Endocrine Disruptors

This may be a topic that we all know a little about, but never took a time to look deeper into it. At least this is the way I feel about endocrine disruptors. So today I decided to write a few things on this subject in order to bring more attention to it.

Hormones are chemical messengers released by glands or cells that transmits a signal from one cell to another. Hormones work in conjunction with many organs and systems to help control and maintain: body energy levels, reproduction growth and development, homeostasis (internal balance), response to surroundings, stress and injury. So as the name might imply, endocrine disrupting chemicals may interfere with the body’s own hormone signals due to their structure and activity, and therefore mess up with the body's normal function.

Endocrine disruptor are found in food and beverages, medicines, pesticides, and cosmetics. So, exposures may be through the diet, air, skin, and water. Some environmental endocrine disrupting chemicals, such as the pesticide DDT, dioxins, and polychlorinated biphenyls (PCBs) are highly persistent and slow to degrade in the environment making them potentially hazardous over an extended period of time.

Endocrine disruptors can interfere with the body's natural balance in three ways. First, they can mimic naturally occurring hormones in the body like estrogen, androgen, and thyroid hormones, potentially producing over-stimulation. Or they can bind to a receptor within a cell and block the endogenous hormone from binding this same cell therefore, impeding the body to respond properly to hormonal stimulus. And lastly, they can interfere or block the way natural hormones are made, for example, by altering their metabolism in the liver.

Who are they?

• DES (Diethylstilbestrol)  is a synthetic form of the female hormone estrogen. It was prescribed to pregnant women between 1940 and 1971 to prevent miscarriage, premature labor, and related complications of pregnancy. DES use was discontinued after studies showing that it was not effective in preventing these problems. Furthermore, studies showed that prenatal exposure to DES increases the chance of cervical and breast cancer as well as adenocarcinoma. And women who took DES during pregnancy have an increased risk of breast cancer.

• Dioxins are a group of chemically-related compounds that are persistent environmental pollutants. They are found throughout the world in the environment and they accumulate in the food chain, mainly in the fatty tissue of animals. More than 90% of human exposure is through food, mainly meat and dairy products, fish and shellfish. This highly toxic chemical can cause reproductive and developmental problems, damage the immune system, interfere with hormones and cancer. The developing fetus is most sensitive to dioxin exposure. The newborn, with rapidly developing organ systems, may also be more vulnerable to certain effects. Some individuals or groups of individuals may be exposed to higher levels of dioxins because of their diets or their occupations for example, meat eaters and workers in paper industry respectively. 
  A North American eating a typical North American diet will receive 93% of their dioxin exposure from meat and dairy products (23% is from milk and dairy alone; the other large sources of exposure are beef, fish, pork, poultry and eggs).  The best way to avoid dioxin exposure is to reduce or eliminate the consumption of meat and dairy products.
  

• PCB's (Polychlorinated biphenyls) belong to a broad family of man-made organic chemicals known as chlorinated hydrocarbons. PCB's were used in hundreds of industrial and commercial applications. Although no longer commercially produced in the United States, PCBs may be present in products and materials produced before the 1979 PCB ban. Products that may contain PCBs include: transformers and capacitors, voltage regulators, switches, electromagnets, oil used in motors and hydraulic systems, cable insulation, plastics, carbonless copy paper, floor finish, among others. PCBs have been shown to cause cancer in animals and a number of serious non-cancer health effects, including effects on the immune system, reproductive system, nervous system, endocrine system, liver toxicity, high cholesterol and high blood pressure.

• DDT (dichloro-diphenyl-trichloroethane) was developed as the first of the modern synthetic insecticides in the 1940s. It was initially used with great effect to combat malaria, typhus, and the other insect-borne human diseases among both military and civilian populations and for insect control in crop and livestock production, institutions, homes, and gardens. DDT's quick success as a pesticide and broad use in the United States and other countries led to the development of resistance by many insect pest species. Today, DDT is classified as a human carcinogen by U.S. and international authorities. This classification is based on animal studies in which some animals developed liver tumors.
  DDT is known to be very persistent in the environment, will accumulate in fatty tissues, and can travel long distances in the upper atmosphere. Since the use of DDT was discontinued in the United States, its concentration in the environment and animals has decreased, but because of its persistence, we are still be ingesting its residues from the environment.

• DEHP (Di (2-ethylhexyl) phthalate) is a high production volume chemical used in food packaging, some children’s products, and some polyvinyl chloride (PVC) medical devices. DEHP may pose a risk to human development, especially critically ill male infants. 

