Pesticides and Your Health: Understanding Risks and Practical Ways to Protect Yourself

Disclaimer: This article has been revised to incorporate recent scientific developments, including ongoing controversies and practical, inclusive consumer strategies. Pesticide risks are dose-dependent, and eating fruits/vegetables remains essential for health.

Pesticides are substances designed to control pests, with nearly 11,000 products approved by the EPA for use in everything from agriculture to personal care.^[1-4] While these chemicals protect crops by poisoning target organisms,^[25]  their widespread use has significantly impacted biodiversity, often stripping ecosystems of beneficial wildlife.

“Recent reporting warns that our pest‑control success has come at a steep ecological cost: in some Iowa cornfields, only cornstalks remain—no bees, no insects, nothing else.^[5-7,40] Other analyses show that widely used pesticides are driving steep declines in U.S. bird populations, accelerating a biodiversity loss that has been unfolding for more than fifty years.^[49]”

For humans, exposure ranges from low-level risks to high toxicity. Although USDA monitoring shows that most produce falls within safety limits, gaps remain due to inconsistent sampling and environmental variables. Understanding these vulnerabilities is the first step toward reducing personal exposure and protecting your health.

Potential Risks of Pesticides

Speaking the least, pesticides can irritate the skin, eyes, nose, or mouth. In addition, exposure to them may result in the following:^{[1, 8-15]}

• Reproductive effects: Can impair fertility or reduce the ability to produce healthy offspring.
• Teratogenic effects: May harm fetal development, including increased risk of birth defects.
• Carcinogenic effects: Some pesticides are linked to higher cancer rates, especially among farm workers (e.g., stomach, brain, prostate, lymphatic and blood cancers).
• Oncogenic effects: Can promote tumor growth, even when tumors are not cancerous.
• Mutagenic effects: May cause permanent, inheritable changes to DNA.
• Neurotoxicity: Can damage the nervous system; high exposures have been associated with developmental issues such as ADHD.^[45]
• Immunosuppression: May weaken immune defenses, reducing the body’s ability to fight infections.

Some pesticides—such as organophosphates—are linked to neurotoxicity, endocrine disruption, and certain cancers, though the evidence is largely correlational, higher for occupational exposure and dose‑dependent. This toxicity extends to the environment; for instance, recent research on 19 common pesticides demonstrated varying levels of cytotoxicity in rainbow trout, specifically damaging gill, liver, and intestinal cell lines.^[54] While dietary exposure for most people remains low under EPA standards, vulnerable groups and sensitive ecosystems should take extra care.

DNA Methylation^[16-23]

Growing research continues to show that pesticide exposure is linked to a range of serious health effects, even though many mechanisms are still being clarified. One emerging pathway is epigenetic disruption—particularly changes in DNA methylation^[21,47]—that can alter how genes function without changing the underlying DNA sequence.

Although pesticides undergo carcinogenicity testing before approval, epidemiological studies have repeatedly associated exposure with elevated cancer risks. This pattern suggests that some pesticides may promote cancer through non‑mutagenic routes. Recent studies support this idea, showing that pesticide‑induced carcinogenesis may be driven in part by epigenetic mechanisms.

Epigenetics refers to heritable changes in gene activity that do not involve alterations to the DNA sequence.^[16,44,47]  Processes such as DNA methylation and histone modification can switch genes on or off, influencing disease risk across the lifespan.

Northwestern University researchers examined seven widely used pesticides—fonofos, parathion, terbufos, chlorpyrifos, diazinon, malathion, and phorate—and found that they can modify gene‑promoter DNA methylation in vitro, reinforcing the role of epigenetic disruption in pesticide‑related cancers.^[21] More recent reviews (2023–2025) extend these concerns, linking pesticide‑driven epigenetic changes to metabolic disorders, reproductive dysfunction, and developmental effects.^[55-58]

Chlorpyrifos has faced escalating global restrictions: the EU banned it in 2020, the U.S. now limits it to 11 ‘critical’ crops despite legal reversals, and many states maintain full bans.^[59] In 2025, the Stockholm Convention moved to eliminate it worldwide due to its persistence and neurodevelopmental harm.

Video 1. How to reduce toxic chemicals in your household dust (YouTube link)

Who Are the Most Vulnerable?

