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Story at a glance:
- Chlorpyrifos exposure during pregnancy causes lasting brain damage in children after birth, including thicker cortex regions, reduced white matter and impaired fine motor skills development.
- Prenatal pesticide exposure triggers neuroinflammation and oxidative stress, creating a cycle of mitochondrial damage that reduces blood flow and neuronal density in developing brains.
- Female babies show higher vulnerability to chlorpyrifos effects, experiencing more sleep apnea, breathing problems and elevated inflammatory molecules in brain tissue than males.
- Pesticide exposure alters gene expression through epigenetic changes, permanently affecting how the brain responds to stress, inflammation and memory formation throughout life.
- Strategies to protect your health include filtering drinking water, exercising regularly, improving indoor air quality and choosing organic produce to reduce pesticide exposure.
Pesticides are widely used today in conventional agriculture to eliminate insects that infect crops, and one of the most widely used chemicals is chlorpyrifos. It was introduced to the American public in 1965 by the Dow Chemical Company.
But as decades passed, a growing body of evidence came out showing the side effects of this toxin, leading to a proposed ban at the federal level in 2017. However, it still hasn’t taken effect, leading to state governments enacting their own measures.
Despite the scientific pushback, chlorpyrifos remains widespread in agriculture. Now, research is showing that even unborn children who are exposed to it via their mother will develop neurological problems down the line.
How pesticides alter children’s brain development
A study published in JAMA Neurology looked at how prenatal exposure to chlorpyrifos affects the brains of children as they grow. The participants were school-aged children whose mothers had measurable levels of chlorpyrifos in their blood during pregnancy.
Advanced brain scans and behavioral tests were used to uncover whether exposure early in life has lasting consequences.
For the analysis, researchers compared children with higher exposure levels to those with lower ones, assessing both the structure of their brains and their performance on tasks related to motor skills.
Chlorpyrifos causes changes in brain anatomy
Fetuses exposed to higher levels of this pesticide had thicker regions of the brain cortex, reduced white matter and lower blood flow to key brain areas once they were born and grew up.
Digging deeper into the findings, the thickness of the cortex was not uniform across the brain. Specific regions in the frontal and temporal lobes, along with areas in the posterior-inferior cortex, were thicker in children with higher prenatal exposure.
While that might sound positive at first glance since “thicker” can imply “stronger,” the reality is very different.
In a developing brain, a thicker cortex in the wrong locations signals disrupted pruning, the process by which unnecessary brain connections are trimmed away to make room for efficient communication between neurons. This disruption is linked to poorer cognitive and motor outcomes later in life.
White matter mass is another concern
White matter is made up of bundles of nerve fibers coated with myelin, which allows fast transmission of signals. Considering this, children exposed to more chlorpyrifos had reduced volumes of local white matter in the same cortical regions that appeared abnormally thick.
Fewer or weaker white matter connections mean slower communication across brain areas, which explains why these children showed measurable deficits in motor speed and planning. Translated to real life, difficulties with tasks like writing, buttoning clothes or performing coordinated movements in sports are affected.
Blood flow and neuronal density were also reduced
Lower blood flow in the brain means less delivery of oxygen and nutrients, both of which are required for proper growth. In the study, reduced neuronal density suggests that there are simply fewer working brain cells in certain regions.
Taken together, these factors paint a picture of a brain that is structurally compromised and less capable of supporting normal cognitive and motor development.
Fine-motor speed is affected
Children with higher exposure to chlorpyrifos struggled with coordination. For context, fine motor skills involve precise movements like using a pencil or cutting with scissors, while motor programming refers to the brain’s ability to plan and execute sequences of actions. Both are necessary for learning and independence.
Oxidative stress and neuroinflammation go hand in hand
Chlorpyrifos has been shown to trigger oxidative stress. In the developing brain, where cells are rapidly dividing and wiring up new networks, these two factors have a significant impact.
“Inflammation and oxidative stress during fetal brain development impair mitochondrial functioning, which in turn produces more inflammation and oxidative stress, creating a vicious cycle of inflammation and metabolic dysfunction,” the researchers said.
“Enduring mitochondrial damage would account for widespread blood flow reductions observed across all three exposures, and it would be consistent with the lower neuronal density detected in deep white matter.”
The research showed that neurological, metabolic and mitochondrial problems clustered together in children who had higher exposures. It wasn’t only one issue in isolation — it’s a cascade of biological disruptions that reinforced each other.
Breathing problems and brain inflammation persist after early pesticide exposure
In an animal study published in PLOS One, researchers investigated how a mother’s chlorpyrifos exposure during pregnancy and breastfeeding leaves behind long-lasting effects on breathing during sleep and brain health of her offspring.
