21
Dec
Low-Dose Chronic Glyphosate Exposure Increases Diet-Induced Non-Alcoholic Fatty Liver Disease
(Beyond Pesticides, December 21, 2023) A new study published in Environmental Toxicology and Pharmacology adds to prior research indicating glyphosate promotes the occurrence of nonalcoholic fatty liver disease (NAFLD) through diet by causing liver inflammation and oxidative stress. More importantly, the predisposition for NAFLD occurred at levels within toxicological limits, which are doses of glyphosate classified as causing no adverse effects or No Observed Adverse Effect Level (NOAEL). NAFLD is a condition that causes swelling of the liver and can eventually lead to cirrhosis, cancer, or liver failure. This study highlights the Westernized diet (WD), comprised of foods enriched in saturated fats, cholesterol, and simple carbohydrates (e.g., fructose, glucose, and sucrose), plays a role in the nearly 40 percent increased risk of NAFLD. Although glyphosate disrupts gut microbes and induces liver inflammation, oxidative stress, and fatty acid levels that promote NAFLD, the combination of WD and glyphosate reduces the threshold risk for NAFLD development.
NAFLD is a growing worldwide epidemic, becoming the most prevalent form of liver disease and impacting at least 25 percent of the globe. Therefore, studies like this shed light on how diet and chemical exposure can work synergistically (together) to exacerbate disease risk.
The study evaluates whether choric (long-term) glyphosate exposure at the NOAEL or lower promotes the occurrence of diet-induced NAFLD. Over six months, researchers fed mice a Westernized diet consisting of high-calorie, high-sugar, high-fat foods with a high-sugar liquid while the control mice ate a balanced diet. The researchers also exposed the mice to the lowest dose of glyphosate (under the acceptable daily intake representing the estimated human environmental exposure) and another amount below or within the NOAEL. Lastly, research collected blood samples and liver tissue to evaluate the morphological, biochemical, and transcriptomic changes. Although WD induces obesity, high cholesterol, and glucose intolerance (as seen in diabetes), glyphosate did not exacerbate these risks. However, glyphosate did increase the rate (upregulation) of 212 genes associated with oxidative stress and inflammation in the liver while downregulating 731 genes related to cell division.
Glyphosate is the most commonly used active ingredient worldwide, appearing in many herbicide formulas, including Bayer’s (formerly Monsanto) Roundup.® The use of this chemical has been increasing since the inception of crops genetically modified to tolerate glyphosate over two decades ago. Glyphosate is often promoted by industry as a “low toxicity†chemical and “safer†than other chemicals, yet it has been shown to have detrimental impacts on humans and the environment. The toxic herbicide readily contaminates the ecosystem, with residues pervasive in food and water commodities. In addition to this study, decades of accumulated scientific literature commonly associates glyphosate with human, biotic, and ecosystem harm. Thus, glyphosate has been the subject of extensive controversy about its safety for humans, nonhuman organisms, and ecosystems. For instance, the presence of glyphosate in human bodies has risen dramatically during the past three decades. Research at the University of California San Diego found that, between two data collection periods (1993–1996 and 2014–2016), the percentage of people testing positive for the presence of glyphosate (or its metabolites) in urine rose by an average of 500 percent, peaking at 1,208 percent. Today, four out of five U.S. individuals over six years old have detectable levels of glyphosate in their bodies, with adolescents having higher bodily concentrations of glyphosate than adults. Glyphosate exposure has implications for the development of various health anomalies, including the distortion of DNA function, leading to several chronic diseases like cancer, Parkinson’s disease, metabolic disorders, gut dysbiosis, nervous system disorders, and neurodevelopment disorders like autism. In recent years, numerous lawsuits have targeted Monsanto (now Bayer), which contains glyphosate, alleging that the herbicide contributes to the plaintiffs’ cancers. Therefore, advocates say that it is crucial to comprehend the full spectrum of glyphosate’s effects on human health, from its potential carcinogenicity to its neurological and emotional ramifications.
