If you are worried about Parkinson’s disease and want to reduce your risk through diet, start by buying organic versions of green beans, spinach, bell peppers, kale, and strawberries. These items top the Environmental Working Group’s 2025 Dirty Dozen list, and the pesticides found on them include chemicals that researchers have directly linked to the destruction of dopamine-producing neurons in the brain. A January 2026 UCLA Health study found that long-term exposure to just one of these chemicals, chlorpyrifos, was associated with more than a 2.5-fold increased risk of developing Parkinson’s disease.
The connection between pesticides and Parkinson’s is no longer speculative. Multiple large-scale studies now show that people exposed to certain agricultural chemicals face up to double the risk of developing the disease, and some specific pesticides push that figure even higher. This article breaks down which pesticides pose the greatest neurological threat, which fruits and vegetables carry the heaviest pesticide loads, where you can save money by buying conventional, and what practical steps you can take to protect your brain health without overhauling your entire grocery budget.
Table of Contents
- How Strong Is the Link Between Pesticides in Produce and Parkinson’s Risk?
- Which Pesticides Are Most Dangerous for Brain Health?
- The 2025 Dirty Dozen and What It Means for Neurological Health
- Where to Save Money with the Clean Fifteen
- Genetic Vulnerability and Who Should Be Most Concerned
- Pesticides and Developing Brains in Children
- Where Pesticide Regulation Is Heading
- Conclusion
- Frequently Asked Questions
How Strong Is the Link Between Pesticides in Produce and Parkinson’s Risk?
The evidence is extensive and comes from multiple research angles. The Agricultural health Study, which followed roughly 90,000 licensed pesticide applicators, found through its FAME Study component that participants who developed Parkinson’s were 2.5 times more likely to have used rotenone or paraquat. These are not obscure chemicals. Paraquat remains one of the most widely used herbicides worldwide, and rotenone, though now restricted in the United States, was long used as a garden insecticide and fish poison. Rotenone inhibits mitochondrial complex I, while paraquat causes oxidative stress, and both mechanisms destroy the dopaminergic neurons whose loss defines Parkinson’s disease. The UCLA chlorpyrifos study, published in Molecular Neurodegeneration in January 2026, adds another dimension.
Researchers analyzed 829 people with Parkinson’s and 824 controls and found that long-term residential exposure to chlorpyrifos more than doubled the risk of developing the disease. Laboratory experiments showed why: the pesticide damages dopamine-producing neurons by disrupting autophagy, the cellular process that clears out damaged proteins. When this cleanup system fails, toxic protein aggregates build up, a hallmark of Parkinson’s pathology. Although residential use of chlorpyrifos was banned in 2001 and agricultural use was restricted in 2021, it is still used on many crops in the United States and remains widely applied globally. What makes the research particularly concerning is the dose-response relationship. A study on organophosphate pesticides found that ambient exposure to individual organophosphates increased Parkinson’s risk, and that exposure to increasing numbers of different organophosphates was associated with progressively elevated risks. This was the first study to demonstrate this cumulative effect in a human population, and it suggests that the cocktail of pesticides found on conventional produce may be more dangerous than any single chemical alone.
Which Pesticides Are Most Dangerous for Brain Health?
In 2023, UCLA and Harvard researchers conducted the most comprehensive screening to date, testing 288 pesticides on dopaminergic neurons derived from Parkinson’s patients using induced pluripotent stem cell technology. They identified 10 pesticides that were directly toxic to these neurons and 53 pesticides implicated in Parkinson’s overall. The troubling finding was that most of these chemicals had not been previously studied for neurological effects and many are still in active use. This means the regulatory system has been approving and renewing pesticides without adequate testing for the type of slow, cumulative brain damage that leads to Parkinson’s decades later. The list of concerning chemicals extends beyond the obvious culprits. Organophosphate pesticides, the largest group of insecticides used in the United States, inhibit acetylcholinesterase, disrupt mitochondrial function, and cause oxidative stress. All three of these pathways are linked to neurodegeneration.
A July 2025 study published in npj Parkinson’s Disease found that rotenone triggers lasting alterations in brain gene activity and epigenetic markers, especially in the substantia nigra, the brain region most devastated by Parkinson’s. Genes related to inflammation and immune activation were turned on while protective genes were shut down, and these changes persisted long after exposure ended. However, if you are thinking that avoiding a handful of well-known pesticides solves the problem, the reality is more complicated. Glyphosate, the active ingredient in Roundup and the most widely used herbicide in the world, has also come under scrutiny. A commentary in The Lancet Planetary Health in November 2023 argued that current pesticide regulations are inadequate for protecting brain health, citing a biologically plausible link between glyphosate and nigrostriatal cell death. The international SPRINT study found glyphosate residues in the feces of 70 percent of participants, including not just farmers but their neighbors and urban residents with no direct agricultural contact. The sheer ubiquity of exposure means that dietary choices represent one of the few variables individuals can actually control.
