The body’s endocrine system is a network of glands that produce hormones, which act as chemical messengers. Hormones regulate a vast array of bodily processes, including growth, metabolism, sleep, and reproductive functions. Exogenous chemicals that can interfere with this system are known as endocrine disruptors. These substances are found in numerous everyday products and throughout the environment.
How Endocrine Disruptors Interfere with Hormones
Endocrine-disrupting chemicals (EDCs) interfere with hormonal pathways through several mechanisms. One primary way they act is by mimicking the body’s natural hormones. These chemicals have a structure similar enough to endogenous hormones that they can bind to hormone receptors on cells, initiating an unneeded response. This is like a “wrong key” fitting a lock and starting a process at an inappropriate time.
Another method of interference is blocking, where an EDC binds to a hormone’s receptor but fails to activate it. This binding prevents the body’s natural hormones from accessing their own receptors to carry out their functions. This action is analogous to a key breaking off inside a lock, physically obstructing the correct key.
Some EDCs also disrupt the endocrine system by altering the lifecycle of natural hormones. They can interfere with the synthesis, transport, metabolism, or excretion of hormones. For example, a chemical might inhibit an enzyme responsible for breaking down a hormone, leading to an excess of that hormone and an overstimulation of its pathway.
Common Endocrine Disrupting Chemicals and Their Sources
Bisphenols, with bisphenol A (BPA) being the most well-known, are used to make polycarbonate plastics and epoxy resins. These materials are found in the lining of food and beverage cans, some plastic containers, and on thermal paper used for receipts.
Phthalates are used to increase the flexibility and durability of plastics like polyvinyl chloride (PVC). They are found in products like vinyl flooring, food packaging films, and medical tubing. Certain phthalates are also used as solvents in synthetic fragrances, so they appear in personal care products like perfumes and lotions, often listed only as “fragrance.”
Per- and polyfluoroalkyl substances (PFAS) are a family of chemicals known for their resistance to grease, oil, water, and heat. They are used in non-stick cookware, water-repellent clothing, stain-resistant carpets, and furniture. PFAS are also used in food packaging, such as microwave popcorn bags and fast-food wrappers, to prevent grease from leaking through.
Many agricultural chemicals, including certain pesticides and herbicides, have endocrine-disrupting properties. While designed to be toxic to pests, their mechanisms can affect other organisms, including humans. Exposure occurs through residues on non-organic produce or through contaminated soil and groundwater.
Parabens are used as preservatives in cosmetics, pharmaceuticals, and food products. They are found in moisturizers, makeup, and numerous processed foods and can be identified on labels by names like methylparaben or propylparaben. Like phthalates, they are absorbed through the skin or ingested.
Health Implications of Exposure
The timing of exposure to EDCs is important, with developmental stages like in the womb, infancy, and puberty being periods of heightened vulnerability. Because these chemicals can interfere with sex hormones, reproductive health is a primary area of concern. In women, exposure is linked to infertility, endometriosis, and early puberty, while in men, it is associated with reduced sperm quality and abnormalities in sex organs.
The developing fetus and child are uniquely susceptible to EDC effects, as hormonal interference can have lasting consequences. Exposure during these sensitive windows is linked to impacts on neurodevelopment, which may manifest as learning disabilities or behavioral changes. EDCs can also alter normal growth patterns and disrupt the timing of puberty.
Certain chemicals are considered “obesogens” because they may promote obesity by interfering with the body’s weight-control mechanisms. This disruption can alter how the body creates and stores fat. Associations have also been found between exposure to some EDCs and an increased risk for type 2 diabetes and metabolic syndrome.
Hormonal interference can also influence the risk of developing certain cancers, particularly those that are hormone-sensitive. Exposure to EDCs that mimic estrogen, for example, is associated with an increased risk for breast and ovarian cancer. Disruptions to androgen pathways have been connected to a higher risk of prostate cancer, and some EDCs are linked to an increased risk of thyroid cancer.
Strategies for Reducing Exposure
While completely avoiding endocrine disruptors is nearly impossible, specific choices can significantly reduce personal exposure.
- Minimize contact with plastics and can linings in the kitchen, especially when heating food. Use glass, ceramic, or stainless steel containers for food storage and microwaving, and opt for fresh or frozen foods over canned goods to reduce BPA exposure.
- Read labels on personal care products and choose items labeled “paraben-free” and “phthalate-free.” Since phthalates are often hidden in fragrances, select “fragrance-free” products or those scented only with natural essential oils.
- Reduce household dust, which can be a reservoir for EDCs like PFAS. Dust frequently with a damp cloth and vacuum regularly with a HEPA filter to capture these particles. Filtering drinking water can also remove contaminants like PFAS and pesticide residues.
- Wash all fruits and vegetables thoroughly to remove surface pesticide residues. Choosing organic produce can further reduce exposure to synthetic pesticides, and reducing high-fat meat and dairy consumption may lower your intake of EDCs that accumulate in animal fat.