The reveal of sealed documents from agricultural corporation Monsanto in March 2017 left the medical world silent. After a ruling from San Francisco Judge Vince Chhabria in a civil suit regarding the development of non-Hodgkin’s lymphoma, the contents of the previously sealed documents shocked the nation.1
Later to be published in an article titled “The Monsanto Papers: Poisoning the Scientific Well,” the documents revealed “‘ghostwritten articles in toxicology journals, the creation of pseudo-academic websites, as well as countless accounts of collusion” with those in medicine, media, and even the Environmental Protection Agency, all to hide the fact that exposure to Roundup chemical glyphosate causes cancer.1-7
Editor’s note: A review of the court cases led the author to initiate a discussion about the impact of glyphosate later in this article.
What is Glyphosate?
Following the burst of interest surrounding this debacle, a resurgence of research closed in on glyphosate—the key ingredient in the Roundup herbicide that Monsanto (now owned by Bayer) both manufactures and modifies its seeds to resist. While the company offers other genetically modified crops (GMO), the ones most prevalent in the American diet are canola, corn, soybeans, and wheat.24 In the event that farmers spray Roundup to control other invasive species and weeds, it leaves the genetically modified crops — or Roundup Ready, as they are affectionately known — unharmed while preventing all other weeds from growing via protein inhibition technology.8
It is important to note that the term “genetically modified” in food labeling does not necessarily refer to glyphosate-resistant modifications. There are deviations in genetic modification that fortify nutrients into crops—such as corn—that have not only been proven to be safe but effective at eliminating micronutrient deficiencies in areas of poverty.9 Moreover, just because a seed is genetically modified to be resistant to glyphosate does not mean that the chemical glyphosate is present on the crops. It simply suggests that if the grower had to reach for an herbicide with a field of glyphosate-resistant crops, why would they reach for anything else?
As indicated in a 2019 article from Mutation Research, farmers themselves are at the greatest risk with high occupational exposure to glyphosate, raising the risk of cancer (non-Hodgkin’s lymphoma) by as much as 41%.7 However, the risk does not only lie in the administration of the herbicide. Glyphosate, which is the most widely used herbicide in the country, “can be detected in 50% of surface waters in the United States, as well as in soil, air, groundwater, and in our food.”3
Some fear that the creation of genetically modified crops may cause a dangerous gene flow among the genetically modified varieties and natural plants, creating unknown hybrids with unknown effects on ecology, bacterial populations, antibiotic resistance, or human systems.9
Does this sound unlikely? Not to Monsanto. In fact, Monsanto has been known to lodge lawsuits against farmers — hundreds of them — indicating that farms growing corn or soybeans within a certain geographic distance from genetically modified seeds would reasonably be subject to cross-pollination, therefore, indicating seed patent violations.10 Out of its 145 similar lawsuits to date, all have been won by the corporate giant.
The opposite has also been true. There have been farmers wanting to prevent the growth of modified seeds anywhere near their organic foods so as not to receive any unwanted cross-pollination. These lawsuits, however, were dismissed in federal court.10
Impact on Drinking Water
To determine the effect of drinking water containing the chemical, one 2019 study utilized rats and mice over the course of 72 weeks using water consumption as the method to introduce the chemical for scientific analysis.
While the article admits that the level of glyphosate utilized in the study was 15 times beyond that reasonably achieved in a dietary consumptive fashion, the result was notable. While it did not cause the development of multiple myeloma, a dangerous kind of white blood cell cancer, it did cause cancer to progress more rapidly than those not exposed to glyphosate.3
Another study in Frontiers in Genetics (2019) indicated interest in research regarding this chemical and breast epithelial cells to determine whether it amplified the expression of cancer.11 The study concluded that multiple risk factors, including the presence of glyphosate, may play more of a role in the metastatic behavior of breast cancer than previously thought, as the influence of endocrine pathways—namely, estrogen—is a commonly investigated link in the most up-to-date breast cancer research.11-14 Glyphosate has been documented to affect a variety of pituitary and endocrine functions ranging from disrupted male reproductive cells, sex hormone imbalances, to thyroid dysfunction.12-15
In the past few years, three separate juries found enough evidence to hold Roundup manufacturer and genetically modified seed giant Monsanto (Bayer) responsible for the development of non-Hodgkin’s lymphoma in civil suits. One lawsuit assigned $2 billion in punitive damages to the company.2
The New York Times reported, “Despite these rulings, some representatives from the EPA continue to deny that glyphosate has carcinogenic properties nor poses any risk to the public.”2 The most recent appeal of these rulings involves Monsanto’s unwavering relationship with the EPA, claiming that Monsanto could not be responsible for the lack of a carcinogen label on its product because the EPA never categorized glyphosate as a carcinogen.6 This to the opposition of the World Health Organization’s International Agency for Research on Cancer, which issued a statement in 2015 that “glyphosate is probably carcinogenic in humans.”1,4
While most studies these days are aimed at proving or disproving causation of cancer from the ingestion, inhalation, or transcutaneous exposure to glyphosate, one of the most widely documented side effects is chronic inflammation.16,17 Seemingly benign in comparison to cancer, exposure to glyphosate has been linked to lung inflammation such as in asthma, chronic allergies, as well as inflammation associated with metabolic disorders such as fatty liver disease, type 2 diabetes and obesity.16,17,22 With all of these articles pouring out in the last two years or so, many of them citing increases in inflammatory cytokines such as interleukins, tumor necrosis factor-alpha, and increases in neutrophils noted as a response to exposure to glyphosate, it has a dental hygienist’s interest piqued.16 Could this be affecting the mouth?
