We live in a toxic world. Microplastics are being found in the fish we eat, pesticides are being applied indiscriminately, and our drinking water seems to be contaminated with an endless number of chemicals and heavy metals. Many of these toxins are known as endocrine-disrupting chemicals.
When most people think of toxins, however, the endocrine system may not be what they’re thinking of—but they should. From your libido to your appetite to your sleep patterns—the endocrine system controls other systems in your body through the language of hormones.
But this signaling system is delicate. For you to stay healthy, your glands need to release just the right amount of hormones. So what happens when something, such as an endocrine-disrupting chemical, throws off this balance? And should you be worried? Let’s find out.
What Are Endocrine-Disrupting Chemicals?
Endocrine-disrupting chemicals (EDCs) are natural or man-made chemicals that interfere with normal hormone processes. The trouble with EDCs is that many of them are found in products you may have in your home or in your food and water. It’s become almost impossible to avoid them.
Hormones play a crucial part in your health. They not only regulate sexual development during our teenage years, but they are also essential to a healthy immune system. In other words, balanced hormones help you thrive.
And that’s what makes the ubiquitousness of EDCs so concerning. The mechanisms through which EDCs work are:
- Mimicking hormones: Some EDCs mimic naturally-occurring hormones and trick the body into responding. This overstimulation can eventually lead to a decrease in sensitivity to the hormone.
- Blocking hormones: EDCs can bind to a hormone’s receptor on a cell and block natural hormones from binding. The normal signaling process fails to occur, and so the body cannot respond appropriately.
- Interfering with production and/or regulation of hormones: Other EDCs can affect how hormones are made, controlled, degraded, or stored in our bodies.
- Modifying the body’s sensitivity to hormones: Upon binding to hormone receptors, EDCs can alter the body’s response, creating one that’s either more powerful or less powerful than the original. EDCs may also create an entirely different response.
Simply put, by disrupting natural hormone processes, EDCs can affect the normal functions of your tissues and organs. Let’s take a more detailed look at the endocrine system and what it does.
What is the Endocrine System and What Does It Do?
The endocrine system is a collection of glands that produce and secrete hormones used by the body for a wide variety of functions. Think of hormones as the messengers that enter the bloodstream and travel throughout the body looking for their target cells. Over 50 hormones have been identified in the human body.
Some of the functions that these hormones regulate include:
- Blood sugar levels
- Development of the brain and central nervous system
- Growth and development
- Tissue function
- Sensory perception
Let’s take a look at the key parts of the endocrine system.
Hypothalamus: A small region in the brain that connects the endocrine and nervous systems by way of the pituitary gland. It is responsible for maintaining the body’s homeostasis by regulating the production of hormones from the pituitary gland.
Pituitary: This tiny organ found at the base of the brain is known as the “master gland” of the body for its role in producing hormones that direct certain processes in the body or stimulate other glands. It can also store some hormones. Some of the hormones produced by the pituitary gland are adrenocorticotropin, thyroid-stimulating hormone, follicle-stimulating hormone, and prolactin.
Pineal: The pineal gland is another small endocrine gland in the brain that produces melatonin.
Thyroid: The thyroid gland is a butterfly-shaped organ located in your neck and is responsible for producing hormones that regulate metabolism. Thyroid hormones regulate many vital body functions, a few of which include:
- Body weight maintenance
- Heart rate
- Muscle strength
- Menstrual cycles
- Body temperature
- Cholesterol levels
- Central and peripheral nervous systems
- Bowel movements
Parathyroid: The parathyroid glands consist of four tiny glands located behind the thyroid gland. These glands keep the body’s calcium levels under tight control by producing the parathyroid hormone. This regulation is essential to maintain proper functioning of the heart, kidneys, bones, and nervous system.
Adrenal: Best known for producing adrenaline, the “fight or flight” hormone, the adrenal glands are attached to the top of the kidneys and are made up of the adrenal cortex (the outer part) and the adrenal medulla (the inner part). The adrenal cortex produces some well-known hormones, such as cortisol.
Thymus: This small organ is located behind the breastbone and between your lungs. Although it is not active throughout the full lifetime, it helps the body produce the hormone thymosin and white blood cells called T lymphocytes that play vital roles in a child’s immune system.
