Lawns, pesticides, and long-term health conditions

A few weeks ago, Julija¹ (our in-house scientist and DPhil/PhD) hit me with a shocking fact:

This absolutely terrified me. I live within a mile of not one, not two, but three golf courses.

After a minor panic (and a frantic Zillow search), I dove into research mode.

Turns out it’s not golf balls causing brain-damage (though 2-3 Americans die per year thanks to wayward golf balls² ), rather it’s those lush, chemically-treated greens.

And the same goes for sports fields, some parks and even home lawns (and you bet I live near all of those, too 🥴).

So, short of moving house to a grass-free suburb, how do you avoid exposure to these neurotoxic chemicals?

How golf-courses (and other grassy spaces) jeopardize your brain health.

New research published in JAMA³ highlights a huge health risk for those living nearby pristine and green golf-courses:

• Live within 1 mile? Your risk of developing Parkinson’s disease increases by 126%.

• Even 1–3 miles away, your risk rises between 92%–198%.

• Using well water near a golf course? Your Parkinson’s risk almost doubles.

Even when the researchers adjusted for other factors, the link stayed strong.

The culprit? Most likely pesticide use.

Pesticide use on U.S. golf-courses are 15X higher than used in Europe. And even higher than the amount of pesticides used on farms*.

*Obviously pesticide usage on farms is incredibly harmful because we’re directly eating the food grown there. But we’ll save that problem for it’s own edition of the Superpower Journal!

Golf courses typically use a toxic cocktail of herbicides (weed-killers), fungicides (mold-killers) and insecticides (bug-killers), which spread through the air and seeps into groundwater.

While the JAMA study doesn’t say pesticides directly cause Parkinson’s, the research consistently shows that more exposure = higher risk.

Pesticides may harm your brain through:

• Oxidative stress: Chemicals like glyphosate (a widely used herbicide) trigger harmful free radicals that damage vital dopamine-producing neurons⁴, which are essential for movement⁵.

• Inflammation: Pesticides cause ongoing, low-level inflammation⁶⁷, gradually killing these neurons.

• Protein misfolding: Pesticides encourage healthy proteins to misfold and clump into harmful deposits, a hallmark of Parkinson’s⁸.

Why do household herbicides use these chemicals?

Glyphosate, used widely in domestic and commercial herbicides, kills plants by blocking EPSP synthase (an enzyme essential for producing amino acids) causing the plants to starve and die.

Humans and animals don't rely on this enzyme, which is why glyphosate was initially thought safe. However, new research is questioning that assumption, particularly because it might harm our microbiome⁹ and cause other unintended consequences.

It’s not just golf-courses. Green spaces are also problematic.

This makes me furious.

I’m a mom. Every day, I get my baby outside: lawns, playgrounds, soccer fields. Fresh air, green grass. Good parenting, right?

Turns out those same fields are sprayed with pesticides.

Much like golf-courses, sport-fields and private lawns use concerning amounts of pesticides.

And guess who is most vulnerable to these pesticides?

The people who use these green spaces the most - our kids.

Pesticide risks and our kids.

Why are kids particularly at risk?

Anyone with a baby or toddler knows the drill: crawling on grass, hands in mouth, no filter. That’s direct exposure to whatever’s been sprayed on the lawn.

And kids aren’t just mini adults, their brains, immune systems, and organs are still developing, making them more vulnerable.

Plus, they’ve got decades ahead of them, giving more time for cumulative effects to manifest and problems to stack up.

Exposure to lawn and agricultural pesticides has been linked to increased risks of:

• Childhood Leukemia and pediatric cancers. Early exposure to pesticides increases rates of childhood leukemia and lymphoma¹⁰ , brain tumors and neuroblastoma- a cancer affecting nerve tissues, particularly when exposure occurs prenatally¹¹ .

• Chronic health conditions. 480 children were tracked from birth to age 18. The findings? Higher levels of glyphosate in children's urine were linked to signs of liver inflammation and early metabolic issues later as young adults.¹² .

• Developmental delays. Kids exposed to chlorpyrifos (a pesticide used for ants, termites, and mosquitos) in the womb has been associated with structural changes in the brain and a 5.3 point reduction in IQ¹³ . This might not sound like much, but a 5.3 drop in IQ is both statistically solid and clinically serious.