• BPA (Bisphenol A)  is a chemical produced in large quantities for use primarily in the production of polycarbonate plastics and epoxy resins. This synthetic chemical with estrogen-like effects, is used in products such as baby bottles, water bottles, eyeglass lenses, medical equipment, toys, CDs/DVDs, cell phones, consumer electronics, household appliances, sports safety equipment, airplanes, and automobiles. Epoxy resins containing BPA are used as liners for most food and beverage cans, adhesives, industrial protective coatings, and automotive primers. BPA is also used to make dental sealants and flame retardants. Some animal studies suggest that infants and children may be the most vulnerable to the effects of BPA in the brain, behavior, and prostate gland. Parents can make the personal choice to reduce exposures of their infants and children to BPA by not microwaving polycarbonate plastic food containers, reducing the use of canned foods, opting for glass, porcelain or stainless steel containers, particularly for hot food and liquids. Use baby bottles that are BPA free!!! Some, but not all, plastics that are marked with recycle codes 3 or 7 may be made with BPA.
  
  
  Phytoestrogens are naturally occurring substances in plants that have estrogen-like activity. Estrogen is a hormone necessary for childbearing and is involved with bone and heart health in women. However, higher exposure to estrogens over a lifetime is linked with increased breast cancer risk. More than 300 foods have been shown to contain phytoestrogens. Most food phytoestrogens are from one of three chemical classes, the isoflavonoids, the lignans or the coumestans. Isoflavonoid phytoestrogens are mostly found in soybeans and soy products are the major dietary source of this type of phytoestrogens. Lignan phytoestrogens are found in high fiber foods such as cereal brans and beans; flaxseeds contain large amounts of lignans. The coumestan phytoestrogens are found in various beans such as split peas, pinto beans, and lima beans.When eaten in moderation and in its natural forms this phytochemicals might pose great health benefits for you. They are only harmful when eaten in large quantities and usually on a more processed and isolated form.
  
  
  
  
  For those interested in the subject of soy and breast cancer, here is a great summary of what you might be looking for by Dr. Melina Jampolis on the notes of cancer nutrition expert Rachel Beller:
  
  

  " Beller explained that while phytoestrogens are similar to human estrogens, their effect on human estrogen levels has not been well-researched because plant estrogens are 1,000 times weaker than the estrogen produced in our bodies.

  Many studies suggest that soy isoflavones' estrogen-like effects are probably too weak to have any significant consequence on breast tissue in healthy women - that includes breast cancer survivors.

  Regarding the association with breast cancer, Beller points to a 2011 study published in Cancer Epidemiology, Biomarkers & Prevention that found soy to be safe and favorable, even for breast cancer survivors, when eaten in its natural, unprocessed state - for example, tofu, tempeh, edamame, miso soup.

  In fact, experts agree that fermented soy (miso, tempeh) is good for you. The fermentation process alters the chemical makeup of soy, which reduces the level of isoflavones by as much as 300%.

  Therefore fermented soy foods have three times less of the chemical in question.

  While this study does not conclusively establish the safety of soy, phytoestrogens aside, soy is not only an excellent source of heart healthy plant-based protein, which is encouraged in the latest dietary guidelines for Americans, it also contains dozens of nutrients that also appear to help fight cancer development.

  These nutrients can protect cells from becoming damaged, encourage faulty cells to die instead of reproducing, regulate cell growth and even improve cell communication. These are all things that help strengthen your body against cancer and heart disease.

  A study has also shown that consumption of soy early in life may help protect against breast cancer later in life, even if it may be more questionable for post-menopausal women.

  What's also noteworthy is that Asians have been eating soy foods in large amounts for centuries, and their traditional soy-rich diets are associated with lower risks of breast and prostate cancer than Western diets.

  Beller goes on to say that the "bad rap" that soy's been getting is due to the fact that when we hear something's "good for you," we process it to the max, extract the good stuff and concentrate it, which basically makes it lose its original identity.

  Skip the processed soy foods and supplements, especially if you have a history of breast cancer.

  The bottom line: If you have no history of breast cancer, there is no known high or harmful amount of phytoestrogens, and foods such as unprocessed soy are an important part of a healthy diet.

  If you have a history of breast cancer, as with nutrition in general, you should not focus on a single food or nutrient. The key is moderation.

  The phytoestrogens consumed by eating moderate amounts of relatively whole and unrefined forms of soy foods (two to three times a week) can be considered part of a healthy, complete diet.

  
  
  source: American Cancer Society, U.S. Environmental Protection Agency, World Health Organization