[This article has been originally published in Catalan in 'Espai Salut' newsletter of Diputació de Barcelona]

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 are chemicals that can mimic hormones, derailing these systems and giving rise to negative health effects.

Endocrine disruptors are chemicals that can mimic hormones, derailing these systems and giving rise to negative health effects

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. The list includes pesticides, phthalates, parabens, bisphenols, triclosan, benzophenone, flame retardants and many more. And these chemicals are found in many everyday household products. For example, phthalates are found in toys, perfumes and cosmetics; parabens in cosmetics and food additives; bisphenols in plastic bottles, plastic food-storage containers, cans and cash-register receipts; and flame retardants in electronics and furniture.

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 them?

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.

How do they 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, asthma and neurodevelopmental disorders.

For example, the authors of animal studies report an association between exposure to bisphenol A and increased risk of obesity, diabetes, hyperactivity disorders, breast cancer and prostate cancer. Notably, some studies have found these effects at doses lower than the current safety threshold.

The authors of animal studies report an association between exposure to bisphenol A and increased risk of obesity, diabetes, hyperactivity disorders, breast cancer and prostate cancer

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. 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; use stainless-steel or glass bottles instead than plastic ones; avoid cosmetics that contain endocrine disruptors; reduce your intake of processed or canned foods; and buy locally grown organic fruits and vegetables.