06
Dec
Prenatal and Early Life Exposure to Glyphosate Herbicides Induce Hormonal Effects Disrupting Sleep and Neurodegenerative Diseases
(Beyond Pesticides, December 6, 2023) A study published in Antioxidants finds prenatal and early life exposure, usually after birth (perinatal), to glyphosate-based herbicides (GBH) induce oxidative stress in the brain, causing damage and negatively affecting melatonin levels. Melatonin is a hormone responsible for regulating circadian rhythm to mitigate sleep disorders. Disruption of melatonin levels also has implications for the development of age-associated neurodegenerative diseases, as melatonin is a neuroprotector against neurodegenerative diseases associated with aging. Additionally, GBH can alter molecules in the pineal gland in the brain, resulting in neurodegenerative diseases like Alzheimer’s disease (AD) and Parkinson’s disease (PD).
Levels of inadequate sleep patterns are rising among the global population. Reports find variability in sleep duration results in higher rates of depression, anxiety, and fatigue. Since sleep is an essential factor in normal brain development, disturbance in sleep patterns, such as sleeping too much or too little, can result in long-term associations with the brain’s white matter integrity (responsible for age-dependent cognitive function). The study warns, “Since decreased levels of the important antioxidant and neuroprotector melatonin have been associated with an increased risk of developing neurodegenerative disorders, this demonstrates the need to consider the melatonin hormone system as a central endocrine-related target of glyphosate and other environmental contaminants.â€
The study’s researchers exposed pregnant and lactating rats to GBH via drinking water, explicitly exposing the test population from gestational day five to postnatal day 15. Researchers analyzed serum melatonin levels and changes in the striatum cells located in the brain among the offspring 90 days after their birth. The results find that serum melatonin levels decrease by 43 percent among adult offspring compared to control offspring. Exposure to GBH also induced oxidative stress in the brain, resulting in changes in the brain’s striatum, including a 45 percent increase in lipid peroxidation, a 39 percent increase in DNA/RNA oxidation, and an increase in protein levels of the antioxidant enzymes like superoxide dismutase, glutamate–cysteine ligase, and glutathione peroxidase.
Environmental contaminants like pesticides are ubiquitous in the environment, with 90 percent of Americans having at least one pesticide compound in their body. These pollutants have a global distribution, with evaporation and precipitation facilitating long-range atmospheric transport, deposition, and bioaccumulation of hazardous chemicals in the environment. Many of these chemical compounds remain in soils, water (solid and liquid), and the surrounding air at levels exceeding U.S. Environmental Protection Agency (EPA) standards. The increasing ubiquity of pesticides concerns public health advocates as current measures safeguarding against pesticide use do not adequately detect and assess total environmental chemical contaminants. Therefore, individuals will continuously encounter varying concentrations of pesticides and other toxic chemicals, adding to the body burden of harmful chemicals currently in use.
This study adds to global research supporting the link between pesticide exposure and sleep disorders. Exposure to medium and high levels of pesticides results in shortened sleep duration, poorer sleep quality, and insomnia. Therefore, pesticides can interrupt normal non-rapid eye movement (NREM) and rapid eye movement (REM) sleep patterns. REM sleep is active, meaning more brain activity occurs (e.g., dreaming) compared to NREM sleep, which can be the beginning of sleep, light sleep, or deep sleep. REM and NREM sleep is essential in childhood development, learning/memory, and immune system support. Thus, pesticide exposure interrupts these processes, leading to health issues. For example, REM sleep disorder can be a precursor to neurodegenerative diseases, such as Parkinson’s disease and types of dementia. Studies have shown that more than 50 to 80 percent of people with REM sleep behavior disorder go on to develop a neurodegenerative disorder year later or even decades.
This study is one of the first to investigate the effects of glyphosate on melatonin production. Endocrine-disrupting chemicals, like melatonin, generally disrupt because their molecular structure closely resembles molecules part of normal endocrine processes. These endocrine-disrupting chemicals can bind to the receptor sites for hormones, disrupting normal endocrine function. For example, a University of Buffalo study has linked carbamate pesticides to diabetes. Researchers discovered that the insecticides carbaryl and carbofuran were structurally similar enough to melatonin that they “showed affinity for†melatonin receptors and could potentially affect glucose homeostasis and insulin secretion.
In addition to this study, several studies demonstrate that glyphosate directly affects the brain and is detectable in the brain tissue of animals. For instance, glyphosate can cross the blood-brain barrier, and the endocrine-disrupting properties noted in this study can cause neurotoxicity. Considering early-life GBH exposure can cause persistent neuroendocrine deficits that may promote long-term oxidative brain damage, it is essential to mitigate exposure to GBH, especially since the herbicide is the most commonly used globally.
Humans spend approximately one-third of their lives sleeping, and some animals even more so, signifying how important sleep is for normal bodily function, health, and well-being. Various pesticide products act similarly or in conjunction with other chemical substances, simultaneously resulting in more severe health outcomes. Moreover, pesticides themselves can possess the ability to disrupt neurological function. Pesticides’ impact on the nervous system, including the brain, is hazardous, especially for chronically exposed individuals or during critical windows of vulnerability and development. Therefore, advocates urge that policies enforce stricter pesticide regulations and increase research on the long-term impacts of pesticide exposure. Beyond Pesticides tracks the most recent studies related to pesticide exposure through the Pesticide-Induced Diseases Database (PIDD). This database supports the clear need for strategic action to shift from pesticide dependency. For more information on the multiple harms that pesticides can cause, see PIDD pages on Brain and Nervous System Disorders, Learning/Developmental Disorders, Endocrine Disruption, Body Burdens, and other diseases.
Beyond Pesticides advocates for a precautionary approach to pest management in land management and agriculture by transiting to organic. Buying, growing, and supporting organic can help eliminate the extensive use of pesticides in the environment and from your diet. For more information on how organic is the right choice for consumers and the farmworkers who grow our food, see the Beyond Pesticides webpage, Health Benefits of Organic Agriculture.Â
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Antioxidants
