An endocrine disruptor is a synthetic compound that mimics a natural hormone when it is absorbed by the body. It can turn on, turn off, or change normal signals. It can have the effect of altering normal hormone levels, triggering excessive action, or completely blocking a natural response. Any other bodily function controlled by hormones can also be affected. Some plant estrogens are naturally neutralized, others are easily excreted, and most do not accumulate in body tissue (unlike synthetic compounds and heavy metals). The half-life of a phytoestrogen is measured in minutes, while the half-life of various synthetic compounds, like DDT, may be years or even decades. Manmade chemicals that are known or suspected to influence the endocrine system are everywhere. All the latest and greatest, next-best-things that we now accept as “however-did-we-live-without-them” inventions are made with these chemicals.
They make our plastic products softer and easier to handle, our cosmetic creams and lotions smoother and longer-lasting, and our clothes and furnishings inflammable. They are used in clothing dye (especially denim!), cars and computer casings, Teflon coatings, and disinfectant bleaches. They are diffused throughout the atmosphere by the burning of industrial waste and leach into groundwater from landfills. Scientists are concerned because these chemicals biomagnify in the food chain. In humans, the natural level of circulating hormones needed to orchestrate bodily functions is relatively low. Synthetic endocrine disruptors are now being found in living tissue at dramatically higher concentrations than natural hormones. A CDC report from July 2005 found that the bodies of Americans of all ages contain an average of 148 synthetic chemicals. Do these chemicals really have any effect, or are they inert? Why can’t the body neutralize manmade chemicals? The good news is, we probably can, but the pace at which new chemicals are being introduced is outdistancing our body’s ability to adapt. We have a rigorous detoxification system in place in the form of our blood, lymph, liver, kidneys, intestines, lungs, and skin. But we are moving very quickly with manmade chemicals — experts estimate that 40 million pounds of hormonally active chemicals are produced in this country per annum, with 2000 new varieties introduced to market each year. Even the healthiest person may have trouble filtering this kind of load. There are many unanswered questions regarding the long-term effects of endocrine disruptors. Because they are a recent phenomenon, studies are just beginning to show possible connections. Research into the link between pesticides and frog deformities, fish sex reversals, and bird infertilities is well-documented. How this plays out further with mammals seems to be highly individualized, relative to variables such as age at exposure, genetics, level and length of exposure, gender, and detox capability. Some humans seem to be better at dealing with these substances, but we suspect that the increase in chemical and medical sensitivities, childhood cancers, infertility rates, learning disabilities, autism and mood disorders may relate in some way to the sea of endocrine disruptors in which we all swim. The hopeful aspect here is that these hormonally active contaminants do not seem to alter most people’s basic genetic blueprint — although our understanding of DNA and protein changes is expanding daily. We understand that what one inherits can be molded, and that while a person cannot change his/her eye color, certain genes directing metabolism can be changed — for good or bad. It is all too soon to tell just what the next generation will inherit, but in looking back, we now realize that DES affected not only daughters but sons as well, and in more ways than just genital abnormalities. New evidence points to epigenetic possibilities, meaning that we can pass along certain effects without actually changing our offspring’s DNA. In addition, not all genes will be expressed under all conditions — that is, some effects may only get turned on generations from now, or only under certain circumstances. The most common endocrine disruptor chemicals While we realize that the alphabet-and-number soup of all these chemicals can be quite confusing, even for those of us with a science background, we thought we would list some of the major offenders. Please feel free to skip this section if you prefer not to dwell on the negative. We include it because we believe information is power. • Bisphenol–A: A synthetic substance widely used to make polycarbonated plastics found in food and drink containers, the lining of tin cans, toys, baby bottles, dental sealants, flame retardants, and plastic wraps. This chemical easily leaches out into food and water. • Phthalates: Synthetic substances added to plastics to make them softer, more flexible and resilient. They also extend staying power. They are found in IV tubing, vinyl flooring, glues, inks, pesticides, detergents, plastic bags, food packaging, children’s toys, shower curtains, soaps, shampoos, perfumes, hair spray and nail polish. For more information, please refer to our article on holistic skincare. • Parabens: Compounds used as preservatives in thousands of cosmetic, food and pharmaceutical products. • PBDE’s (polybrominated diphenyl ethers): Found in flame retardants used on furniture, curtains, mattresses, carpets, television and computer castings. Categorized as a persistent organic pollutant (POP), this substance is stored in animal fats and thus found in dairy products, meat, fish, and human breast milk, and has been banned in several countries. It has also been detected in house dust. • PCB’s (polychlorinated biphenyls): Another group of highly toxic synthetic chemical compounds found on the list of POP’s, once used widely as insulation fluid in electrical transformers, lubricating oil in pipelines, and components of plastics and mixed with adhesives, paper, inks, paints and dyes. Since 1976 PCB’s have been banned in new products, but they are highly stable compounds that degrade very slowly, and these chemicals still persist. • Dioxin: Dioxin is a general name applied to a group of hundreds of chemicals that are highly persistent in the environment. The most toxic compound is 2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD. Dioxin is formed as an unintentional by-product of many industrial processes involving chlorine such as waste incineration, chemical and pesticide manufacturing, and pulp and paper bleaching. Small molecules are diffused into the atmosphere, then land on soil, where they are eaten by soil microbes. From there they pass up the food chain into meat, fish, and dairy products and breast milk. We absorb 90% of the dioxin in our bodies through food sources, though you won’t find it listed on any label. Levels have been decreasing since the 1990’s with environmental measures, but it is still probably the most prevalent toxic chemical in our environment. • Pesticides and herbicides: In particular, atrazine, simazine, and heptachlor and other organophosphates and organochlorines have been found to be toxic to the nervous system and to show damaging reproductive (e.g., decreasing sperm motility) and developmental effects.+ many more… • Heavy metals: Cadmium and arsenic are two heavy metals in widespread use whose endocrine disrupting mechanisms of action have been described. Mercury and lead are also implicated, and more studies are underway on heavy metals.