Endocrine Disruptors: What Are They and How Do They Affect Us?

Endocrine disruptors are chemicals that can interfere with the endocrine system and affect our health.

[This text was originally written by Alicia Abellán in 2020 and has been updated by researcher Nuria Güil in October 2023].

What are endocrine disruptors?

Hormones are signalling molecules responsible for communication between the cells in different organs throughout our bodies. These molecules play an essential role in numerous systems throughout the body. Endocrine disruptors (EDCs) are chemicals that can mimic the action of our natural hormones.They can also block hormone receptors in cells, preventing normal hormone action. This causes disruption (alteration) of the endocrine system.

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Where are they found?

The list of endocrine disruptors is very long. More than a thousand chemical substances with this disruptive capacity have been identified. Depending on their molecular structure and source of exposure, we find the following main groups:

• Heavy metals such as mercury, cadmium, lead and arsenic. They are found in the environment and accumulate in many of the animals we eat, especially predatory fish such as tuna, swordfish or shark, as well as molluscs and crustaceans.
• Pesticides. Those with a toxic legacy, such as DDT, which although banned in the 1970s, persists in the ecosystem and accumulates in animal fat, from where it enters the human food chain. And current pesticides, such as the widely used organophosphate insecticides.
• Per- and polyfluoroalkyl substances or PFAS, also known as "everlasting chemicals" due to their long persistence in the environment (up to thousands of years). Due to their physicochemical properties, PFASs are highly water and oil repellent and can withstand extreme temperatures. This is why they are found in food packaging, non-stick pans and pots, cleaning products, and have recently been found in supposedly biodegradable paper and bamboo straws.
• Flame retardants. These are substances added during the manufacture of furniture, plastics, textiles or electronic equipment to make them less flammable. These chemicals can migrate into the environment and accumulate in dust and indoor air.
• Phenols. These include bisphenols such as the famous bisphenol A (BPA), which is widely used in the lining of metal food and drink cans, plastic bottles and Tupperware. There are also parabens, which are found in countless everyday cosmetic products, and triclosan, which is used in personal care products such as toothpaste, hydro-alcoholic gels and deodorants. Finally, benzophenones are used as UV filters in most sunscreens and make-up.
• Phthalates are widely used in cosmetics, perfumes, paints and in the manufacture of plastic packaging. Heating food containers promotes the migration of phthalates into food, and eating out, especially fast food, has been shown to increase phthalate levels in the body.

In short, endocrine disruptors are ubiquitous and we are constantly being exposed to them. Large population studies have found endocrine disruptors in the biological samples from over 95% of study participants.

Large population studies have found endocrine disruptors in the biological samples from over 95% of study participants

How are we exposed to endocrine disruptors?

Although we may not realise it, endocrine disruptors are all around us and we are constantly being exposed to low doses of these chemicals. They enter our bodies through the food we eat, through the air we breathe and through direct contact with our skin. They can reach the foetus by crossing the placental barrier and have also been found in breast milk. Substances known as persistent endocrine disruptors—a category that includes certain pesticides—can remain in the body for up to ten years. Non-persistent endocrine disruptors such as parabens and bisphenols remain in the body for anywhere from a few hours to several days.

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How do endocrine disruptors affect our health?

Endocrine disruptors can interfere with the proper functioning of the endocrine system and other essential bodily systems and functions. Depending on their structure, they can have adverse effects on respiratory, cardiovascular, metabolic, cognitive and reproductive health, as well as on childhood development from before birth to adulthood.

We do not yet fully understand the health effects of most of these compounds. Animal and human studies have found associations between endocrine disruptors and increased risk of certain cancers, obesity, infertility, diabetes, metabolic syndrome, asthma and neurodevelopmental disorders. The resulting economic impact in the European Union alone is estimated to be more than €160 billion per year.

The resulting economic impact in the European Union alone is estimated to be more than €160 billion per year.

Are some populations more vulnerable than others?

Since endocrine disruptors can cross the placental barrier and pass into breast milk, foetuses and nursing infants can be exposed to these substances. During these crucial stages of development, the body is especially vulnerable to the effects of such environmental exposures. Alterations at this stage of life can disrupt the correct development of the body and have long-term health effects.

Main challenges in studying the health effects of endocrine disruptors

A key characteristic of endocrine disruptors is that their effects do not always follow typical dose-response patterns: higher doses do not always result in greater effects. In other words, the dose-response curve for the effects of endocrine disruptors is non-monotonic.

In some studies, greater effects have been observed at low doses than at higher doses. To complicate the matter even further, in our everyday lives, we are not exposed to a single endocrine disruptor in isolation but to all sorts of pollutants simultaneously. We still do not fully understand how these substances interact in our bodies and the overall health effects of these exposures.

Lack of consensus on regulation

There is currently no global consensus on how endocrine disruptors should be regulated. Given the peculiar nature of the toxicity of endocrine disruptors and the differences between the properties of different substances, it is very difficult to establish safe exposure thresholds.

There is currently no global consensus on how endocrine disruptors should be regulated. Given their peculiar nature of the toxicity and the differences between the properties of different substances, it is very difficult to establish safe exposure thresholds

The regulation of endocrine disruptors in Europe has been a subject of considerable debate in recent years despite industry pressure. The European Commission has recognised endocrine disruptors as potentially hazardous to health and has ordered an exhaustive study with the aim of improving their regulation in the near future to minimise human and environmental exposures.

What can we do?

First of all, there is no cause for alarm. Our health does not depend solely on exposure to endocrine disruptors. Concentrate on maintaining a healthy lifestyle, eating a balanced diet, getting physical exercise and avoiding harmful habits such as smoking.

There is no cause for alarm. Our health does not depend solely on exposure to endocrine disruptors. Concentrate on maintaining a healthy lifestyle

As a consumer, try to be more aware of what you buy and use. Small changes in everyday habits can reduce your exposure to endocrine disruptors. For example:

• Heat up your food in a glass or ceramic recipient rather than a plastic container.
• Ventilate and thoroughly clean the interior from dust.
• Use non-stick ceramic, cast iron or stainless steel pans.
• Use stainless-steel or glass bottles instead than plastic ones.
• Avoid cosmetics that contain endocrine disruptors (prefer paraben, benzophenone, triclosan, phthalate free).
• Reduce your intake of processed or canned foods.
• Limit the consumption of animal products.
• Buy locally grown organic fruits and vegetables, and wash them thoroughly.

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