Pancreas: Although it’s common to think that the pancreas is only involved in digestion, it also has an endocrine function. It secretes hormones directly into the bloodstream. Two main pancreatic hormones are insulin and glucagon, which help the body regulate blood sugar levels.
Gonads: The gonads are the sex glands in the body. In males, the testes make testosterone, which is responsible for the development of broad shoulders, growth of facial and body hair, growth of the penis, and increased muscle and bone mass. In females, the ovaries primarily produce estrogen and progesterone, which help develop breasts, widen the pelvis, enable greater fat distribution in the hips, thighs, and breasts, and regulate the menstrual cycle.
The “Dirty Dozen” and How You Can Avoid Them
There are nearly 8,000 man-made chemicals the U.S. Environmental Protection Agency considers to be produced in “significant amounts.” You may come into contact with many of these chemicals, including EDCs, every day.
The Environmental Working Group (EWG) released a list of the 12 worst offenders known as the “Dirty Dozen.” Let’s go over what they are and how you can avoid them.
1. Bisphenol A (BPA): This should come as no surprise. You may have noticed more and more companies turning away from this popular ingredient used to make certain plastics, such as plastic packaging, toys, healthcare equipment, and kitchenware. Simply touching thermally-printed cash register receipts increases your exposure to BPA. The EWG reports that an estimated 93% of Americans have BPA in their bodies.
The dangers of BPA to your health have been made clear by decades of research. It mimics the sex hormone estrogen, tricking your body into thinking it’s the real deal. Because it interacts with estrogen receptors and signaling pathways that depend on them, BPA has been linked to several health problems, including:
- Infertility (female and male)
- Early puberty
- Breast cancer
- Prostate cancer
- Polycystic ovary syndrome (PCOS)
- Heart disease
How do you avoid it? Avoid canned food as much as possible, or research companies that don’t use BPA and similar chemicals in their products. Choose fresh food whenever possible. Say no to thermally-printed cash register receipts. Avoid polycarbonate plastics, which are usually marked with the recycling code #7 or with “PC.” The EWG recommends plastics with codes #1, #2, and #4 since they do not contain BPA. Better yet, use stainless steel bottles instead of plastic water bottles. Avoid microwaving plastic containers.
For more tips, check out EWG’s page on how to avoid BPA exposure.
2. Dioxin: Dioxins are some of the most toxic chemicals known to man. The term “dioxin” is used to describe chemicals that are formed as unintentional byproducts of industrial processes that burn chlorine-based chemical compounds with hydrocarbons.
The EPA and the World Health Organization (WHO) have confirmed that dioxins are human carcinogens. But what makes dioxins incredibly harmful to human health is that there doesn’t appear to be a “safe” level of exposure. In a 2003 report, the EPA concluded that there is no threshold below which dioxins will not cause cancer.
Dioxins are also linked to severe birth defects, miscarriages, decreased fertility, reduced sperm counts, learning disabilities, lung and skin problems, endometriosis, diabetes, and many other health problems. To make matters worse, dioxins are persistent—in your body and in the environment.
According to the Center for Health, Environment and Justice (CHEJ), between 90% and 98% of dioxin that Americans are exposed to come from foods, mostly meat, fish, and dairy products. Foods that contain the highest levels of dioxin include:
- Ground beef
- Soft blue cheese
- Beef rib steak
- Lamb sirloin
- Heavy cream
- Soft cream cheese
- American cheese sticks
- Pork chops
- Cottage cheese
For a detailed report on dioxins and their effects on human health, read The American People’s Dioxin Report.
How do you avoid it? It’s difficult to avoid dioxins. The best recommendation is to reduce your exposure as much as possible by eating fewer animal products since they are more likely to be contaminated.
3. Atrazine: Humans aren’t the only ones affected by toxic chemicals in the environment. In the case of the popular herbicide atrazine, male frogs can become completely feminized as adults—and produce viable eggs. Animals exposed to atrazine have also been shown to suffer from depressed testosterone, decreased fertility, suppressed mating behavior, prostate inflammation, breast tumors, and delayed puberty.
Atrazine is the most commonly detected pesticide on the ground and in surface water. Just about 80 million pounds of this EDC is used every year in the United States alone, and it can be transported more than 1,000 km from the place of application by rain. This means that remote areas are not safe from atrazine.
How do you avoid it: Buy organic whenever possible and get a water filter certified to remove atrazine. Check out EWG’s Water Filter Guide to find the filter that works best for you.
