Hormone trickery: endocrine disrupting chemicals

The endocrine system consists of many glands distributed throughout the body, producing more than 50 hormones that are released into the bloodstream or the fluid surrounding cells. Receptors in various organs and tissues respond to these hormones in specific and vital ways that control metabolism, immunity, development and growth, reproduction and behavior.

Since the beginning of the industrial age in the nineteenth century and the dawn of industrial agriculture in the twentieth century, humans have manufactured thousands of chemicals that serve many purposes. The effects of these chemicals on human health were largely ignored until the 1960s. Yet since then, and despite a convincing body of research showing their negative effects on human health, little has been done to regulate or limit the production and distribution of these chemicals.

Over the last 50 years, two major assumptions about these chemicals have been gradually debunked:

1) that exposure to very small amounts is not harmful; and

2) that synthetic chemicals could not disrupt hormonal balance and cause disease[i].

Neither of these assumptions is true.

What is the effect of these chemicals on hormones?

An FDA study in 2010 identified 1800 chemicals that disrupt one of three major hormone pathways (estrogen, androgen and thyroid)[ii]. And a European study found that 320 out of 575 chemicals screened showed evidence or potential evidence for endocrine disruption.[iii]

Some of these chemicals “mimic” hormones: they are able to attach to hormone receptors, which fool the body into over-responding to the stimulus (e.g., a growth hormone that results in increased muscle mass), or responding at inappropriate times (e.g., producing insulin when it is not needed). Other endocrine disrupting chemicals block the effects of a hormone from certain receptors (e.g. growth hormones required for normal development). Still others directly stimulate or inhibit the endocrine system and cause overproduction or underproduction of hormones (e.g. an over or underactive thyroid).

There seem to be critical periods of development when exposure can be more dangerous. Prenatal exposure can lead to lower birthweight and premature birth in babies. There is also evidence that babies whose mothers have been exposed to these chemicals are more likely to have intellectual disabilities and attention-deficit disorder, as well as behavior disorders and autism.

Exposure in adults has been associated with higher rates of obesity and type 2 diabetes. In men specifically, exposure to EDCs has been linked with male infertility, prostate cancer and low testosterone.

Because of the long timelines, it can be challenging to draw clear associations between EDCs and specific health indicators, which means they may be linked to other conditions and diseases we are currently unaware of.

Further complicating matters is that many known EDCs have since been replaced by others that have not been adequately tested[iv].

Which endocrine disrupting chemicals are the worst offenders and how can we avoid them[v]?

BPA: A hormone “imitator”. Try to avoid canned foods (the linings of which can contain BPA), paper receipts (which are coated with BPA), and plastics marked #7.

Dioxins: Affect sex hormones in both males and females. The food supply is widely contaminated with dioxins, especially meat, fish, milk, eggs and butter. Eating less animal protein and buying organic is the best way to avoid them.

Atrazine: Linked to prostate cancer. This has become a pervasive contaminant of drinking water, also used on crops. Buy organic produce and use a water filter that can remove atrazine.

Phthalates: Associated with low sperm count, obesity, diabetes and thyroid disruption. Prevalent in many plastic containers and children’s toys marked with #3. Many personal care products with “fragrance” on the label mean that they contain phthalates so it is important to read labels. 

Perchlorate: In produce and milk, affecting thyroid hormones and metabolism. Perchlorates are difficult to avoid, but a reverse osmosis filter and using iodized salt can be helpful.

Fire retardants: Very pervasive and longlasting, these imitate thyroid hormones. Use a vacuum cleaner with a HEPA air filter, and try to stay away from furniture with foam padding as well as padding underneath carpets.

Lead: A well known neurotoxin that also affects stress hormones. Dispose of old paint with care and drink filtered water, which can remove lead that leaches into the water from lead pipes.

Arsenic: A well known poison found in drinking water that also affects sugar and carbohydrate metabolism. Drink filtered water.

Mercury: Another toxin, found in higher concentrations in seafood. Try to buy sustainable seafood such as wild salmon.

Perfluorinated chemicals (PFCs) including PFOA: Found to be completely nonbiodegradable (i.e. they last forever), PFCs are associated with a host of hormone-related health conditions and are found in non-stick cookware, as well as furniture and carpets that claim to be stain- and water-resistant. Try to avoid all of these if possible.

Organophosphate pesticides: Still commonly and widely used despite their known effects on hormones such as testosterone and thyroid levels. The best way to avoid them is to buy organic produce.

Glycol ethers: Found in common solvents and cleaning products, these affect fertility and are also associated with allergies and asthma in children. Avoid cleaning products that contain 2-butoxyethanol (EGBE) and methoxydiglycol (DEGME).

This may seem like a long list, however, these are only the main EDCs; there are many more not covered here.

What else can I do?

The avoidance strategies just described are the best way you can protect yourself and your family from the harmful effects of EDCs. This is a blog about health and the endocrine system so I would normally leave it there. But as valuable as individual measures might be, they clearly do not resolve the problem of negative health effects caused by EDCs.  

The reason why EDCs remain so pervasive in our food, water, consumer products and our  environment, is because there is insufficient oversight and action taken to restrict their production and distribution.

So I urge you to, first, educate yourself further about EDCs and potential exposures for you and your family. The following are some helpful websites:

https://www.hormone.org/your-health-and-hormones/endocrine-disrupting-chemicals-edcs

https://www.endocrine.org/topics/edc

https://www.nrdc.org/stories/9-ways-avoid-hormone-disrupting-chemicals

https://www.ewg.org/consumer-guides/dirty-dozen-endocrine-disruptors

Second, advocate for: more research, more testing, more transparency and more oversight over EDCs. Here is a website to help you link up with others who are doing the same thing:

https://www.hormone.org/support-and-resources/advocate-for-hormone-health

Some immediate actions you can take:

1) If you or your family have been directly affected by EDCs, share your story.

2) Speak up at a local town hall.

3) Send a Letter to the Editor of your local (or other) newspaper.

4) Write to Congress and let them know your concerns about EDCs.

5) Visit your Representative. 

We should not have to take extraordinary measures to protect ourselves and our families from EDCs. Nor should we passively accept near-constant exposure to these chemicals as “normal”.

Let your voice be heard.

[i] Kahn, L, C Philippatt S Nakayama R Slama L Trasande (2020) “Endocrine-disrupting chemicals: implications for human health” Lancet Diabetes Endocrinology 8: 703–18

[ii] Ding D, L Xu L H Fang et al (2010) “The EDKB: an established knowledge base for endocrine disrupting chemicals” BMC Bioinformatics 11 (suppl 6): 5.

[iii] European Commission (2015) “Endocrine Disruptors” https://ec.europa.eu/environment/chemicals/endocrine/documents/index_en.htm#SubThemes5  

[iv] Kahn, L, C Philippatt S Nakayama R Slama L Trasande (2020) “Endocrine-disrupting chemicals: implications for human health” Lancet Diabetes Endocrinology 8: 703–18

[v] Much of the information in this section comes from KAB and EWG (2013) “Dirty Dozen List of Endocrine Disruptors” accessed from: https://www.ewg.org/consumer-guides/dirty-dozen-endocrine-disruptors