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Exposure to Pesticides, Herbicides, & Insecticides: Human Health Effects

Gardening supplies set up in a garden, showing that toxic pesticide exposure may lead to adverse health effects.

Learn proven functional medicine strategies for treating toxic exposures at the upcoming Environmental Health Advanced Practice Module. SEE FULL PROGRAM DETAILS 


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Pesticides and a wide variety of other chemicals persist in the environment and make their way into our everyday lives. Researchers have learned a great deal in recent years about how these toxicants affect the human population, where they originate, and how to improve our ability to detoxify in a toxic world. How can clinicians help patients manage the health risks of exposure to these ubiquitous substances?

Pesticides

Pesticide use is steadily increasing worldwide. Estimates suggest that global pesticide use grew 20% over the last decade and by 153% in low-income countries, specifically.1 Organophosphate pesticides are one of the most extensively applied insecticides in the field of agriculture.2 Approximately 40% of all pesticides produced and used commercially belong to this category.2 Pesticides have been associated with short- and long-term effects on human health, including elevated cancer risks3 and potential disruption of the body’s metabolic functioning4 as well as the reproductive, immune, and nervous systems.5-7 A 2022 systematic review and meta-analysis suggests that pesticide exposure is a major risk factor for metabolic syndrome.4 The analysis included 12 studies for a total of 6,789 participants, in which 1,981 (29.1%) had metabolic syndrome; overall exposure to pesticides and their contaminants increased the risk of metabolic syndrome by 30%.

Exposure to pesticides predominantly comes from dermal absorption or through ingestion,2 particularly through food—either on or within fruits and vegetables or in the tissues of fish and other animals we eat—through contaminated drinking water, or in the air we breathe.8 Respiratory pathologies may be related to occupational exposure to pesticides, including asthma, chronic obstructive pulmonary disease (COPD), and lung cancer.9

Insecticides & Herbicides

Neonicotinoid pesticides are a class of chemicals used as insecticides in agricultural settings and to target ticks and fleas on domestic pets. They have been detected in water, soil, dust, various crops, birds, and humans.10 Exposure routes for humans may include dietary and water intake as well as dust and pollen inhalation, and recent research indicates neonicotinoids and their metabolites may have adverse health effects such as oxidative stress, neurological symptoms, osteoporosis, and cancer.10

Organophosphates (carbon- and phosphate-containing molecules) are commonly used components of insecticides and herbicides in the US in all market sectors (i.e., agriculture, home and garden, industrial, commercial, and government).11 Increased cancer risk has been associated with several organophosphate insecticides in epidemiological studies in the US, Canada, and Italy.11,12 In addition to cancer, studies suggest that organophosphates may be tied to a wide variety of other negative health effects, including ADHD,11 muscle weakness, and numbness.12

Glysophate

Use of the herbicide glyphosate began in the 1970s, and the chemical swiftly attained widespread use in modern agriculture, becoming the most commercially successful and widely used herbicide of all time as of 2016.13 Levels of glyphosate and its primary metabolite have been detected in the air, soil, water, and food.14

A formal review of glyphosate by the Department of Health and Human Services and the Agency for Toxic Substances and Disease Registry was published in 2020, finding some statistically significant links to some cancers like non-Hodgkin’s lymphoma.15 In addition, studies suggest that glyphosate may be associated with increased breast cancer risk.16,17 In 2020, Bayer, the company behind Roundup weed killer, which contains glyphosate, settled most of the current and possible future lawsuits brought against it by plaintiffs alleging that glyphosate causes cancer.18 However, glyphosate continues to be used around the world, and the US Environmental Protection Agency continues to indicate that glyphosate products pose no risks of concern to human health when used according to label directions.19

Clinical Considerations

A large part of reducing a patient’s total toxic burden is through education—bringing the patient into a level of awareness regarding different sources of toxicants so they can avoid potential exposures. From here, many functional medicine strategies for detoxification have a nutritional focus to support the body’s natural processes for mobilization, biotransformation, and elimination of toxic compounds.

Optimizing a patient’s nutritional status, ensuring adequate fiber and water intake, eating more phytonutrient-dense and diverse foods, and supporting liver function through targeted, nutrient-dense diets are all treatment approaches within the functional medicine model that may be part of a patient’s personalized therapeutic strategy.

At IFM’s Environmental Health Advanced Practice Module (APM), learn more about how your patients’
physical environment and toxicant exposure levels may impact their health outcomes and what lifestyle-based
tools may benefit their wellness path.

