31
Aug
Study Finds Glyphosate Exposure Among the General Population Poses a Risk to Neurological Health
(Beyond Pesticides, August 31, 2023) A study published in Environmental Research finds glyphosate levels in the body adversely affect neurological health. Specifically, oral intake (e.g., eating contaminated foods), inhalation, and dermal exposure to glyphosate lowered cognitive function scores, heightened likelihood of severe depressive symptoms, and impaired auditory (hearing) function. Thus, this study provides some of the first evidence linking glyphosate exposure to specific neurological health outcomes among the general U.S. population, indicating the need for further studies on mechanisms driving neurotoxicity and the medical significance over time. Although this study is among the first to highlight specific neurological effects from glyphosate exposure among the general population, this study is not the first to identify potential neurotoxicity from glyphosate exposure. (Previous research cited below.)
The ubiquity of glyphosate uses in agriculture—which leaves residues of the toxic chemical in food—and in public areas (e.g., parks, and walkways) may mean that exposures to it represent a significant risk factor for the disease. Glyphosate is already implicated or proven in developing numerous health anomalies, including cancer.
The neurological system, including the brain, spinal cord, and a vast network of nerves and neurons, is responsible for many bodily functions—from sensation to movement. However, pesticides play various roles in causing or exacerbating negative health outcomes like neurotoxic effects and chemical damage to the nervous system. The impacts of pesticides on neurological function are hazardous, especially for chronically exposed individuals (e.g., farmworkers) or during critical windows of vulnerability and development (e.g., childhood, pregnancy). Mounting evidence over the past years shows that chronic exposure to sublethal (low) levels of pesticides adversely affects the central nervous system (CNS) and neural receptors, such as connections between nerves, the brain, enzymes, and DNA. Specifically, researchers identify agricultural chemical exposure as a cause of many adverse CNS impacts and neurological diseases, including Alzheimer’s, amyotrophic lateral sclerosis (ALS), and Parkinson’s disease. Therefore, it is essential to understand how toxic chemical exposure can potentially damage neurological function, ultimately leading to more severe health anomalies among future generations.
The study notes, “While the directionality and clinical significance of these associations require further investigation, our findings underscore the need for continued research on the potential neurological effects of glyphosate exposure in adults. Such research can inform public health policy and regulatory decisions regarding glyphosate use and ultimately contribute to the protection of human health.”
Although occupational studies find links between neurological impairment and glyphosate exposure, much less research focuses on general population exposure as the general public still encounters glyphosate exposure through various mediums (e.g., contaminated food and water, proximity to pesticide-treated areas). Using data from the 2013–2014 National Health and Nutrition Examination Survey (NHANES), glyphosate exposure (through urinary sample analysis) and cognitive function, depressive symptoms, disability, and neurological medical conditions among the U.S. population. The study examines 1523 individuals aged 18–80 years old. The study finds 80.4% of participants have detectable levels of glyphosate in their urine. The analysis finds a significant association between urinary glyphosate levels and memory impairment as established by the Consortium to Establish a Registry for Alzheimer’s Disease Word List Memory Test (CERAD-WLT). Regardless of glyphosate levels, the presence of glyphosate in urine indicates an increased risk for severe depressive symptoms. Lately, this study finds serious hearing difficulties arose in individuals with higher urinary glyphosate concentrations.
Glyphosate is the most commonly used active ingredient worldwide, appearing in many herbicide formulations and readily contaminates soil, water, food, and other resources. Decades of extensive glyphosate herbicide use (e.g., Roundup) have put human, animal, and environmental health at risk. Four out of five U.S. individuals over six years of age have detectable levels of glyphosate in their bodies. Exposure to glyphosate has implications for the development of various health anomalies, including cancer, Parkinson’s disease, developmental and birth disorders, and autism. 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. EPA’s classification perpetuates adverse impacts, especially among vulnerable individuals, like pregnant women, infants, children, and the elderly. 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. Therefore, as glyphosate persists in the environment through continuous use, threats to human, animal, and environmental well-being will only grow.
Regarding other findings linking glyphosate to neurotoxic effects, a 2022 Arizona State University (ASU) study found that glyphosate successfully crosses the blood-brain barrier, accumulating in the brain in a dose-dependent manner. Glyphosate accumulation in brain matter has the potential to elevate the expression of TNFα and accumulation of soluble beta-amyloid (Aβ) proteins commonly present in immune, inflammatory, and neurodegenerative diseases like Alzheimer’s disease (AD). Thus, the ASU study provides a potential mechanism and medically significant outcomes associated glyphosate and neurological impairment that researchers can apply to the current study to determine how glyphosate induces neurotoxicity.
The detectable levels of glyphosate in over 80 percent of patients raises concerns over unaccounted exposure sources since the elimination half-life of glyphosate is between 5.5 and 10 hours. Additionally, this study highlights that aminomethylphosphonic acid (AMPA), the metabolite of glyphosate, is commonly present in soil through degradation. However, AMPA is just as toxic as glyphosate and poses the same health risks. Therefore, transitioning pest management—in agriculture, land management, and household and personal care contexts—to nontoxic and organic approaches to eliminate ecosystem contamination is the critical step to take to protect the health and sustainability of all on Earth.
There is a lack of complete understanding of the etiology of pesticide-induced diseases, including predictable lag time between chemical exposure, health impacts, and epidemiological data. Pesticides themselves can possess the ability to disrupt neurological function. Pesticides’ impact on the nervous system, including the brain, are especially of concern for chronically exposed individuals or during critical windows of vulnerability and development. Therefore, studies related to pesticides and neurological disorders can help scientists understand the underlying mechanisms that cause neurodegenerative diseases. Although occupational and environmental factors, like pesticide exposure, adversely affect human health, regulatory reviews are plagued by numerous limitations in defining real-world poisoning, as captured by epidemiologic studies in Beyond Pesticides’ Pesticide-Induced Diseases Database (PIDD) and Daily News Blog. The adverse health effects of pesticides, exposure, and the aggregate risk of pesticides showcase a need for a precautionary approach to the regulation of pesticides as more precise research is conducted on occupational and residential pesticide exposure—allowing more complete determinations. Existing information, including this study, supports the clear need for a strategic shift away from pesticide dependency. For more information on the effects of pesticide exposure on neurological health, see Beyond Pesticides’ PIDD pages on brain and nervous system disorders, including dementia-like diseases, such as Alzheimer’s, and other impacts on cognitive function.
Organic agriculture represents a safer, healthier approach to crop production that does not necessitate pesticide use. Beyond Pesticides encourages farmers to embrace regenerative, organic practices, consumers to purchase organic, and gardeners and municipalities to adopt organic land management practices. A complement to buying organic is contacting various organic farming organizations to learn more about what you can do.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Environmental Research