4. Phthalates: Phthalates, often called plasticizers, are a group of chemicals used to soften plastics and make them harder to break. And once again, it’s another type of EDC very commonly found in our homes. Exposure to phthalates can come from:
- Cosmetics and fragrances
- Personal care products
- Shower curtains
- Plastic toys
- Modeling clay
- Vinyl flooring
- Cleaning products
- Food packaging and wraps
- Window blinds
- Medical devices
As you can see, phthalates are lurking just about everywhere. But generally, your body can metabolize and excrete phthalates quickly. So why are they dangerous? The answer may lie in the fact that our exposure to phthalates occurs on a persistent, daily basis. Because phthalates can be ingested, inhaled, and absorbed through the skin, the observed adverse effects may be due to cumulative intakes that exceed the body’s tolerated levels.
The health hazards attributed to phthalates seem endless. They interfere with the production of testosterone, which can have irreversible effects on male reproduction. Other effects include:
- Infertility (male and female)
- Decreased sperm count
- Undescended testes
- Malformed penis and urethra
- Preterm birth
- Low birthweight
- Worsening allergy and asthma symptoms
- Type 2 diabetes
- Skeletal abnormalities
How do you avoid it? Like many other types of EDCs, avoiding phthalates may be difficult, but there are steps you can take to reduce your exposure. Avoid plastic food containers, plastic children’s toys, and plastics with recycling label #3. Also avoid personal care products that simply say “fragrance” as an ingredient, since this term can mean hidden phthalates.
5. Perchlorate: Rocket launches are truly amazing, but drinking water contaminated with rocket fuel? Not so much. But perchlorate, an oxidizer for fireworks, munitions, and rocket fuel, has been found in well water and drinking water throughout the United States. It has also been detected in soil and crops—even in organically grown ones. Although the presence of perchlorate in drinking water was discovered in the 1950s, it was only recently that scientists started examining its toxicological properties.
At high enough concentrations, perchlorate blocks the uptake of iodine by the thyroid gland, disrupting the normal functions of the thyroid. Perchlorate can also have the following effects:
- Loss of body weight
- Reproductive problems
- Likely human carcinogen
- Developmental delays
How do you avoid it? If you live near a location where perchlorates were found to be present in drinking water, the EWG recommends installing a reverse osmosis filter. Also, make sure you are getting enough iodine.
6. Flame retardants: As the name suggests, flame retardants are chemicals that are added to materials, such as mattresses and carpets, to provide fire safety. Although many flame retardants are no longer produced, like many EDCs, they are persistent in the environment. This means that they can stick around for years and build up in the bodies of people and animals around the world—including polar bears.
Flame retardants have been associated with adverse health effects, such as:
- Endocrine and thyroid disruption
- Reproductive toxicity
- Impaired neurological development
- Lower birth weight
- Behavior changes
- Early onset puberty
Many people are exposed to flame retardants when the chemicals leach from products into dust and air. The dust settles on hands and food. Children, firefighters, and workers at sites handling products with flame retardants are vulnerable to their effects.
How do you avoid it? It’s nearly impossible to avoid flame retardants. A few recommendations for reducing exposure to them include keeping dust levels down in your home, cleaning with a HEPA filter vacuum, practicing good hand hygiene, having a good ventilation system in your home, and purchasing baby products and furniture filled with cotton, polyester, or wool, instead of polyurethane foam.
7. Lead: With the Flint water crisis in recent years, lead contamination in drinking water has burst into the spotlight. Lead is a toxic substance that accumulates in multiple body systems, such as the brain, liver, kidney, and bones and is particularly harmful to children. Lead particles can also be inhaled when materials containing lead are burned, for example, during stripping of leaded paint or using leaded gasoline.
Lead poisoning has been linked to a staggering number of health issues, including:
- Lowered IQ
- Brain damage
- Premature birth
- Behavioral disorders
- Renal impairment
- Reproductive organ toxicity
Many of the damages caused by lead poisoning are believed to be irreversible.
How do you avoid it? Old, lead-based paint in homes is a major source of lead. Vacuum and dust regularly to prevent lead particles from accumulating or consult a professional for safe removal. Address any water damage to your home quickly. You may also want to test your water for lead and filter accordingly, if present. Finally, if you’ve been looking for another reason to eat better, research has shown that a healthy, balanced diet can reduce the absorption of lead.