Learn More About Biotransformation Pathways and Toxic Exposures

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References

  1. Shattuck A, Werner M, Mempel F, et al. Global pesticide use and trade database (GloPUT): new estimates show pesticide use trends in low-income countries substantially underestimated. Glob Environ Change. 2023;81:102693. doi:1016/j.gloenvcha.2023.102693
  2. Kaushal J, Khatri M, Arya SK. A treatise on organophosphate pesticide pollution: current strategies and advancements in their environmental degradation and elimination. Ecotoxicol Environ Saf. 2021;207:111483. doi:1016/j.ecoenv.2020.111483
  3. Matich EK, Laryea JA, Seely KA, Stahr S, Su LJ, Hsu PC. Association between pesticide exposure and colorectal cancer risk and incidence: a systematic review. Ecotoxicol Environ Saf. 2021;219:112327. doi:1016/j.ecoenv.2021.112327
  4. Lamat H, Sauvant-Rochat MP, Tauveron I, et al. Metabolic syndrome and pesticides: a systematic review and meta-analysis. Environ Pollut. 2022;305:119288. doi:1016/j.envpol.2022.119288
  5. Sturm ET, Castro C, Mendez-Colmenares A, et al. Risk factors for brain health in agricultural work: a systematic review. Int J Environ Res Public Health. 2022;19(6):3373. doi:3390/ijerph19063373
  6. Fucic A, Duca RC, Galea KS, et al. Reproductive health risks associated with occupational and environmental exposure to pesticides. Int J Environ Res Public Health. 2021;18(12):6576. doi:3390/ijerph18126576
  7. Tan J, Ma M, Shen X, Xia Y, Qin W. Potential lethality of organochlorine pesticides: inducing fatality through inflammatory responses in the organism. Ecotoxicol Environ Saf. 2024;279:116508. doi:1016/j.ecoenv.2024.116508
  8. Boonupara T, Udomkun P, Khan E, Kajitvichyanukul P. Airborne pesticides from agricultural practices: a critical review of pathways, influencing factors, and human health implications. Toxics. 2023;11(10):858. doi:3390/toxics11100858
  9. Tarmure S, Alexescu TG, Orasan O, et al. Influence of pesticides on respiratory pathology – a literature review. Ann Agric Environ Med. 2020;27(2):194-200. doi:26444/aaem/121899
  10.  Zhang D, Lu S. Human exposure to neonicotinoids and the associated health risks: a review. Environ Int. 2022;163:107201. doi:1016/j.envint.2022.107201
  11.  Lerro CC, Koutros S, Andreotti G, et al. Organophosphate insecticide use and cancer incidence among spouses of pesticide applicators in the Agricultural Health Study. Occup Environ Med. 2015;72(10):736-744. doi:1136/oemed-2014-102798
  12.  Bastos PL, Bastos AFTL, Gurgel ADM, Gurgel IGD. Carcinogenicity and mutagenicity of malathion and its two analogues: a systematic review. Carcinogenicidade e mutagenicidade do malathion e seus dois análogos: uma revisão sistemática. Cien Saude Colet. 2020;25(8):3273-3298. doi:1590/1413-81232020258.10672018
  13.  Hongsibsong S, Sittitoon N, Sapbamrer R. Association of health symptoms with low-level exposure to organophosphates, DNA damage, AChE activity, and occupational knowledge and practice among rice, corn, and double-crop farmers. J Occup Health. 2017;59(2):165-176. doi:1539/joh.16-0107-OA
  14.  Soares D, Silva L, Duarte S, Pena A, Pereira A. Glyphosate use, toxicity and occurrence in food. Foods. 2021;10(11):2785. doi:3390/foods10112785
  15.  Agency for Toxic Substances and Disease Registry. Toxicological Profile for Glyphosate. US Department of Health and Human Services; 2020. Accessed June 24, 2024. https://www.atsdr.cdc.gov/toxprofiles/tp214.pdf
  16.  Franke AA, Li X, Shvetsov YB, Lai JF. Pilot study on the urinary excretion of the glyphosate metabolite aminomethylphosphonic acid and breast cancer risk: the Multiethnic Cohort study. Environ Pollut. 2021;277:116848. doi:1016/j.envpol.2021.116848
  17.  Sritana N, Suriyo T, Kanitwithayanun J, Songvasin BH, Thiantanawat A, Satayavivad J. Glyphosate induces growth of estrogen receptor alpha positive cholangiocarcinoma cells via non-genomic estrogen receptor/ERK1/2 signaling pathway. Food Chem Toxicol. 2018;118:595-607. doi:1016/j.fct.2018.06.014
  18.  Yan H. Bayer settles lawsuits from cancer patients over Roundup weed killer in $10 billion agreement. CNN Health. Published June 24, 2020. Accessed June 24, 2024. https://www.cnn.com/2020/06/24/health/bayer-monsanto-roundup-settlement/index.html
  19.  United States Environmental Protection Agency. Glyphosate. Updated September 11, 2023. Accessed June 25, 2024. https://www.epa.gov/ingredients-used-pesticide-products/glyphosate

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