Environmental Estrogens - Endocrine Distruptors

The terms below describe endocrine disrupters (endocrine disruptors), the synthetic chemicals and natural plant compounds that may affect the endocrine system (the communication system of glands, hormones and cellular receptors that control the body’s internal functions).

Many of these substances have been associated with developmental, reproductive and other health problems in wildlife and laboratory animals. Some experts suggest these compounds may affect humans in similar ways.

• Environmental estrogens
• Endocrine disrupters or endocrine disruptors
• Endocrine modulators
• Ecoestrogens
• Environmental hormones
• Xenoestrogens
• Xenobotics
• Hormone-related toxicants
• Endocrine-active compounds
• Phytoestrogens

Endocrine disrupters alter hormonal functions by several means. Substances can:

• mimic or partly mimic the sex steroid hormones estrogens and androgens (the male sex hormone) by binding to hormone receptors or influencing cell signaling pathways. Those that act like estrogen are called environmental estrogens.
• block, prevent and alter hormonal binding to hormone receptors or influencing cell signaling pathways. Chemicals that block or antagonize hormones are labeled anti-estrogens or anti-androgens.
• alter production and breakdown of natural hormones.
• modify the making and function of hormone receptors.

Exposure to these substances occurs throughout our lives from food, air, water, soil, household products and probably through breast milk and during development in our mother’s womb. The human health risks that may be associated with these low-level yet constant exposures are still largely unknown and highly controversial.

Foreign compounds although different in shape from natural hormones, can travel in the bloodstream, enter a cell, bind with a receptor and trigger gene expression. It is as if the imposters pick the lock, open the door and fool the receptor into letting them inside. Once bound with the receptor, the mimicker can produce a normal hormone response, cause an abnormal response or elicit no response as it blocks the receptor site and prevents natural hormones from binding.

Many widely-used synthetic chemicals and natural plant compounds can alter or interfere with the endocrine system. These substances can affect the endocrine system in many ways. For example, some compounds, referred to as environmental estrogens, can mimic or act like estrogens, the hormones that control female characteristics. Many can block or cancel out hormone actions and are called anti-estrogens or anti-androgens (the male hormones). Other compounds can both mimic and block hormones. Still others known as environmental disrupters or modulators can alter how natural hormones and their protein receptors are made, are broken down and perform. And to complicate matters even more, many chemicals have distinct effects in different species and organs and at different developmental stages.

Does EPA agree with the recommendations in Our Stolen Future? EPA claims they agree with many of the concerns raised in ‘Our Stolen Future‘ and have already taken steps to address a number of its recommendations.

The EPA agrees, for example, that pesticides should only be used when necessary and are working with other agencies and groups to reduce pesticide use and risk. These efforts include promoting Integrated Pest Management programs and safer pest control alternatives. They are apparently also working to implement recommendations from the National Academy of Sciences and others to provide greater assurance that our safety standards protect vulnerable populations, especially infants and young children, and improving our ability to screen for potential endocrine effects. Further, they are implementing new legislation that strengthens efforts in this regard and are developing an expanded research agenda. Finally, as the book points out, many of the chemicals of greatest concern have already been banned in the U.S. but may continue to be used in other countries. EPA claims they have taken a leadership role in international efforts to eliminate such persistent organic pollutants.

‘Our Stolen Future‘ also contains many practical suggestions and recommendations for people seeking to reduce their exposure to chemical risks. As with all suggestions affecting consumer choice, the final decisions will appropriately be made by individuals. Thus, the EPA does not necessarily believe that all of the book’s suggestions will be equally practical or appropriate for every person.

Plant vs. a Synthetic Estrogen

The crucial distinction is not whether a compound is a plant vs. a synthetic estrogen. Instead the focus should be on two issues:

• Does a specific estrogen like substance overcomes the body’s physiological defenses?
• Does it persist and bioaccumulate?

Persistent synthetic endocrine disruptors accumulate in body tissue to levels that are orders of magnitude of times higher than observed levels for phytoestrogens, and some are then transferred to the developing fetus.

The half-life (an estimator of how long a molecule of a compound will persist) of DDT or DDE in the body, or of PCBs, is measured in years and decades. The half-life of plant phytoestrogens is measured in minutes and hours.

Greenlee, AR, TE Arbuckle and P-H Chyou. 2003. ‘Risk factors for female infertility in an agricultural region’ reported a strong association between using herbicides and infertility in women. In their study population, women who were infertile were 27 times more likely to have mixed or applied herbicides in the two years prior to attempting conception than women who were fertile. Other factors, including smoking and exposure to passive smoke, steady weight gain during adult life, and consuming alcoholic beverages were also associated with infertility.