While research regarding gastrointestinal inflammation in response to exposure to glyphosate is sparse, there have been a few documented cases. One from Medicine in 2019 discusses a suicide attempt via ingestion of glyphosate.18 While the amount of ingested herbicide, in this case, is obviously excessive, it was noted that the ingredient is highly corrosive to the gastrointestinal mucosa and submucosa, especially at the pylorus.18 In milder cases, edema and erosion of the gastrointestinal structures are postulated to be outcomes; substantial gastric ulcers, gastric perforation and scarring expected in severe cases.18
This was confirmed by a review of 93 cases over a span of almost ten years in one specific hospital; “mild oral discomfort, erosion of the gastrointestinal tract, sore throat, and gastrointestinal hemorrhage” were all observed following ingestion of glyphosate.19
With about 10-20% of the population suffering from chronic gastrointestinal inflammation associated with irritable bowel syndrome, is it really that far of a leap to suggest that glyphosate-treated food—genetically modified corn syrup, corn starch, corn cereals, soymilk— that may have residual trace amounts of the chemical could be causing inflammation in the very region of the body that comes in closest contact with the ingredient: the mouth, the stomach, and the intestinal tract?18-20
Clinical Implications for Hygienists
Dental hygiene clinicians should be more aware of the potential effects of the herbicides used around the food that is available to patients. While there does not currently exist a body of literature surrounding the effect of glyphosate on oral mucosa nor bacteria, alterations in both would stand to be a logical hypothesis worth exploration.3,4,7,11,12,16-19
The first organ to come in contact with food that has been potentially treated with glyphosate is the mouth. It would be reasonable to suggest that inflammation in the mouth may be associated with or exacerbated by the consumption of these foods.16-20
Perhaps dietary counseling is not only indicated for those high-decay risk patients but for periodontal patients as well. Could a person’s level of oral inflammation potentially improve following a diet with total elimination of corn, soy, wheat, and canola oil products? Is it possible that glyphosate, an ingredient implicated in the immunosuppression related to white blood cell cancers, and tied to documented increases in inflammatory cytokines, could be a risk factor for periodontal disease?1,3,7,16,17
Despite the legal rulings, it is still difficult to believe that any study out there can definitively link one chemical to the development of a disease as poorly understood and multifactorial as cancer. To be able to control for every confounding factor in the development of the disease — genetic influences, nutrition, cortisol levels, exposure to household cleaning products, etc. — and proclaim with absolute certainty that there is a cause-and-effect relationship is nearly impossible.
Dentistry has been no stranger to the torch-and-pitchfork media, villainizing something as beneficial and as clearly proven as fluoride. Yet, it is our job as clinicians to be open to the idea that glyphosate could be a contributing factor. It could contribute to the development of malfunctions in our body’s natural defenses against pathogens by altering the function of lymphocytes.3,7 It could contribute to elevated levels of inflammatory cytokines, propagating the periodontal pathway of disease via interleukin activation and the release of tumor necrosis factor-alpha.16 It could potentially contribute to oxidative (free radical) damage that could play an accessory role in the development of oral cancer.7,12,21-23
The purpose of this article is not to assign fault to any one corporation nor any one ingredient, but to influence clinicians to think outside the box. As the world around us evolves and as science hones in on chemicals the average person is exposed to on a daily basis, we need to utilize our knowledge of disease to make sense of the information and to change our treatment modalities accordingly. Don’t wait for the clinical trial to come out 10 years from now to start connecting the dots.
Ask patients about their diets. Patients don’t understand words like “cytokines” and if we don’t fight for them—for better research, for more literature to understand the effects of what we put into our bodies—no one will.
Now Listen to the Today’s RDH Dental Hygiene Podcast Below:
- Hakim, D. Monsanto weed killer Roundup faces new doubts on safety in unsealed documents. The New York Times. 2017 Mar 14. Retrieved from https://www.nytimes.com/2017/03/14/business/monsanto-roundup-safety-lawsuit.html
- Cohen, P. $2 billion verdict against Monsanto is third to find Roundup caused cancer. The New York Times. 2019 May 13. Retrieved from https://www.nytimes.com/2019/05/13/business/monsanto-roundup-cancer-verdict.html
- Wang, L., Deng, Q., Hu H., et al. Glyphosate induces benign monoclonal gammopathy and promotes multiple myeloma progression in mice. Journal of Hematology and Oncology. 2019; 12: 70.
