Health Effects of Environmental Endocrine Disrupters

The greater an individual's exposure to Endocrine Disrupting Chemicals (EDCs), the greater the risk of chronic disease, with the most concern for children, pregnant women, and anyone with a compromised immune system.

With Vincenzo Marotta, MD

Endocrine disrupting chemicals (EDCs) are environmental chemicals that mimic, block, or interfere with hormones in the body. Increasing exposure to  EDCs over the past 20 years appear responsible for the growing number of people with infertility, diabetes, early onset of puberty in girls and early menopause in women, cancer, birth defects, and neurobehavioral disorders, according to a statement issued by the Endocrine Society and IPEN, a global network of more than 500 public interest NGOs in more than 100 countries around the world.1

These environmental toxins have been found in our air, water, and soil as well as in a range of household products, including children’s toys, furniture, and beauty products.

While it is not clear exactly how many EDCs exist, the most common EDCs include:

  • Bisphenol A (BPA) used in certain children’s toys, plastic bottles, and food containers, food can linings, and cash register receipts
  • Dichlorodiphenyltrichloroethane (DDT, which is now banned) and other pesticides
  • Flame retardants used in certain furniture and floor coverings
  • Polychlorinated biphenyls (PCBs), which were used in electronics and building materials before being banned at the end of the 1970s
  • Phthalates in beauty products and plastics
  • Triclosan used in antibacterial products

Known EDCs such as PCBs, BPA, and phthalates are found in blood, fat, and umbilical cord blood samples taken from people around the world. While some EDCs (eg, DDT and PCBs) have been banned, these chemicals may remain in the environment and food supply for decades. Some EDCs may be stored in fat cells for years after exposure and may be passed on to children during pregnancy or when breastfeeding.

In contrast, BPA does not accumulate in the body, and studies have shown that minimizing the use of canned foods and plastic containers can reduce BPA levels found in the body. However, BPA is still used in so many products that the U.S. Centers for Disease Control and Prevention has estimated that more than 96% of Americans have BPA in their bodies.2

The Impact of EDCs on Hormones, and Health

Endocrine disrupting chemicals may bind to an endocrine hormone’s receptor, activating the hormone’s production and triggering physiological processes. Conversely, some EDCs block endocrine hormones by binding to their receptors and blocking normal activation even in the presence of the natural hormones.

The concern has grown since even a low level of exposure to EDCs can affect body functions, particularly in the most vulnerable populations including infants and children, pregnant women, and those who are immune compromised or frail.

Of particular note, recent studies have shown the following:3-11

  • Exposure to pesticides like DDT can increase the risk for cardiovascular disease and inflammation in women who are premenopausal.
  • Exposure to BPA has been linked to an increased risk of infertility, cancer, and metabolic disorders, including diabetes.
  • Exposure to BPA during pregnancy may increase offspring’s risk for developing diabetes or cardiovascular disease later in life.
  • Early onset of menopause has been linked to 15 chemicals, including phthalates and PCBs.
  • PCBs can interfere with thyroid hormone action in pregnant women, which may affect brain development in fetuses.
  • Men, women, and children exposed to high levels of phthalates may have reduced levels of testosterone.
  • Exposure to EDCs has been estimated to cost between 150-260 billion euros per year in the European Union due to contributing to a number of diseases and health conditions.

Two Endocrine Disrupters Linked to Thyroid Cancer

A red flag has just been raised about the potential for harm from exposure to two common pollutants: bisphenol AF (BPA) and phytates (diethylhexylphthalate). In a study published in Chemosphere, the authors evaluated the blood levels of more than 14 EDCs and found a significant link between these two endocrine disrupters and thyroid cancer.12 

The researchers identified 55 patients from five different medical sites across Italy who were seeking treatment for thyroid nodules; their blood was evaluated for levels of these EDCs.12  What they found was in patients with high levels of both BPA and phthalates in their blood, there was a dose-response effect regarding the development differentiated thyroid cancer.  No effect was found with the patient's level of thyroid stimulating hormone (TSH).