• Respiratory issues. A 2024 meta-analysis¹⁴ involving over 118,000 children found that pesticide exposure was associated with a 24% increased risk of asthma, 34% higher risk of wheezing, and a 79% higher risk of lower respiratory tract infections.

• Endocrine disruption. Herbicides like 2,4-D has shown hormonal disruption in animal studies, particularly affecting thyroid and reproductive hormones¹⁵¹⁶ .

And risk isn't just about direct exposure after your kids are born, it starts even earlier.

In an old but powerful study¹⁷ , mothers who used flea and tick pesticides during pregnancy had kids with a 70% higher risk of developing brain tumors. That risk doubled for moms who personally handled these products.

Pets: The early warning system in your backyard.

Don’t have kids, but have a fur-baby? You still might want to rethink what's sprayed on your lawn.

Dogs and cats roll in the grass, lick their paws, and breathe right at ground level (just like toddlers). That puts them in prime position for pesticide exposure.

One study¹⁸ found that dogs in homes using lawn herbicides had a 3.6X higher risk of bladder cancer. If insecticides were also used, that jumped to 7.2X.

Because pets have shorter lifespans they tend to show symptoms sooner, this sadly makes them the perfect early-warning system for toxic pesticide exposure in and around the home.

If your dog’s absorbing these chemicals, chances are, so are you.

So what can we do about this?

The JAMA Parkinson’s findings are alarming… but here's the good news: this is a problem you can actively do something about, and minimize your exposure.

Test your local or home environment.

• Soil and water testing: Test your water, yard, local park or garden for pesticide residues, especially if you live near golf courses or farms. Local universities often have great programs and resources for soil testing¹⁹ (check out Michigan State as an example²⁰ ).

  • Scope our Superpower Journal on water if you want to dive into water safety a bit more.

• Air quality: Pesticides drift, especially on windy days²¹ . Keep windows shut when spraying is happening nearby, and consider using a HEPA air filter - they cut indoor pesticide particles by nearly 40%²² .

  • Reply to this email if you want to know how to rig up a HEPA filter for mega cheap using just a standard fan, some cable and a filter replacement.

Monitor your local parks, golf-courses and lawns.

• Watch for signs: Keep your eyes peeled for posted warnings like "Stay off until dry." Better yet, wait at least 24–48 hours before re-entering treated areas.

• Ask questions: If your neighbor’s lawn service, local golf course, or city council sprays grass, ask what chemicals they're using, and when. Knowing their schedule helps you avoid exposure, plan accordingly and advocate for safer lawn care.

Embrace healthy lawn alternatives.

• Natural landscaping: Plant native grasses and low-maintenance ground covers that need minimal chemical input²³ . Encourage neighbors to do the same.

  • Consider ditching the ‘clean, green’ lawn look. Manicured, empty lawns originated as a status-symbol for the wealthy. And we all know nowadays that health is wealth, instead!

• Embrace biodiversity: Allow some variety, like clover, to naturally maintain lawn health without pesticides²⁴ .

Daily habits to reduce exposure.

• Shoes off at the door: Prevent pesticides from tracking indoors. Also keeps your house cleaner, so win-win! Contaminated soil or dust is a major route by which pesticides get indoors²⁵ .

• Wash hands and gear: Always wash up after outdoor play or gardening, and wash clothes that have touched treated grass.

• Clean pets and kids: Wipe down paws and fur after outdoor activities to keep residues out of your home. If playing outside with kids, always wash hands before eating.

• Choose clean food: Buy organic produce or wash thoroughly to lower overall pesticide intake. 🍎We’ll deep-dive on pesticides on food soon🍎

Community and policy actions.

• Push for bans and limits: Advocate for local laws restricting cosmetic pesticide use, Integrated Pest Management (IPM)²⁵ and pesticide-free parks and schools. Individual actions are good, but community-wide bans on unnecessary lawn pesticides can slash chemical runoff by over 80% and significantly reduce cancers and neurological diseases- just ask Ontario²⁶ .

Living next door to a golf course doesn’t mean you’re doomed to Parkinson’s (or anything else for that matter). But knowledge is power, and simple choices can drastically lower your exposure to harmful pesticides.

So know your surroundings, keep an eye on local practices, and spread the word.

Your lawn might lose a bit of its perfect, lush green- but your brain will thank you.

Reviewed by Julija Rabcuka, BA (Oxon), MSc, PhD (ABD), University of Oxford.

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