What Are Endocrine-Disrupting Chemicals?
In 2009, a group of U.S. scientists released a statement alerting the public to an urgent issue: chemicals that target our hormones are circulating in our environment — and they’re a problem for our health.
Since then, a soup of chemicals found in our water, food, blood, and urine have all been labeled endocrine disruptors. Widespread exposure to these chemicals over the last several decades has coincided with an increase in chronic diseases in young people, including breast cancer, raising the question: Are these chemicals linked to breast cancer?
Endocrine disruptors
Endocrine-disrupting chemicals (EDCs) — sometimes called endocrine disruptors or hormone disruptors — are chemicals or mixtures of chemicals that interfere with the body’s endocrine system. This system uses hormones as messengers to tell cells throughout the body what to do, coordinating many of the body’s functions. Some EDCs mimic or block hormones, while others cause too much or too little production of a certain hormone. Endocrine disruptors have been linked to obesity, diabetes, attention-deficit/hyperactivity disorder (ADHD), infertility, thyroid function, breast cancer, and more.
The Endocrine Society estimates that more than 1,000 chemicals may act as endocrine disruptors, including those found in:
Pesticides: Chlorpyrifos and other pesticides are used in large-scale agriculture and home gardening to protect crops from insects and pests. Pesticides also include insect sprays used in homes.
Flame retardants: Brominated flame retardants are used as a coating in furniture, carpet padding, electronics, kitchen appliances, car seats, and more
Plastics: Bisphenol A (BPA) and other bisphenols are used to make plastic more rigid, while phthalates make plastic more flexible. Perfluoroalkyl and polyfluoroalkyl substances (PFAS), sometimes called “forever chemicals,” are used in food packaging and nonstick coatings.
Fossil fuels: Polyaromatic hydrocarbons (PAHs) are created by any combustion of organic materials, like burning fossil fuels or cooking at high temperatures.
Cosmetics: Some phthalates and parabens, a group of preservatives known to disrupt hormones, are present in cosmetics.
Most people are exposed to endocrine disruptors every day. For example, pesticides end up in produce, PAHs end up in the air, and PFAS settle in the dust at home.
Hormones affect growth and development, reproduction, metabolism, energy, mood, and more. When this system is disrupted, certain diseases or disorders may arise.
Hormones play a role in the development of most breast cancers. Estrogen and progestin, a synthetic progesterone used in birth control and menopause hormone therapy, can cause breast cells to grow rapidly. Most breast cancers have hormone receptors, meaning they grow in response to estrogen or progesterone.
The longer someone is exposed to the hormones estrogen and progesterone, the higher their risk is for breast cancer. Lifetime exposure to hormones is influenced by the timing of their first period, pregnancy history, menopause — and possibly exposure to endocrine-disrupting chemicals that mimic estrogen or progesterone or increase their production.
Hormone disruptors and breast cancer
Hormone-disrupting chemicals increase the risk of developing breast cancer in a few different ways.
They interfere with breast development
Some hormone-disrupting chemicals are known to interfere with breast development during puberty, pregnancy, and breastfeeding. These changes may increase breast cancer risk. Some examples of hormone disruptors that interfere with breast development include some phthalates, BPA and other bisphenols, flame retardants, PFAS, and pesticides. These chemicals can also affect the timing of puberty and the ability to breastfeed. Scientists are studying whether they affect breast density.
They increase estrogen
Some endocrine disruptors, like the herbicide atrazine, may increase the activity of the enzyme aromatase, which converts androgen hormones into estrogen. For people with breast cancer with estrogen receptors, this extra boost of estrogen from aromatase helps cancer grow.
Researchers have shown that in cells that mimic how hormones are made in people, BPA and other endocrine disruptors increase estrogen production, even at low doses.
Some EDCs also damage DNA
Some endocrine disruptors also have other biological activity. Some are carcinogens, meaning they likely cause cancer by damaging or changing cell DNA in ways that may eventually lead to cancer. Exposure to a carcinogen doesn’t always lead to cancer and can depend on the dose of exposure, how the exposure happened, and a person’s genetic makeup. Diethylstilbestrol (DES), a drug used to prevent miscarriages from the 1940s through the 1960s, is an EDC and a carcinogen.
Steps you can take to reduce your risk
While endocrine disruptors are widespread and you can’t eliminate all EDCs from your life, there are ways you can reduce your exposure to them.
Reduce dust in your home
Dust surfaces in your home with a damp cloth once a week to reduce exposure to EDCs that settle in dust.
Regularly wash your hands with soap and water to avoid touching your face and mouth with dust.
Leave your shoes at the door to reduce tracking in dust from outside.
Vacuum your home once a week, preferably with a vacuum cleaner with a high-efficiency particulate air (HEPA) filter (removes airborne particles like dust, pollen, dirt, and bacteria).
Consider alternative food options
Avoid microwaving plastic food containers to reduce plastic exposures, since chemicals leach from plastic when heated.
If you can, avoid canned foods and opt for fresh foods instead.
If you can, switch to organic, hormone-free produce; if switching to only organic produce isn’t possible, try switching out just spinach or strawberries, some of the most pesticide-contaminated produce in the U.S. You can also wash or peel your produce to remove pesticide residues.
Use a vent fan when cooking.
Check the ingredients in your cosmetics
Avoid cosmetics with “fragrances” or “parfum,” which can include phthalates or other hormone disruptors
Consider cutting down on the amount of cosmetic and skincare products you use, since hormone disruptors in cosmetics aren’t regulated in the U.S. (The European Union does have stricter chemical regulations).