In fact, the risk of developing thyroid cancer appears 14-fold higher in the individuals who have been exposed to low doses of these environmental toxins,12 according to Dr. Vincenzo Marotta, the lead study author, who is an oncologist from  IRCCS National Cancer Institute in Naples, Italy.

For any patient with a thyroid nodule, physicians might recommend avoiding regular contact with these offending substances by adopting a few new behaviors:   

  • Avoid contact with BPA by purchasing a BPA-free, reusable water bottle to take whenever leaving the home to avoid the need to buy a plastic bottle of water while out.
  • Suggest not handling cash register receipts; instead, they can be emailed, or patients can pay by credit card to have proof of the purchase.
  • Choose frozen over canned foods as much as possible; and check the containers as many manufacturers have already changed the lining in cans to remove the bisphenol so canned tuna, for example, can still be eaten so long as the contain declares it is "BPA-free".

Avoiding phthalates is much harder as this chemical is present in commonly used plastic takeout food and beverage containers, and vinyl (eg, shower curtains, flooring, mini-blinds, inflatable mattresses, diaper mats, air-fresheners, and raincoats and rain boots).

For more information, direct patients to the Environmental Working Group’s guides to beauty products, cleaning products, and foods so they are able to develop a plan to switch away from products they commonly use that contribute EDCs. 

Compelling Reasons to Actively Reduce Patients' Exposure

Bisphenol A (BPA) is a chemical that is primarily used to make polycarbonate plastic and epoxy resins, both of which are commonly used in consumer products. Polycarbonate is a hard clear plastic that is used in electronic products, automotive products, and many household products, including food storage containers. It also is commonly used in a range of medical devices, including syringe barrels, components of dialysis equipment, and blood oxygenation equipment.

Epoxy resins are commonly used in coating applications. For example, epoxy resins are the most common type of protective coating used in food and beverage cans. The coating is applied to prevent erosion of the can and possible contamination of food and drink from metal or bacteria. Epoxy resins have been used in food cans for 30 to 40 years, and polycarbonate and epoxy resins have been used in numerous applications for approximately 50 years, said Steven G. Hentges, PhD, is Executive Director of the Polycarbonate/BPA Global Group of the American Chemistry Council.

In general, government agencies, including the US Food and Drug Administration (FDA) maintains that BPA is safe when used in the form of polycarbonate or epoxy resins for food contact applications.13  Based on the FDA’s ongoing safety review of scientific evidence, “the available information continues to support the safety of BPA for the currently approved uses in food containers and packaging.”14 

Pharmacokinetics and Metabolism of BPA
Pharmacokinetic and metabolism data from the National Toxicology Program (NTP), FDA, and other researchers show that when BPA enters the body through food exposure, it is metabolized almost completely into a biologically inactive metabolite at the point of absorption in the intestinal wall and the liver.4,5

This resin code found on plastic containers indicates that BPA may be present.

Exposure
Extensive data from the Centers for Disease Control and Prevention and the National Health and Nutrition Examination Survey indicate that human exposure to BPA is extremely low.Typical human exposure is in the range of approximately 25 nanograms of BPA per kilogram of body weight per day.7 Together, this data shows that, on average, we are exposed to low levels of BPA, and what does enter the body is metabolized and quickly eliminated from the body typically on the same day as exposure.

Even under high temperatures, the amount of BPA that could be released from polycarbonate plastic and epoxy resins is still well below governmental limits for alarm despite public concern.

Toxicity
Data on the toxicity of BPA is more controversial, but the intensity of public pressure has generated a willingness by manufacturers to remove this chemical from many products including those of plastic bottles.

Even so, carcinogenicity studies by the National Toxicology Program show that BPA does not appear to be carcinogenic.11 However, like any chemical, it will cause systemic toxicity at high doses and is likely to have the greatest negative effect in babies, children and pregnant women where lower levels of exposure may be sufficient to cause harm.

 

Continue Reading:
Earlier Menopause Linked to Exposure to Endocrine Disrupting Chemicals
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