Chemicals that disrupt hormone function can have substantial and sometimes permanent impacts on health. Due to the nature of the body's endocrine system, effects can occur from very little exposure, particularly if it occurs before birth or during early life. We know that humans and animals are regularly exposed to endocrine disruptors. Scientists have been working to understanding where, when, and how such chemicals threaten the health of humans and wildlife.
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Below are answers to basic questions. Read our Related Articles to learn more about the history of the field and critical issues in science and policy.
Endocrine disrupting chemicals are chemicals that interfere with normal hormone action. For example, they can mimic or block hormones, and/or affect their production, their movement throughout the body, or their metabolism.
Hormones are chemicals such as insulin, thyroxin (thyroid hormone), estrogen, and testosterone. There are upwards of 50 different known hormones in the human body. Hormones send messages through the body by traveling to receptors in and on different cells, resulting in biological actions, such as ovulation or changes in blood sugar. The endocrine system is so finely tuned that it depends upon changes in hormone concentrations comparable to one drop in 20 Olympic swimming pools.
The endocrine system is the body’s exquisitely balanced system of glands, organs, and hormones that regulates such vital functions as body growth, response to stress, sexual development, production of insulin and utilization of glucose, metabolism, neurodevelopment, intelligence, behavior, sleep patterns, blood pressure, and the ability to reproduce.
Endocrine disrupting chemicals have been implicated in numerous adverse health outcomes, including those of the endocrine, reproductive, neurological, and metabolic systems. Examples include infertility, endometriosis, early puberty, breast and prostate cancer, thyroid disorders, Alzheimer’s and Parkinson’s disease, attention-deficit hyperactivity disorder, obesity, diabetes, asthma, immune disorders, and more.
Effects can occur from a very small amount of a chemical, and these ‘low dose effects’ can be different than the effects of higher doses. This makes the outcomes difficult to predict. Further, health effects may not show up until many years after exposure occurred, making it hard to connect cause and effect. We may even inherit susceptibilities from chemicals to which our parents, grandparents, or great-grandparents were exposed.
Endocrine disruptors are in our everyday products: from the personal care products and cosmetics we apply, to the chemicals we use to clean our homes, to the materials our homes, schools, and offices are built from. Most synthetic endocrine disrupting chemicals are derived from chemicals associated with fossil fuel extraction, processing, and/or burning. These include chemicals used as food additives, pesticides, plastics, dyes and more. Others are naturally occurring, such as phytoestrogens produced by plants.
Endocrine disrupting chemicals can be found in common products like canned food, perfume, plastic food containers, cosmetics, and furniture. They get into our bodies through food, water and dust, directly through our skin, from hand to mouth contact, and from the air we breathe.
Scientists and doctors can detect endocrine disrupting chemicals in blood, urine, stool, saliva, tears, perspiration, placental tissue, umbilical cord blood and the meconium of newborn babies. Endocrine disruptors have been found in every person tested, across world populations. Some endocrine disruptors remain in the body for years and others are excreted relatively quickly.
The age at which a person is exposed to endocrine disruptors is a primary factor in the level of risk. Exposure can be particularly harmful during times when the body undergoes a great deal of change, including during prenatal and early postnatal development, puberty, pregnancy, and menopause/andropause.
Further, infants and children are more susceptible to exposure because they spend more time closer to the ground where chemicals settle, have more hand to mouth behavior than adults, have greater food and water intake per unit of body weight, and their immune and metabolic systems are immature so they don’t process chemicals as well as adults. Exposure risk is also elevated in lower income areas, among minority populations, and in areas with fewer resources to reduce exposure.