Endocrine disruptors in a nutshell

To reduce our exposure to endocrine disruptors (ED), we need to know what these substances are, how they act, where they are found, and how they can enter our body or the environment.

What role is played by hormones and the endocrine system?
What are endocrine disruptors and how do they act?
Where are endocrine disruptors found?
Hazard doesn’t necessarily mean risk

What role is played by hormones and the endocrine system?

In humans and animals, hormones are responsible for controlling numerous biological processes and functions, such as body temperature, blood pressure, growth and reproduction.

Hormones are messengers that communicate with and can thus transmit information to cells. They are produced by various organs (e.g. the thyroid gland, sex organs, or pancreas) and are transported to target organs throughout the body via the bloodstream.

Having reached the cells of the target organ, the hormone acts like a key inserted in a lock to open a door:

It binds to the appropriate receptor
The binding of the hormone to the receptor triggers a signal
The signal elicits a specific cellular response

This «communication system» is known as the hormonal or endocrine system.

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What are endocrine disruptors and how do they act?

As the name suggests, endocrine disruptors interfere with the normal functioning of hormones by mimicking, blocking, or modifying their action; this may affect the organs whose activity is regulated by the hormones concerned.

For example, an endocrine disruptor may bind to a receptor, displacing the hormone. The resultant (inappropriate) cellular response may affect the function of the organ concerned.

The diagram is divided into three parts: on the left, the normal state is described, whereby the hormones dock to the receptors and thus send signals to the brain. The centre shows how certain endocrine disruptors imitate hormones, dock to the receptors and thus send faulty signals. On the right, it is shown how certain endocrine disruptors block the receptors, prevent the hormones from docking and therefore no signals are sent. — Possible mechanisms of action of endocrine disruptors

However, not all substances that influence the hormonal system are endocrine disruptors. A substance is only considered to be an endocrine disruptor if its action on the hormonal system produces harmful effects for the organism or its offspring.

Endocrine disruptors affect different hormones and thus different processes and functions, such as the circulatory, nervous or respiratory system, or reproduction, growth, behaviour and sleep. A slight change in hormonal balance induced by endocrine disruptors can produce different effects on these various functions.

It is interesting to note that substances with a similar chemical structure will not always cause the same effects. So even if a substance is recognised as an endocrine disruptor, this does not mean that all the substances in the same family will also be identified as such.

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Where are endocrine disruptors found?

Endocrine disruptors may be naturally occurring or synthetic substances. They are found almost everywhere. They may be present, for example, in

toys,
furniture,
packaging,
clothing,
cleaning and care products, or even in
plants such as soya or clover.

The issue of endocrine disruptors thus concerns sectors such as health, consumer protection, the environment, occupational health, food safety and agriculture.

Diet is one of the main sources of exposure to endocrine disruptors. These substances may be present in foodstuffs, either as natural constituents of plants (e.g. soya) or as a result of environmental contamination (e.g. pesticide residues).

However, endocrine disruptors can also be found in food as a result of contamination during packaging or preparation, since they may be present, for example, in containers or kitchen utensils. They may thus be found directly or indirectly in our food and thus in our body.

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Hazard doesn’t necessarily mean risk

The picture on the left shows a person standing next to a green and yellow snake and is frightened because the snake is slithering towards them. The snake represents a danger to the person. On the right of the picture, the same person is standing in front of a pane of glass behind which the snake is sitting. Here the snake poses no danger to the person as it is in a terrarium. This reduces the risk to the person. — Difference between hazard and risk

It is important to distinguish between a hazard and a risk. For example, a poisonous snake and a lion are both dangerous animals, but there is no risk for people visiting a zoo, as the animals are behind a window or in a pen.

The same principle applies to chemicals: even if a substance is classified as hazardous, this does not mean that it poses a risk to health. Exposure – i.e. contact with the substance – needs to be taken into account. If the contact with a substance is limited, the risk of harmful effects is consequently reduced.

Thus, a hazardous substance contained in a product is not necessarily harmful for the consumer. For example, descaling products are corrosive, and so they can be harmful to health if they come into contact with skin or are swallowed. However, when they are used properly to descale a coffee maker that is subsequently rinsed, there is no risk for the consumer.

A hazardous chemical substance may therefore be authorised for use in articles of daily use. If the article is correctly used, there is no contact with the consumer – no exposure – and the risk is thus limited.

Accordingly, chemical substances identified as endocrine disruptors continue to be used, as they endow products and materials with a variety of useful properties – such as resistance, durability, flexibility or antibacterial properties – without however posing a risk to consumers.

Numerous regulatory measures have been adopted to reduce overall exposure, and thus the risks posed by endocrine disruptors to human health and the environment (see the section on «Regulatory measures and legislation»).