8. Arsenic: When you think of arsenic, a murder mystery might come to mind. But arsenic poisoning isn’t a fictional story anymore—it’s in your food and water.
There is some confusion when it comes to arsenic, and that’s because there are two forms, organic and inorganic. Organic arsenic is a non-toxic compound found naturally in food, such as fish and algae. It raises arsenic levels in the blood but is quickly excreted through urine.
On the other hand, inorganic arsenic is extremely toxic, inactivating up to 200 enzymes, many of which are involved in DNA replication and repair as well as cellular energy pathways. It can enter the food chain from insecticides or pesticides that contain arsenic or from soil and water contamination.
The most common clinical manifestations of acute arsenic poisoning include:
- Colicky abdominal pain
- Excessive salivation
- Acute psychosis
- Skin rash
- Toxic cardiomyopathy
Long-term, chronic arsenic poisoning can lead to disease involving multiple systems, and clinical features vary between individuals. At this time, it’s unclear what factors determine particular clinical symptoms. Therefore, individuals with chronic arsenic toxicity can display an extensive range of symptoms, a few of which include:
- Hyperpigmentation of skin
- Skin cancer
- Nerve damage
- Enlargement of liver
- Heart disease
- Blackfoot disease
- Behavioral changes
- Memory loss
- Cognitive impairment
- Cancer (bladder, kidney, urethral, prostate, etc.)
- Lung disease
How do you avoid it? Having safe drinking water is a priority. Studies have reported that iron-treated natural materials, such as iron-treated activated carbon, were effective at absorbing arsenic from water.
9. Mercury: If you eat seafood, you may have been warned about mercury poisoning. While all humans are exposed to some level of mercury, some are exposed to the toxin at much higher levels than most, particularly populations that rely on fishing as a main source of food. A report from the International POPs Elimination Network and Biodiversity Research Institute found that 84% of the fish sampled from around the world contained mercury concentrations that exceed the U.S. EPA consumption guidelines.
The various forms of mercury—elemental, inorganic, and organic—have differing levels of toxicity and ability to accumulate in the body. Elemental and organic mercury are toxic to your nervous system and can also affect the digestive and immune systems. The metal may also lead to:
- Disruption of women’s menstrual cycle and ovulation
- Memory loss
- Gingivitis and excessive salivation
- Behavior and personality changes
- Kidney toxicity
- Thyroid dysfunction
Mercury exposure can also be fatal.
How do you avoid it? If you want to continue eating seafood, wild Alaskan salmon, anchovies, catfish, freshwater trout, ocean perch, pollock, and whitefish are some good choices.
10. Perfluorinated chemicals (PFCs): Non-stick cookware is popular because it makes dishwashing so much easier, but at what cost? PFCs, the compounds used to make stain-, grease-, and water-repellent items, take several years to break down in your body. Unlike most persistent chemicals, PFCs bind to proteins instead of fats, and they can accumulate in the blood serum, kidney, and liver.
It has been estimated that 99% to 100% of Americans have PFCs in their bodies. In one study, nearly 100% of all umbilical cord blood samples from newborns in Baltimore tested positive for the chemicals. This is particularly worrisome because it indicates that PFCs can cross the placenta and possibly affect the fetus, the most sensitive stage of human development.
PFC exposure has been linked to:
- Reduced human fertility
- Lower birth weight
- Higher odds of ADHD
- Irregular menstrual cycles
- Lower sperm count
- Increased cholesterol
- Thyroid disruption
- Increased severity of allergies
How do you avoid it? Practice good hand hygiene to reduce ingestion of PFCs from contact with consumer products and dust. Avoid consuming fast foods and packaged foods, fluorinated stain repellent treatments, stain or dirt-repellent clothing, and personal care products with fluoro or perfluoro on the ingredient list. Dust with a wet cloth and use a vacuum cleaner with a HEPA filter. Also, avoid non-stick cookware and microwave popcorn.
11. Organophosphate pesticides: Organophosphates are pesticides designed to attack the nervous system of insects. That’s why they are so effective. But there’s a downside—they’re also extremely toxic to humans.
Upon entering the body, organophosphates inhibit an enzyme called cholinesterase, which breaks down acetylcholine, a neurotransmitter that the nervous system uses to activate muscles. When cholinesterase cannot function, acetylcholine builds up in the nerves. In high enough concentrations, this results in an overactivation of nerves and eventually death due to the inability to breathe.