According to Edward N. Hanley Jr., MD, chairman, department of orthopaedic surgery, Carolinas Medical Center, Charlotte, N.C., women who smoke have significantly less bone mass, which may be due in part to nicotine’s inhibition of estrogen. Male smokers also are at increased risk of developing osteoporosis because smoking affects the production of bone cells.

In two studies funded by the National Institute of Environmental Health Sciences, researchers at Fox Chase Cancer Center in Philadelphia have demonstrated that two plasticizer compounds, BPA and BBP, are environmental estrogens capable of affecting gene expression in the mammary glands of young female laboratory rats exposed to the compounds through their mothers’ milk.

Raquel Moral, Ph.D., a postdoctoral associate in the Fox Chase laboratory of Jose Russo, M.D., presented the results on April 19, 2005 at the 96th Annual Meeting of the American Association for Cancer Research. “Development of breast cancer entails multiple events, in which estrogen appears to play an important role,” explained Russo. “Our laboratory has pioneered an in vitro system of cell transformation using estrogens and their metabolites as 1.hop.clickbank.net target=top>carcinogenic agents in human breast cells. Estrogenic agents involved in breast development and possibly in breast .hop.clickbank.net target=top>cancer may include foreign estrogens, or xenoestrogens, that are used in manufacturing a number of products.”

Special vulnerability of children

The developing nervous system of children appears to be particularly vulnerable to endocrine-disrupting chemicals, as evidenced by a variety of behavioral alterations in women who have consumed PCB-contaminated fish. Children’s developing reproductive organs are also at risk, since endocrine disruptors are suspected of being responsible, at least in part, for recently observed increases in the incidence of cryptorchidism and testicular cancer, as well as for the doubling in the incidence of hypospadias recently reported by the CDC.

Endocrine Disruptor Facts

• Children are widely exposed to endocrine disruptors in the environment, especially DDT, PCBs, and chlorinated pesticides such as chlordane.
• The incidence of hypospadias in newborn boys has doubled, with endocrine disruptors being a likely cause.
• The incidence of testicular cancer in young men has increased by 60%, with endocrine disruptors being a likely cause.
• The incidence of breast cancer is up in women. The risk of breast cancer is related to women’s body burdens of DDT and PCB.
• Fetal exposure to PCB reduces intelligence.
• Endocrine disruptors may be a factor in the increasing incidence of premature puberty in young girls.

Children’s exposures to newly developed chemical toxins, in combination with the triumph of vaccines and antibiotics, have changed the face of childhood illness. The classic infectious diseases have largely been conquered. They have, however, been replaced by chronic, complex, handicapping conditions that affect multiple organs. In children, these diseases are largely unknown and have not been adequately studied. But environmental factors are strongly suspected to play an etiologic role, and these urgently need to be investigated.

Asthma incidence and mortality among both children and adults have increased substantially over the past decade in the United States. These increases are particularly evident in urban localities. In New York, Chicago, Los Angeles, and other major cities, asthma has become the leading reason for children’s admission to the hospital.

Urban air pollution, especially ground-level ozone and fine particulates, appear to be important contributors to the upward trend in asthma. Indoor air pollution, including insect dust and environmental tobacco smoke, is an additional trigger.

Each year in the United States, an estimated 8,000 children up to age 14 are diagnosed with cancer. Leukemia and brain tumors are the most common malignancies in childhood. Cancer is the second most common cause of death after injuries in American children.

The death rate from childhood cancer has declined dramatically in recent years in the United States-thanks to the advent of vastly improved approaches to rem.hop.clickbank.net target=top>cancer treatment. But the occurrence of new cases of cancer among children- the incidence rate-has been steadily increasing. This upward trend has been most strongly evident for acute lymphoblastic leukemia and brain cancer, the two most common forms of cancer among American children.

These increases in the incidence of childhood cancer have not been explained. However, they are too rapid to reflect genetic changes. Nor is better diagnostic detection a likely explanation. The strong probability exists that environmental factors are playing a role. It is essential that research to identify the specific environmental causes of childhood cancer be undertaken and that the pace of this research be accelerated.

Each year, tobacco kills 350,000 Americans. Tobacco is a major threat to the health of children, who are at risk from both active smoking and passive exposure to cigarette smoke.

Smoking among children typically starts early. Ninety percent of all cigarette smoking begins before the age of 18 years.

More than 70 percent of all American high school students have tried cigarettes. Seventeen percent are regular smokers. Over the past decade, the number of boys who start smoking has declined. But there has been a steady increase in the number of girls and young women who smoke.

Passive smoking is also a hazard to children. Children exposed to passive smoke have more bronchitis, more pneumonia, and more viral respiratory infections than nonexposed children. The frequency of infection is a direct consequence of the amount of smoke in the home. Children who live with two smoking parents have more respiratory infections than children who have only one smoking parent. Maternal smoking has a stronger effect on children’s respiratory infections than smoking by the father. The lowest rates of lung infection and asthma are found in the children of parents who do not smoke at all.