How to Reduce Exposure to Pesticides?

Pesticide risk is simple: RISK = TOXICITY × EXPOSURE.  

Since toxicity is fixed, the only way to lower risk is to reduce exposure—mainly from food and environmental sources.

1. Reduce Exposure From Foods

• Use EWG’s Shopper’s Guide to identify the Dirty Dozen (buy organic) and the Clean Fifteen (safe to buy conventional—nearly 60% have no detectable residues in 2025 data).
• Wash produces under running water for 15–30 seconds, rubbing gently.^[36]
• Peel and trim when possible: peel carrots/apples/potatoes, discard outer leaves of greens, trim fat/skin from meats where residues can accumulate.
• Cook foods when appropriate—boiling and frying reduce many residues.
• Eat a variety of fruits and vegetables to avoid repeated exposure to the same pesticide.
• Choose affordable alternatives: frozen or canned produce, farmers’ markets, or grow simple items at home (herbs, greens, onions).

2. Reduce Exposure from Your Environment

• Outdoor pesticides migrate indoors. EPA studies show residues tracked in on shoes and pets can raise pesticide levels in carpet dust up to 400×.^[37] 
• Indoor dust often contains more pesticide residue than outdoor soil, even on farms.^[33]
• Once inside—away from sunlight and rain—pesticides can persist for years.
• Reduce indoor contamination by removing shoes, cleaning floors regularly, and limiting home use of insecticides and lawn chemicals.

