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Endocrine Disruptor Compounds: What We Know; What We Suspect
There is a wide and growing concern about environmental toxins and human health. These chemicals, the product of pesticides, plastics, fire-retardants, and industrial waste, are found in our sofas, our soil, our food. Their ability to persist in the environment and accumulate in our bodies over time is the reason why they pose such a serious health risk. This cumulative effect of environmental toxins, particularly on the health of developing fetuses and young children, has made them a public health issue.
Toxic chemicals are rarely found in amounts that can be seen or tasted. They are more often airborne molecules that exert a subtle, disrupting influence, usually at a hormonal level, that can have serious consequences. Leukemia, brain tumors, neurodevelopmental and behavioral problems, birth defects, low birth weight and other acute and chronic problems are among the possible short- and long-term consequences of childhood exposure to pesticides detailed in a recent report by the American Academy of Pediatrics.(1)
Dioxins, a group of chemically-related compounds that are persistent environmental pollutants, have been reported to be linked to genital abnormalities in male newborns whose mothers were exposed to them.(2) Other studies document poorer attention, a lack of fine motor coordination, and problem solving/thinking skills in children exposed to polybrominated diphenyl ether (PDBE) during fetal development and early childhood. (3)
Declining fertility has also been linked to chemicals in the environment. Sperm counts have declined over the last 50 years in some western countries and studies have suggested that couples exposed to polychlorinated biphenyls (PCBs) experienced decreased fertility.(4) Exposure to some organic pollutants that persist in the environment correlates with the development of type two diabetes, though no causal link has yet been found. Finally, the age at which girls reach puberty has been decreasing and concern has been raised that exposure to some organic contaminants is part of the problem.(5)
Unmasking the Threat of Endocrine Disruptors
What is going on and what do we know about the threat to our and our children’s health?
The compounds of concern are part of a group of chemicals called endocrine disrupting compounds (EDCs). They include natural and synthetic hormones, plant constituents, pesticides, compounds used in the plastic industry, and other industrial by-products and pollutants.
The list of substances which have been in the news for their proven or possible association with health problems includes PCBs, BPA, DDT, dioxin, phthalates and phytoestrogens.(6)
How Endocrine Disruptors Enter the Environment
EDCs enter the environment through numerous routes including hazardous waste sites, burning of industrial waste and improper dumping of industrial pollutants, exposure through use of food and beverage containers containing the chemicals, children’s toys, plastic pipes, lining of medical or even soup cans, medical supplies, and certain polymers used in dental treatment to name a few of the best studied exposure sites.
Some EDCs are transported long distances in the water and air supply. Some are rapidly degraded in the environment, while others persist for years. In fact, certain EDCs are stored in body fat and have been found in women’s breast milk and transmitted to their breastfeeding infants. Children are uniquely vulnerable to environmental toxins in the soil since they play outdoors, crawl on the ground, and put their fingers and toys in their mouths. Endocrine disruptors have been found in virtually all regions of the world, even minimally populated and non-industrialized areas.(7)
What Do EDCs Disrupt?
An endocrine disruptor is a chemical or compound that changes the way the endocrine system functions and causes negative health consequences to a living being or its offspring. They interfere with the formation, secretion, transport, action or elimination of natural hormones in the body. Hormones are responsible for how we grow and mature and age; they affect our behavior, fertility and cell metabolism.(8)
Exposures to EDCs cause different effects depending on when they occur. Developing fetuses and young children may be most vulnerable because they are at periods of rapid organ development, differentiation and growth but EDCs have been suspected of causing health problems in all age groups.
The endocrine system is responsible for the regulation of all body systems including the nervous system, reproductive system, and metabolic system. It is made up of glands — including the ovaries, testes, thyroid, pituitary and adrenals — that produce a variety of hormones that are released into the blood stream and travel to body tissues. In addition to the sex hormones estrogen and testosterone, there are thyroid hormone, growth hormone, insulin, the stress hormone cortisol and many others. Different hormones make reproduction possible, stimulate growth, build bone, make us hungry, move sugar into cells to provide energy and promote feelings of attachment. New hormones are still being discovered; at present, over 50 hormones have been identified.
There are two major classes of hormones. One class is made up of proteins, peptides, and modified amino acids; steroids form the second class. Each type of hormone is a chemical messenger, produced in one part of the body and acting somewhere else. In order to be appropriately effective, hormones must attach to specific receptors.