Although there are laws preventing high-level exposure to organophosphates in the U.S., several studies have suggested that chronic low-level exposure can lead to serious health consequences. Dangers of chronic exposure to organophosphates include:
- Increased risk of ADHD
- Eye pain and blurred vision
- Birth defects
- Childhood brain tumors
- Lowered IQ
- Delays in reproductive development
How do you avoid it? Try to purchase local, organic produce whenever possible.
12. Glycol ethers: Glycol ethers are a group of organic solvents used in various cleaning products, brake fluid, paints, and cosmetics. Acute, high-level exposure to glycol ethers can result in narcosis, pulmonary edema, and severe liver and kidney damage. On the other hand, acute, low-level exposures cause conjunctivitis, upper respiratory tract irritation, headache, nausea, and temporary corneal clouding.
Chronic exposure to the chemical can result in the following:
Animal studies have shown that glycol ethers can also cause bone marrow depression, testicular atrophy, developmental toxicity, and immunotoxicity. The U.S. EPA also does not classify glycol ethers for carcinogenicity.
How do you avoid it? There are many non-toxic cleaners available on the market today. Avoid products that have ingredients like 2-butoxyethanol (EGBE) and methoxydiglycol (DEGME).
When The Dose Does NOT Make the Poison
In the 16th century, Swiss physician and chemist Paracelsus said, “All substances are poisons; there is none which is not a poison. The right dose differentiates a poison from a remedy.”
In other words, the dose makes the poison.
This basic adage of toxicology has become the basis for public health standards across the globe, which specify maximum limits on concentrations of contaminants allowed in food, drinking water, and the environment.
And it makes logical sense—usually. But endocrine disruptors are disobeying the law, forcing scientists to think differently.
The “Low Dose” Hypothesis
In the 1990s, scientists proposed the “low dose” hypothesis, which suggests EDCs cause significant health effects at extremely low doses as compared to those observed at higher doses.
The term low-dose effects are defined by the U.S. EPA and the National Toxicology Program (NTP) as “biologic changes that occur in the range of human exposures or at doses lower than those typically used in the standard testing paradigm of the U.S. EPA for evaluating reproductive and developmental toxicity.”
There are other definitions to consider:
- A dose below the lowest dose at which a biological change for a specific chemical has been measured in the past (i.e., any dose below the lowest observed effect level or lowest observed adverse effect level)
- The dose administered to an animal that produces blood concentrations of that chemical in the range of what has been measured in the general human population (i.e., environmentally relevant dose)
It’s no longer a question of whether EDCs affect disease or not. Decades of epidemiological studies show that environmental exposures to EDCs are associated with human diseases.
Hormones circulate in extremely small amounts—parts-per-trillion and parts-per-billion concentrations. While that means hormones are highly potent and effective, it also means that your endocrine system is delicate. Tiny alterations in their concentrations or activities, particularly during fetal development and in infants, could have significant, lasting effects.
For that reason, proponents of the hypothesis argue that because EDCs can mimic hormones, they can cause health issues even at extremely low levels.
But not everyone is open to accepting this theory. Opponents of the “low dose” hypothesis say that there is no broad consensus on the definition of “low dose”—without a clear definition, the hypothesis is not scientifically testable, and thus cannot be validated. Some also accuse proponents of the hypothesis of inappropriate, selective citation of studies and of assuming that any statistically significant association means causation of an adverse effect.
Should You Be Worried About Low-Dose Endocrine Disruptors?
The truth is, there isn’t sufficient evidence for scientists to decisively link exposure to a specific EDC to an individual’s health problems. Given the many variables that contribute to our health—age, genetics, diet, environment, etc.—it is difficult for many researchers to accept a theory that extremely low doses of EDCs can produce ill health effects that are not predicted by higher doses.
Still, there is enough evidence to be concerned, especially for young children and individuals who have compromised immune systems. More research will always be necessary, and we may never fully understand the countless ways in which each EDC affects our health.
So what can you do? Where science lacks full certainty, it’s important to take precautions. Follow the tips I listed above to reduce your exposure to EDCs as much as possible. You can find additional tips in We Can No Longer Ignore Glyphosate.
I’ve put together a thorough guideline with more detail to help you through the process of reducing your toxin exposure. You can find that here: Reduce Your Daily Toxin Exposure.