Context - The endocrine system is composed of various glands and organs in the body that regulate many aspects of the body. It can be, and often is, affected by external factors, such as chemicals. When these chemicals cause health problems, they are referred to as 'endocrine disruptors'.
The way they interact with the body, often in very small amounts, makes their risk evaluation difficult.
Are current methods adequate? www.efsa.europa.eu/efsajournal
What are endocrine disruptors?
Endocrine disruptors are substances,
either natural or of human synthetic origin, that have an effect considered to
be negative on the endocrine system.
The endocrine system is composed of
various glands and organs in the body that play various roles in maintaining the
good physiological status of the body. It
includes for instance the adrenal glands,
the thyroid, the testes and ovaries. The
endocrine system influences almost every cell, organ, and function of an
It regulates, by the use of numerous
molecular messengers known as
hormones, various vital functions
such as metabolism, growth and
development, tissue function, or
mood, from conception through adulthood and into old age. This includes for
example the development of the brain and nervous
system, the growth and function of the reproductive system, or the
regulation of blood sugar level.
The endocrine system can be, and often
is, affected by external factors, such as chemicals. There are many synthetic or
natural substances that can interact with the endocrine system, and if the
interaction creates problems, the substance is considered to be an ‘endocrine
What kind of substances can interfere with the endocrine system?
Many substances released into the environment through human activity can
potentially interfere with the endocrine or
hormonal systems of animals and humans.
Such endocrine active substances (EASs) include synthetic drugs,
pesticides, compounds used in
industry and in consumer products, industrial by-products and
pollutants, including some
There is also a large number of substances of natural origin that can interact
with the endocrine system. These substances
occur in plants consumed as food or feed, and also as
contaminants from fungi that may be
present in food and feed.
This is because the endocrine system
functions, like many other systems in the body, in a ‘lock and key’ model, where
a signalling molecule – in this case an
hormone – is ‘recognized' by a
cellular structure named "a receptor " by
fitting in it. For many hormones, these
receptors are at the surface of the
cells, and the biochemical message they
carry tells the cell to do something specific, from growing to producing a
specific compound, or to any of a myriad of
functions a cell can accomplish. Any compound that either fits the « lock »
instead of the hormone or prevents the ‘key’ from entering the lock e.g. by
masking it, can potentially disturb the system by sending a false signal, or by
preventing a signal from reaching its intended target.
Are there specific issues with the evaluation of endocrine disruptors?
There are a number of key issues with the evaluation of potential
- There is no clear scientific definition of what a ‘problem’is, when it
comes to the endocrine system, and as such, a standard evaluation of chemicals
is difficult. This is in part due to the fact that there are so many different
ways that chemicals can interact with the endocrine system.
- The concentrations of any substance that would have an endocrine effect
can be very low, sometimes even lower that the detection limit of standard
measuring methods. This makes it very difficult to evaluate a cause and effect
relationship, for instance.
- It is difficult to define below which concentration endocrine disruptors
cause no problem.
- There is a lack of standard evaluation methods for many of the numerous
ways that endocrine disruptors can interact with an organism.
The opinion of the committee is thus that for their
risk assessment, EDs can be treated
like most other substances of concern for human health and the environment. But,
it adds that the level of concern is not determined exclusively by risk
assessment but also by protection goals set by the
These are highlights of the report: “The scientiﬁc criteria for identiﬁcation of endocrine disruptors and appropriateness of existing test methods for assessing effects mediated by these substances on human health and the environment. ”, a report produced by the European Food Safety Agency.