The team designed the study by dosing mother mice with chlorpyrifos from conception through weaning. The offspring themselves were never given the pesticide directly, which allowed them to test whether early-life exposure alone could disrupt brain and body function into adulthood.
Once the offspring reached 17 to 18 weeks of age, both male and female mice were monitored for two full days using electrodes to record brain activity during sleep and special chambers to measure breathing patterns.
The study produced worrying results
Adult offspring exposed before birth showed higher rates of abnormal breathing events, including more sighs (large, irregular breaths) and more sleep apneas, which are pauses in breathing while asleep. The effects were strongest in female offspring.
Women are at higher risk
In relation to the point above, researchers noted that the impact was much greater in females. This sex-specific effect suggests that hormonal and genetic differences interact with pesticide exposure to magnify harm.
A closer look at the breathing changes
The sleep apneas were not rare or mild — they occurred at significantly higher rates compared to controls. Normally, as rodents grow from juveniles to adults, the frequency of sleep apneas decreases.
In exposed mice, this protective reduction did not happen. In other words, early chlorpyrifos exposure blocked the natural improvement in breathing stability that usually comes with maturation.
Effects of chlorpyrifos on brain health
Researchers also analyzed tissue from the hippocampus, a brain region central to memory and stress regulation.
They found that female offspring exposed to chlorpyrifos before birth had higher levels of inflammatory molecules called cytokines, including IL-6 and tumor necrosis factor-alpha (TNF-α), and lower activity of protective genes called peroxisome proliferator-activated receptors (PPARs).
For context, cytokines are signaling proteins that trigger immune responses, and when chronically elevated in the brain, they create neuroinflammation. This damages neurons and disrupts how brain networks communicate, while lower PPAR activity means fewer brakes are applied to these damaging processes.
Pesticides affect gene expression
The researchers examined the genes that act as epigenetic regulators, which are biological switches that control how other genes turn on or off.
Two such genes, KDM5C and KDM6B, which are responsible for removing chemical marks on histones (proteins that package DNA), were significantly reduced in female offspring exposed to chlorpyrifos.
In essence, changes in histone regulation alter how entire sets of genes function, which means these epigenetic changes have the capability to permanently shift how the brain responds to stress, inflammation and even memory formation.
How chlorpyrifos exerts its toxic effects
Once inside the body, it metabolizes into CPF-oxon, a compound that powerfully blocks acetylcholinesterase (AChE), the enzyme that normally breaks down acetylcholine, which is a neurotransmitter that plays a central role in regulating breathing rhythm, sleep cycles and attention.
With AChE blocked, acetylcholine builds up and overstimulates the nervous system, especially in brain areas that coordinate breathing.
How to protect yourself and your family from pesticides
The findings are clear — exposure to pesticides is a hidden danger that eventually affects your child’s brain development, but that’s not all. Research shows that pesticides can cause health problems for people of all ages.
Thus, your priority is to lower pesticide exposure in your daily environment and to support your body’s natural ability to process and remove toxins. Here are my recommendations:
1. Filter your drinking water — Pesticides can easily find their way into your drinking supply. That said, investing in a high-quality filter gives you a reliable way to remove contaminants before they ever touch your lips. Preferably, install filters at the beginning and end points of your home.
A thorough filtration system is ideal because it also removes toxins from your shower. That’s because your skin also absorbs water, aside from what you drink.
2. Exercise regularly — Getting regular movement isn’t only about boosting your fitness. In a previous article, I noted how sweating is one of the best ways to help clear toxins from your body.
When you sweat, you push harmful chemicals out through your skin. To maximize results, I recommend that you engage in high-intensity exercise limited to 75 minutes a week only. If you go for longer than that, you risk losing the longevity benefits that exercise provides.
Essentially, medium-intensity exercise is the best way to stay fit, as it can’t be overdone. To understand the science behind this, read “Nailing the Sweet Spots for Exercise Volume.”
3. Improve indoor air quality — Pesticides are not only found in the produce you eat — they also drift through the air, drifting into your home and landing on surfaces.
To mitigate this problem, I recommend using air purifiers with high-efficiency particulate air (HEPA) filters and cleaning your home frequently with nontoxic methods help reduce indoor dust buildup.
If you find yourself living near a farm or business that uses pesticides, I recommend keeping your windows closed during peak hours to prevent toxins from entering.
4. Choose organic produce whenever possible — Fruits and vegetables are an important part of supporting optimal health, but the majority of them are sprayed with chemicals that eventually build up in your system.
