Glyphosate Use and its Hazardous Effects

Authored by Juliana Josinsky

Art by Samantha Smith

TikTokers have gone viral with claims that they can travel to Europe, eat large amounts of pasta and feel perfectly fine while in America, they must follow a gluten-free diet to avoid gut issues. While this topic may seem like another viral TikTok trend without any scientific basis, there may actually be some truth to this phenomenon. Gluten is the group of proteins found in wheat that provides structure to grains [1]. About 25% of Americans eat a gluten-free diet even if it is not medically required for them to avoid gluten [1]. People often avoid gluten because they believe it lessens symptoms like bloating, inflammation, or even fatigue and abdominal pain [1]. However, it may not be the gluten molecule that contributes to these symptoms. It is possible that these symptoms and other hazardous health effects are the result of the ingestion of herbicides, chemicals sprayed on crops to control weed growth.

The rise of gluten avoidant individuals seems to coincide with the trend in the agricultural industry of using more herbicides. Globally, herbicide use has risen and the use of one herbicide in particular, glyphosate, has increased by almost 15 times due to the introduction of genetically modified crops that are glyphosate-tolerant in 1996 [2]. However, the increase in glyphosate use in recent years is mainly concentrated within the United States (US). The US used 72% of the global share of glyphosate from 2004 to 2014 [2]. In fact, glyphosate is the most widely used pesticide in the US [2]. 

Herbicides are sprayed on wheat, corn, soybeans, chickpeas, and many other crops in order to control weed growth and produce higher crop yields [3]. Glyphosate is so commonly used in the US because the Environmental Protection Agency (EPA) has most recently determined that there are no health risks from its current uses and no evidence that it causes cancer nor that more children are more sensitive to it [3]. However, the US EPA originally classified glyphosate as possibly carcinogenic to humans in 1985 based on their evaluation of tumor growth in mice [4]. After re-evaluation in 1991, the US EPA changed its classification to non-carcinogenic for humans [4]. 

Outside of the United States, there are more restrictions on the use of these herbicides due to conflicting findings by international health agencies. In 2015, the International Agency for Research on Cancer (IARC), a part of the World Health Organization (WHO), published a report classifying glyphosate as being probably carcinogenic to humans [5]. This classification was in part due to evidence that glyphosate can cause DNA and chromosomal damage in human cells, even though in bacteria DNA was not damaged [4]. However, in 2016, the IARC changed the results of their findings [4]. Due to the debate over glyphosate’s safety, many European nations use less of it than the US does. A European has an exposure level of 0.3 milligrams of glyphosate per kilogram of body weight while an American has an exposure level of 1.75 [6]. 

Glyphosate has been found to be absorbed into the body through foods, drinking water, and environmental exposure, particularly for farmers [7]. A systematic review examining the results of all the studies that measured glyphosate levels in humans showed that average glyphosate urinary levels were much higher in those who were exposed occupationally compared to the normal population [7]. The effects of this absorption and possible retention of residual glyphosate in humans are unknown.

A study conducted found that fish exposed to glyphosate developed digestive problems that resemble Celiac Disease symptoms [8]. It also determined that the symptoms of Celiac Disease coincide with the effects of glyphosate on the body. Celiac Disease is a chronic autoimmune disease where individuals have difficulty absorbing nutrients in their small intestine when they are exposed to the peptide gliadin, a component of gluten [9]. According to this study, glyphosate can cause imbalances in healthy or pathogenic gut bacteria, which is associated with Celiac Disease as well [8]. Glyphosate is known to inhibit cytochrome P450 enzymes, which are the same enzymes that are impaired due to Celiac Disease [8]. Glyphosate has a strong ability to chelate or bond to certain metals such as iron, cobalt, molybdenum, and copper, which are the same metals that are deficient in individuals with Celiac Disease [8]. Amino acid deficiencies associated with Celiac Disease also correspond to glyphosate’s ability to deplete these amino acids [8]. Based on the results of this study, it may be possible that glyphosate absorption and toxicity is contributing to a rise of symptoms that resemble Celiac Disease. 

Another study conducted by New York University (NYU) Langone's Hassenfeld Children's Hospital found that human patients had greater odds of developing Celiac Disease if they were exposed to specific persistent organic pollutants (POPs) which include glyphosate [9]. Since individuals with Celiac Disease must follow a gluten free diet, this study suggests a direct connection between increased exposure to glyphosate and increased gluten intolerance. However, this study was conducted with a small sample size and would need to be replicated in order to confirm the results [9]. Further examination of the current research is needed to determine how much glyphosate is retained by the body and its effects on gut health and cancer rates. However, since there is such debate over the safety and health consequences of glyphosate, it seems more logical to use other insecticides and methods of pest prevention. 

References:

1. Study concludes Americans self-diagnose to adopt gluten-free diets. Nebraska Today | University of Nebraska–Lincoln. (2020, November 20). Retrieved March 1, 2023, from https://news.unl.edu/newsrooms/today/article/study-concludes-americans-self-diagnose-to-adopt-gluten-free-diets/

2. Benbrook, C. M. (2016, February 2). Trends in glyphosate herbicide use in the United States and globally. Environmental sciences Europe. Retrieved March 1, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5044953/ 

3. Environmental Protection Agency. (2022, September 23). Glyphosate. EPA. Retrieved February 3, 2023, from https://www.epa.gov/ingredients-used-pesticide-products/glyphosate

4. IARC Monographs Volume 112: Evaluation of - world health organization. (2015, March 20). Retrieved March 5, 2023, from https://www.iarc.who.int/wp-content/uploads/2018/07/MonographVolume112-1.pdf 

5. Dixon, E. (2019, February 15). Common weed killer glyphosate increases cancer risk by 41%, study says. CNN. Retrieved March 5, 2023, from https://www.cnn.com/2019/02/14/health/us-glyphosate-cancer-study-scli-intl/index.html  

6. Americans at greater risk of glyphosate exposure than Europeans. Environmental Working Group. (2023, March 2). Retrieved March 2, 2023, from https://www.ewg.org/news-insights/news/americans-greater-risk-glyphosate-exposure-europeans  

7. Gillezeau, C., van Gerwen, M., Shaffer, R. M., Rana, I., Zhang, L., Sheppard, L., & Taioli, E. (2019, January 7). The evidence of human exposure to glyphosate: A Review. Environmental health : a global access science source. Retrieved February 1, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6322310/     

8. Samsel, A., & Seneff, S. (2013, December). Glyphosate, pathways to modern diseases II: Celiac sprue and gluten intolerance. Interdisciplinary toxicology. Retrieved March 2, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3945755/#:~:text=Fish%20exposed%20to%20glyphosate%20develop,of%20glyphosate%20on%20gut%20bacteria.    

9. Gaylord, A., Trasande, L., Kannan, K., Thomas, K. M., Lee, S., Liu, M., & Levine, J. (2020, May 11). Persistent organic pollutant exposure and celiac disease: A pilot study. Environmental Research. Retrieved February 3, 2023, from https://www.sciencedirect.com/science/article/pii/S0013935120303327?via%3Dihub