The 2025 Dirty Dozen and What It Means for Neurological Health
The Environmental Working Group’s 2025 Dirty Dozen list represents a significant update from previous years because the methodology was revised to factor in pesticide toxicity, not just the presence or amount of chemical residues. Based on analysis of more than 53,000 USDA samples of 47 fruits and vegetables, the 2025 list ranks green beans first, followed by spinach, bell and hot peppers, kale and related greens, strawberries, grapes, nectarines, pears, peaches, blackberries, cherries, and potatoes. Blackberries and potatoes are new additions to the list this year. The numbers behind these rankings are stark. More than 95 percent of conventionally grown Dirty Dozen samples contained pesticide residues. Across all Dirty Dozen items, 203 different pesticides were detected. Some individual samples contained more than 50 different pesticides.
Peaches alone showed residues of 59 different pesticides. Among the chemicals detected was permethrin, a neurotoxic insecticide that has been banned in Europe since 2000 but remains legal in the United States. For someone trying to reduce neurological risk, these are not abstract numbers. Each of these chemicals interacts with brain tissue in ways that may be individually minor but cumulatively significant, particularly given the dose-response relationship demonstrated in organophosphate research. A practical example illustrates the stakes. A person who eats conventional strawberries on their morning cereal, a spinach salad at lunch, and bell peppers in a stir-fry at dinner has consumed three Dirty Dozen items in a single day, potentially exposing themselves to dozens of distinct pesticide compounds. Switching just these three items to organic eliminates a meaningful portion of daily pesticide intake without requiring a complete overhaul of shopping habits.
Where to Save Money with the Clean Fifteen
Not all produce carries the same pesticide burden, and buying everything organic is neither necessary nor financially realistic for most families. The EWG’s 2025 Clean Fifteen list identifies produce items where conventional versions carry minimal risk. Nearly 60 percent of Clean Fifteen samples had no detectable pesticide residues at all. The top items include avocados, papayas, pineapples, onions, and sweet corn. Bananas were also highlighted for low overall pesticide toxicity.
The tradeoff is straightforward. Spend your organic budget on the items that matter most, the Dirty Dozen, and buy conventional versions of Clean Fifteen produce without guilt. An avocado’s thick skin means that even if pesticides are applied during growing, almost none reaches the flesh you eat. The same principle applies to pineapples, onions, and sweet corn. If your grocery budget is tight, prioritizing organic versions of spinach, strawberries, and bell peppers while buying conventional avocados and pineapples gives you the greatest neurological protection per dollar spent. A family that switches just the top six Dirty Dozen items to organic can significantly reduce pesticide exposure while adding only a modest amount to their weekly grocery bill.
Genetic Vulnerability and Who Should Be Most Concerned
Not everyone faces equal risk from pesticide exposure, and this is an important caveat. An April 2024 UCLA study of nearly 800 Central Valley residents with Parkinson’s disease found that certain genetic variants could explain how long-term pesticide exposure increases Parkinson’s risk. People with these variants who were also exposed to 10 pesticides commonly used on cotton crops were at particularly elevated risk. This means that for some individuals, dietary pesticide exposure may be especially dangerous, while others may have greater natural resilience. The challenge is that most people do not know their genetic risk profile for pesticide sensitivity. Genetic testing for Parkinson’s susceptibility is still in its early stages and not widely available.
In the absence of personalized risk information, the precautionary approach makes sense for everyone, but it is especially important for people with a family history of Parkinson’s or other neurodegenerative diseases. A 2025 JAMA study found that people living just one to three miles from golf courses, which are heavily treated with pesticides, had elevated Parkinson’s risk. If proximity to pesticide application increases risk, dietary exposure likely does as well, particularly for those with underlying genetic susceptibility. One limitation worth noting: most of the large epidemiological studies focus on occupational or residential exposure to pesticides, not dietary exposure specifically. The pesticide levels on produce are lower than what a farmworker encounters. However, dietary exposure is chronic and lifelong, and the cumulative effect of consuming small amounts of dozens of different pesticides daily for decades has never been adequately studied. The absence of evidence is not evidence of absence, and the biological mechanisms through which these chemicals damage neurons are well established regardless of the route of exposure.