Although the U.S. Environmental Protection Agency (EPA) classifies glyphosate herbicides as “not likely to be carcinogenic to humans,†stark evidence demonstrates links to various cancers, including non-Hodgkin lymphoma. For instance, the International Agency for Research on Cancer (IARC) has classified the chemical as a probable carcinogen or cancer-causing chemical. EPA’s classification perpetuates adverse impacts, especially among vulnerable individuals, like pregnant women, infants, children, and the elderly. Therefore, Beyond Pesticides has reported on EPA’s ongoing failures to protect people and the environment from glyphosate-based herbicide (GBH) compounds. Additionally, glyphosate’s ubiquity threatens 93 percent of all U.S. endangered species, resulting in biodiversity loss and ecosystem disruption (e.g., soil erosion, loss of services, and trophic cascades). Moreover, chemical use has been increasing since the inception of crops genetically modified to tolerate glyphosate. Not only do health officials warn that continuous use of glyphosate will perpetuate adverse health and ecological effects, but that use also highlights recent concerns over antibiotic resistance. This increase in resistance is evident among herbicide-tolerant GE crops, including seeds genetically engineered to be glyphosate-tolerant.
Previous research confirms what this study finds, that low doses of glyphosate exposure have implications for fatty liver disease. A 2015 study found that chronically exposing rats to ultra-low amounts of glyphosate in drinking water results in tissue and organ damage, including changes to gene expression within the liver and kidneys. A 2017 study, which also fed minuscule doses of glyphosate weed killer to rats, found an increased likelihood that exposed animals would develop nonalcoholic fatty liver disease. Roundup formulations can also induce a dose-dependent formation of DNA adducts (altered forms of DNA linked to chemical exposure, playing a pivotal role in chemical carcinogenesis) in the kidneys and liver of mice. While the study notes glyphosate did not influence obesity-induced NAFLD through high cholesterol, glucose intolerance, fat retention, and liver scarring, mechanisms that promote NAFLD still include oxidative stress and inflammation. This study suggests that glyphosate exposure upregulates oxidative metabolism, causing mitochondrial disruption and oxidative stress. Additionally, the study indicates lipid peroxidation (degradation of lipids) in the liver may play a role in upregulating proinflammatory proteins (cytokines) that play a role in inflammatory response. These two processes from glyphosate exposure can promote the risk of NAFLD in conjunction with WD.
Health officials estimate about 100 million individuals in the U.S. have NAFLD, with NAFLD being the most common liver disease among children. Cases of NAFLD have doubled over the past 20 years. Therefore, it is essential to mitigate preventable exposure to disease-inducing pesticides. For more information about pesticides’ effects on human and animal health, see Beyond Pesticides’ Pesticide-Induced Diseases Database, including pages on immune system disorders (e.g., hepatitis [liver condition], cancer (including lymphoma), and more.
One way to reduce human and environmental contamination from pesticides is to buy, grow, and support organic. Numerous studies show that switching to an organic diet can rapidly and drastically reduce the levels of synthetic pesticides in one’s body. A 2020 study found a one-week switch to an organic diet reduced an individual’s glyphosate body burden by 70 percent. Furthermore, given the wide availability of non-pesticidal alternative strategies, these methods can promote a safe and healthy environment, especially among chemically vulnerable individuals or those with health conditions. For more information on why organic is the right choice for consumers and the farmworkers that grow our food, see the Beyond Pesticides webpage, Health Benefits of Organic Agriculture.
Moreover, Beyond Pesticides provides tools, information, and support to take local action: check out our factsheet on glyphosate/Roundup and our report, Monsanto’s Roundup (Glyphosate) Exposed. Contact us for help with local efforts and stay informed of developments through our Daily News Blog and our journal, Pesticides and You. Additionally, check out Carey Gillam’s talk on Monsanto’s corruption involving glyphosate/Roundup at Beyond Pesticides’ 36th National Pesticide Forum.
Please see the petition to remove glyphosate from the market submitted to EPA by the Center for Food Safety on behalf of Beyond Pesticides, Farmworker Association of Florida, Organización en California de Lideres Campesinas, Alianza Nacional de Campesinas, and the Rural Coalition.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