Smoking during pregnancy poses a serious danger to the unborn child. Study after study has shown that among women who smoke, the likelihood of giving birth to a premature, low-birth-weight infant is substantially higher than among women who do not smoke. Women who smoke are also at increased risk of a pregnancy ending in miscarriage.

Women who smoke often have a more difficult time conceiving than nonsmoking women of the same age. And their risk of not becoming pregnant at all - of sterility - is elevated. Finally, the children of parents who smoke have a higher than normal risk of death from sudden infant death syndrome (SIDS).

Children’s changing environment

• Children are more heavily exposed to environmental toxins than adults. Pound-for-pound, children breathe more air, drink more water, and eat more food than adults. Thus, they are more exposed to whatever toxins are present in those media. Children’s exposures are further increased by the fact that they tend to play close to the ground and to engage in repeated hand-to-mouth activity.
• Children are less able to metabolize and excrete most toxic substances.
• Children’s rapidly developing organ systems-the central nervous system, reproductive organs, immune system, and lungs-are highly susceptible to toxic insult.
• Because children have more future years of life than adults, they are more susceptible to chronic, multi-stage diseases such as cancer or neurodegenerative disease that may be triggered by early exposures.

Daily explosure

The most insidious of the endocrine disruptors (EDs) are man-made synthetic chemicals. We are routinely exposed to them in most areas of our daily lives at home, work and play.

Known and suspected EDs come in things we have been led to believe have been thoroughly tested for the safety of our health and environment. These types of products include

• cosmetics
• sunscreens
• perfumes
• soaps
• detergents
• solvents
• dental sealants
• pharmaceuticals such as birth control pills
• clear plastic baby bottles, and some water bottles

The list of goes on to include many chemicals in plastics (PVC, polystyrene aka Styrofoam, and others) and pesticides (Monsanto’s Roundup and many others).

A few heavy metals are included - arsenic, cadmium, lead, mercury. Other known EDs are the 209 PCBs (polychlorinated biphenyl), 75 dioxins, and 135 furans.

The creation can be intentional and/or as byproducts of industrial processes such as the production of paper that uses chlorine bleaching, as well as the incineration of chlorine containing products such as PVC burned in incinerators, residential backyard barrels, or accidentally in building fires.

PVC is made into toys, teethers, clothing, raincoats, shoes, building products such as windows, siding, roofing, and flooring. Other uses are for hospital blood bags, IV bags, tubing and other medical devices. Polystyrene, another ED, is made into food containers for meats, fish, cheeses, yogurt, foam and clear clamshell containers, foam and rigid plates, clear bakery containers, packaging “peanuts”, foam packaging, audio cassette housings, CD cases, disposable cutlery.

Other specific EDs are oil refining, burning coal and oil for energy, all car and truck exhaust, cigarette smoke.

Chemical manufacturers claim that the scientists who urge caution with regards to EDs are but hysterical sensationalists. Something they like to scare us with is that ending production of these toxic chemicals would take jobs away from people. They also say that because only animal tests have been done, no proof exists that humans are being affected as other animals are. But through studies of industrial workers’ health and accidents enough has been learned to strongly implicate EDs. When industry gets really scared they debunk any negative claim as being ‘junk science.”

What you can do to avoid endocrine disruptors

Always question yourself before buying, “Do I really need this product?” If you really need it, then ask, “What can I use that’s less toxic?”

• Don’t smoke or drink alcohol. Especially when pregnant. It can cause permanent damage to you and the unborn child.
• Don’t use lawn chemicals or any pesticides. Especially when pregnant. Don’t even think of being near them. Lawns are healthier without them.
• Don’t use makeup, hair sprays & coloring products or nail polish Especially when pregnant. Enjoy your own body and not the image that the media says you should want.
• Avoid using strong chemicals, glues, paints, nail polish and remover, floor & carpet cleaners.
• Get rid of all those name brands and use earth friendly products spareingly. If you must use chemicals then wear industrial quality, gloves, eye protection and a mask with filters approved for each chemical being used. Once again? definitely NOT when your pregnant!
• Don’t heat food or eat hot food in plastic containers, even the ones frozen dinners now come in. This includes Teflon coated cookware.
• Chemicals from the plastic can be ingested with the food and could cause great problems for the unborn and you.
• Purchase fresh organic produce, meats and milk free from rBGH

Further reading

Web home for the authors of ‘Our Stolen Future’

Endocrine Disruptors and Reproductive Development

Beyond Pesticides website

e.Hormone website

List of Widespread Pollutants with Endocrine-Disrupting Effects