Pesticides and Developing Brains in Children
The neurological risks of dietary pesticide exposure extend beyond Parkinson’s, and families with young children have additional reasons to prioritize organic produce. Neurotoxic pesticides like organophosphates cross the placenta and the fetal blood-brain barrier, and research has linked prenatal exposure to lower IQ, attention deficits, and learning disabilities in children. Chlorpyrifos exposure during pregnancy and early childhood has been specifically linked to lower birth weight and slower motor development.
For families on a budget, the priority should be organic versions of the foods children eat most frequently. If your toddler eats strawberries and grapes daily, those are the items to buy organic first. The developing brain is far more vulnerable to chemical disruption than the adult brain, and the effects of early exposure may not become apparent until years or decades later.
Where Pesticide Regulation Is Heading
The gap between scientific evidence and regulatory action remains wide, but it is narrowing. The fact that permethrin has been banned in Europe since 2000 while still appearing on American produce illustrates how far behind US pesticide regulation has lagged. The Lancet Planetary Health commentary’s assertion that current regulations are inadequate for protecting brain health reflects a growing consensus in the research community.
The UCLA and Harvard screening of 288 pesticides revealed that most of the chemicals found to be toxic to dopaminergic neurons had never been previously studied for this effect, meaning the regulatory approval process has systematically failed to test for the type of harm that matters most. Looking ahead, the shift in the EWG’s methodology to factor in toxicity rather than just presence marks an important change in how consumers can evaluate risk. As more research connects specific pesticides to specific neurological damage pathways, we can expect more targeted guidance about which chemical-crop combinations pose the greatest threat. In the meantime, the precautionary principle applies: where affordable and available, choosing organic versions of high-pesticide produce is one of the most accessible steps anyone can take to reduce their neurological risk.
Conclusion
The research connecting pesticides to Parkinson’s disease has moved well beyond correlation. Studies from UCLA, Harvard, and large-scale agricultural health investigations have identified specific chemicals, specific biological mechanisms, and specific dose-response relationships. Chlorpyrifos, rotenone, paraquat, and at least 10 other pesticides have been shown to directly damage or destroy the dopamine-producing neurons whose loss causes Parkinson’s. These chemicals appear on conventional produce at measurable levels, and the 2025 Dirty Dozen list, now weighted for toxicity, provides a practical guide for reducing exposure.
You do not need to buy everything organic to meaningfully reduce your risk. Focus your organic purchases on green beans, spinach, bell peppers, kale, strawberries, and grapes, the items that carry the highest toxic pesticide loads. Buy conventional avocados, pineapples, onions, and sweet corn without concern. Wash all produce thoroughly, though washing removes only surface residues and not systemic pesticides absorbed into the plant tissue. For families with a history of Parkinson’s or other neurodegenerative conditions, and for households with young children, prioritizing organic produce is not a luxury but a reasonable, evidence-based precaution.
Frequently Asked Questions
Does washing produce remove pesticides?
Washing removes some surface pesticide residues but not all. Systemic pesticides, which are absorbed into the plant’s tissue during growth, cannot be washed off. Peeling can help for items like apples and pears, but you lose valuable fiber and nutrients in the skin. Washing is still worth doing, but it is not a substitute for buying organic when it comes to the most contaminated items.
Is frozen organic produce as good as fresh organic?
Yes. Frozen organic fruits and vegetables are often more affordable than fresh organic and retain their nutritional value. They are also subject to the same organic certification standards. Frozen organic spinach or strawberries can be a cost-effective way to avoid pesticide exposure on two of the highest-risk Dirty Dozen items.
Are “no-spray” or “pesticide-free” labels the same as organic?
Not necessarily. Only the USDA Organic certification guarantees that synthetic pesticides were not used. Labels like “no-spray” or “pesticide-free” are not federally regulated and can mean different things depending on the farm. If you are buying from a local farmer’s market, ask the grower directly about their practices, but for grocery store purchases, look for the USDA Organic seal.
Does organic farming use any pesticides at all?
Organic farming does permit certain naturally derived pesticides, such as copper sulfate and neem oil. However, these are generally less toxic to human neurons than the synthetic organophosphates, pyrethroids, and herbicides used in conventional agriculture. The key difference for neurological health is the absence of the specific chemicals, like chlorpyrifos and permethrin, that research has linked to dopaminergic neuron damage.
How much does switching to organic for the Dirty Dozen cost?
The cost varies by region and season, but studies suggest that buying organic versions of only the Dirty Dozen items adds roughly 20 to 30 percent to the cost of those specific items. Since the Dirty Dozen represents a fraction of total grocery spending, the overall budget impact is typically modest. Buying frozen organic, shopping sales, and using store-brand organic options can reduce the premium further.