By purchasing certified organic options, especially for produce that your children eat often, you’re cutting down on one of the main ways this pesticide enters their system.
Even swapping out just the foods you and your family eat the most — like apples, strawberries or leafy greens — makes a measurable difference in exposure. In the next section, I’ll share places where you can buy clean, healthy produce.
Where to find high-quality, organic produce
If you live in a dense, urban location in the U.S. that doesn’t have any local farmers markets, don’t worry. There are plenty of ways to connect with reputable organic farmers who employ regenerative agricultural practices, so you can still purchase their products. Below is a list of websites I recommend:
- American Grassfed Association — The goal of the American Grassfed Association is to promote the grass-fed industry through government relations, research, concept marketing, and public education. Their website also allows you to search for AGA-approved producers certified according to strict standards that include being raised on a diet of 100% forage, raised on pasture and never confined to a feedlot, never treated with antibiotics or hormones, born and raised on American family farms.
- EatWild.com — EatWild.com provides lists of farmers known to produce raw dairy products as well as grass-fed beef and other farm-fresh produce (although not all are certified organic). Here you can also find information about local farmers markets, as well as local stores and restaurants that sell grass-fed products.
- Weston A. Price Foundation — Weston A. Price has local chapters in most states, and many of them are connected with buying clubs in which you can easily purchase organic foods, including grass-fed raw dairy products like milk and butter.
- Grassfed Exchange — The Grassfed Exchange has a listing of producers selling organic and grass-fed meats across the U.S.
- Local Harvest — This website will help you find farmer markets, family farms and other sources of sustainably grown food in your area, where you can buy produce, grass-fed meats and many other goodies.
- Farmers Markets — A national listing of farmers markets.
- Eat Well Guide — Wholesome Food from Healthy Animals — The Eat Well Guide is a free online directory of sustainably raised meat, poultry, dairy and eggs from farms, stores, restaurants, inns, hotels and online outlets in the U.S. and Canada.
- Community Involved in Sustaining Agriculture — is dedicated to sustaining agriculture and promoting the products of small farms.
- The Cornucopia Institute — The Cornucopia Institute maintains web-based tools rating all certified organic brands of eggs, dairy products and other commodities, based on their ethical sourcing and authentic farming practices, separating concentrated animal feeding operation “organic” production from authentic organic practices.
- RealMilk.com — If you’re still unsure of where to find raw milk, check out Raw-Milk-Facts.com and RealMilk.com. They can tell you what the status is for legality in your state and provide a listing of raw dairy farms in your area. The Farm to Consumer Legal Defense Fund also provides a state-by-state review of raw milk laws. California residents can also find raw milk retailers using the store locator available at RAW FARM.
FAQs about chlorpyrifos exposure
Q: What is chlorpyrifos and why is it a concern?
A: Chlorpyrifos is a pesticide introduced in 1965 by Dow Chemical Co. and widely used in agriculture to control insects. Despite a proposed federal ban in 2017 due to mounting evidence of health risks, it is still commonly applied. Research now shows that prenatal exposure can cause long-term neurological damage in children.
Q: How does chlorpyrifos affect children’s brain development?
A: Studies reveal that prenatal exposure alters brain anatomy, including abnormal cortical thickness, reduced white matter and impaired blood flow. These changes interfere with neuronal pruning, communication between brain regions and fine-motor skills, leading to developmental and cognitive challenges.
Q: What are the long-term health effects of early chlorpyrifos exposure?
A: Beyond brain structure changes, exposure leads to oxidative stress, neuroinflammation and mitochondrial dysfunction. A related study published in PLOS One also found that offspring exposed before birth experienced abnormal breathing patterns, sleep apnea and higher neuroinflammation, particularly in females, suggesting sex-specific vulnerability.
Q: How does chlorpyrifos disrupt biological systems?
A: Chlorpyrifos is metabolized into CPF-oxon, a compound that blocks acetylcholinesterase, which is the enzyme that regulates acetylcholine. This causes overstimulation of the nervous system, impairing breathing rhythms, sleep cycles and motor coordination. It also alters gene expression and epigenetic regulation, leading to lasting impacts on stress, memory and brain health.
Q: What steps can families take to reduce pesticide exposure?
A: Here are four strategies to protect you and your family’s health:
- Filtering water with high-quality home systems.
- Exercising regularly helps detox through sweating.
- Improving indoor air quality using high-efficiency particulate air (HEPA) filters and wiping surfaces with nontoxic cleaning products.
- Choosing organic produce, especially for children.
Originally published by Dr. Joseph Mercola.