- IARC monograph on glyphosate. International Agency for Research on Cancer. World Health Organization. 2018. Retrieved from https://www.iarc.fr/featured-news/media-centre-iarc-news-glyphosate/
- McHenry, L. The Monsanto papers: poisoning the scientific well. International Journal of Risk and Safety in Medicine. 2018 June 4; 29: 193-205.
- Davidson, J. Trump’s EPA backs Bayer’s appeal in Roundup verdict appeal. EcoWatch. 2019 Dec 23. Retrieved from https://www.ecowatch.com/trump-epa-backs-bayer-2641674057.html
- Zhang, L., Rana, L., Shaffer, R., et al. Exposure to glyphosate-based herbicides and risk for non-Hodgkin lymphoma. A meta-analysis and supporting evidence. Mutation Research/Reviews in Mutation Research. 2019; 781: 186-206.
- Henderson, A., Gervais, J., Luukinen, B., et al. 2010. Glyphosate General Fact Sheet. National Pesticide Information Center; Oregon State University Extension Services. Retrieved from http://npic.orst.edu/factsheets/glyphogen.html
- Arjo, G., Capell, T., Matias-Guiu, X., et al. Mice fed on a diet enriched with genetically engineered multivitamin corn show no sub-acute toxic effects and no sub-chronic toxicity. Plant Biotechnology Journal. 2012 Aug 29; 10: 1026-1034.
- Harris, P. Monsanto sued small farmers to protect seed patents, report says. The Guardian. 2013 Feb 12. Retrieved from https://www.theguardian.com/environment/2013/feb/12/monsanto-sues-farmers-seed-patents
- Duforestel, M., Nadaradjane, A., Bougras-Cartron, G., et al. Glyphosate primes mammary cells for tumorigenesis by reprogramming the epigenome in a TET3-dependent manner. Frontiers in Genetics. 2019 Sep 27; 10(9): 885.
- Lucia de Liz Oliveira Cavalli, V., Cattani, D., Rieg, C., et al. Roundup disrupts male reproductive functions by triggering calcium-mediated cell death in rat testis and Sertoli cells. Free Radical Biology and Medicine. 2013 Dec; 65: 335-346.
- Seralini, G.E., Clair, E., Mesnage, R., et al. Republished study: long-term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize. Environmental Sciences Europe. 2014; 26(1): 14.
- Resnik, D. Retracting inconclusive research: lessons from the Seralini GM maize feeding study. Journal of Agricultural and Environmental Ethics. 2015 Aug; 28(4): 621-633.
- De Souza, S., Kizys, M., Da Conceicao, R., et al. Perinatal exposure to glyphosate-based herbicide alters the thyrotrophic axis and causes thyroid hormone homeostasis imbalance in male rats. Toxicology. 2017 Feb 15; 377: 25-27.
- Kumar, S., Khodoun, M., Kettleson, E., et al. Glyphosate-rich air samples induce IL-33, TSLP and generate IL-13 dependent airway inflammation. Toxicology. 2014 Nov 5; 0: 42-51.
- Pandev, A., Dhabade, P., Kumarasamy, A. Inflammatory Effects of subacute exposure to Roundup in rat liver and adipose tissue. Dose Response. 2019 Apr-Jun; 17(2).
- Luo, M., Lu, T., Li, F., et al. Surgical Treatment of Pyloric Stenosis caused by glyphosate poisoning. Medicine. 2019 Jul; 98(30); e16590.
- Talbot, A., Shiaw, M.H., Huang, J.S., et al. Acute poisoning with a glyphosate-surfactant herbicide (‘Roundup’): a review of 93 cases. Human and Experimental Toxicology. 1991 Jan; 10(1): 1-8.
- Lehrer, J., Lichtenstein, G. Irritable Bowel Syndrome. Medscape. 2019 Dec 11. Retrieved from https://emedicine.medscape.com/article/180389-overview
- Antioxidants and Cancer Prevention. National Cancer Institute. 2017 Feb 6. Retrieved from https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/antioxidants-fact-sheet
- Mesnage, R., Renney, G., Seralini, G. Multiomics reveal non-alcoholic fatty liver disease in rats following chronic exposure to an ultra-low dose of Roundup herbicide. Scientific Reports. 2017; 7: 39328.
- Marc, J., Mulner-Lorillon, O., Boulben S., et al. Pesticide Roundup provokes cell division dysfunction at the level of CDK1/cyclin B activation. Chemical Research in Toxicology. 2002 Mar; 15(3): 326-31.
- Agriculture seeds. Monsanto Company. 2002-2019. Retrieved from https://www.monsantoglobal.com/global/in/products/pages/seeds.aspx