References

1. Toxicity of Pesticides (Cornell University)
2. Superficial Safeguards: Most Pesticides Are Approved by Flawed EPA Process (Natural Resources Defense Council)
3. Pesticide Reregistration Status (EPA)
4. A Loophole For Pesticides Puts Public’s Health At Risk (EWG)
5. Cornstalks Everywhere But Nothing Else, Not Even A Bee (NPR)
6. Pesticide toxicity to bees (Wikipedia)
7. Pesticides Applied to Crops and Honey Bee Toxicity
• Relative to other insect genomes, the honey bee genome is markedly deficient in the number of genes encoding detoxifica­tion enzymes.
• Bee colony numbers have declined by 45% over the past 60 years.
8. Pesticides and Cancer (Cancer Research UK)
9. Pesticide Exposure May Contribute to ADHD (American Academy of Pediatrics)
10. Pesticides on Oncology.com
11. Banned Pesticide DDT Is Still Killing California Condors
12. Pesticides used in South American GMO-based agriculture: A review of their effects on humans and animal models
13. Birth defects caused by glyphosate, Andres Carrasco (Talked at UC Irvine)
14. Glyphosate-Based Herbicides Produce Teratogenic Effects on Vertebrates by Impairing Retinoic Acid Signaling
• The direct effect of glyphosate on early mechanisms of morphogenesis in vertebrate embryos opens concerns about the clinical findings from human offspring in populations exposed to GBH in agricultural fields.
15. Pesticides and Food: Health Problems Pesticides May Pose (EPA)
16. Epigenetics (Wikipedia)
17. Methylation subtypes and large-scale epigenetic alterations in gastric cancer
• Cancer-specific epigenetic alterations were observed in 44% of CpGs, comprising both tumor hyper- and hypomethylation.
• Our results provide insights into the epigenetic impact of environmental and biological agents on gastric epithelial cells, which may contribute to cancer.
18. Jones PA, Laird PW: Cancer epigenetics comes of age. Nat Genet 21:163-167, 1999
19. Jones PA: The DNA methylation paradox. Trends Genet 15:34-37, 1999
20. Epigenetic analysis of stomach cancer finds new disease subtypes (Duke-NUS Graduate Medical School)
• Many of the methylation alterations were associated with significant changes in gene expression, suggesting that the methylation alterations may be functionally important in the development of gastic cancer.
21. DNA methylation alterations in response to pesticide exposure in vitro
• The present study provides evidence to support the hypothesis that pesticide-induced cancer may be mediated in part by epigenetic mechanisms.
22. DNA Methylation and Cancer (Journal of Clinical Oncology)
23. Singal R, Wang SZ, Sargent T, et al: Methylation of promoter proximal-transcribed sequences of an embryonic globin gene inhibits transcription in primary erythroid cells and promotes formation of a cell type-specific methyl cytosine binding complex. J Biol Chem 277: 1897-1905, 2002
24. Nation's Pediatricians Warn Against Pesticides in Food (EWG)
25. Pesticide (Wikipedia)
26. Systemic Pesticides: Chemicals You Can’t Wash Off
27. Arsenic in Rice (FDA)
28. 滅芬諾 (Methoxyfenozide) 農藥 found in red wine (News; in Chinese)
29. You cannot wash off systemic pesticides
30. AAP Makes Recommendations to Reduce Children's Exposure to Pesticides (American Academy of Pediatrics)
31. Nation's Pediatricians Warn Against Pesticides in Food (EWG)
32. Sustaining the Earth by G. T. Miller
33. R. Lewis et al., "Measuring and Reducing Exposure to the Pollutants in House Dust," American Journal of Public Health 85 (1995): 1168.
34. Pesticide Action Network--Advancing alternatives to pesticides worldwide
35. The Healthy Home by Dave Wentz and Dr. Myron Wentz
36. Four Important Cleaning Tasks In Your Morning Routine (Travel to Health)
37. R. Renner, "Curse This House," New Scientist, iss. 2289, May 5, 2001.
38. 蔬果上残余农药 如何影响我们的健康 (in Chinese)
39. Pesticides (Diabetes and the Environment)
40. The Year the Monarch Didn’t Appear
• A major cause is farming with Roundup, a herbicide that kills virtually all plants except crops that are genetically modified to survive it.
41. Black Raspberries Protectively Regulate Methylation of Wnt Pathway Genes in Precancerous Colon Tissue
• Black raspberries inhibit colonic ulceration and, ultimately, colon cancer partly through inhibiting aberrant epigenetic events that dysregulate Wnt signaling.
42. The Hidden Truth About Peanuts: From Food Allergies to Farm Practices
• It is common to see a conventional peanut crop sprayed with some type of pesticide every 8-10 days during the growing season.
• Most of the peanuts consumed in the U.S. are now one of the most pesticide-contaminated snacks we eat.
43. Toxic pesticides from GM food crops found in unborn babies
• The research suggested the chemicals were entering the body through eating meat, milk and eggs from farm livestock which have been fed GM corn.
44. Team reprograms social behavior in carpenter ants using epigenetic drugs
• Epigenetic regulation has been observed to affect a variety of distinct traits in animals, including body size, aging, and behavior.
45. Attention-Deficit/Hyperactivity Disorder and Urinary Metabolites of Organophosphate Pesticides
• Scientists' findings support the hypothesis that organophosphate exposure, at levels common among US children, may contribute to ADHD prevalence. 
46. Outside Variants Wired into Epigenetic Circuits That Can Boost Disease Risk
47. Unexpected role for epigenetic enzymes in cancer
48. Which Food Fights Cancer Better?  (Travel to Health)
49. Alarm as pesticides spur rapid decline of US bird species
• Popular pesticides are causing bird species to decline at an alarming rate in the US, adding fuel to a 50-year downward trend in bird biodiversity, a new report has found.
50. Major international study reports the impact of genetics on epigenetic factors
51. Genetic Engineering of Major Crops: the Most Recent Depressing Episode
• There’s no way you can blast that much weed killer on GE crops without causing resistance and superweeds, which means even more toxic herbicides would eventually be needed. That of course was the exact business plan of the pesticide industry.
52. Can biological ageing be slowed, and can epigenetic clocks measure it? By Liam Drew (pdf)
53. A Six Months Exercise Intervention Influences the Genome-wide DNA Methylation Pattern in Human Adipose Tissue
• Exercise induces genome-wide changes in DNA methylation in human adipose tissue, potentially affecting adipocyte metabolism.
54. Cytotoxicity of 19 pesticides in rainbow trout gill, liver, and intestinal cell lines
55. Dietary Risk Index (DRI): A system used by Heartland Health Research Alliance (HHRA), combining testing data with toxicity thresholds to track chronic dietary risks across foods and over time. 
56. Pesticides — FDA
57. Pesticide Data Program (PDP)—USDA
58. Health Risks of Pesticides in Food (University of Washington)
59. Can chlorpyrifos be used in the 2025 growing season?