., 2014. Slide #48 from presentation on glyphosate hosted by the MIT and Wellesley Alumni Associations, April 28, 2014. Available on the internet at: http://people.csail.mit.edu/seneff/California_glyphosate.pdf .
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