Endocrine Disruptors



Pollutants that, even at low doses, have major effects on health.

According to the WHO, an endocrine disruptor is "a substance or mixture of substances, which alters the functions of the endocrine system and thereby induces adverse effects in an intact organism, in its offspring or in (sub)populations".

Hormones and the endocrine system

 



There are two means of communication in the body: the nervous system and the endocrine system.

Hormones are the body's chemical messengers that control multiple functions including growthreproductionsexual functionsleephungermood and metabolism.

Hormones are produced by the endocrine glands:

  •     Pituitary gland
  •     Hypothalamus
  •     Epiphysis
  •     Thyroid
  •     Parathyroid
  •     Thymus
  •     Adrenals
  •     Pancreas
  •     Ovaries
  •     Testicles

The pituitary gland and the hypothalamus act as conductors of the endocrine system by controlling and regulating (production/removal) hormone levels in the blood.

What are the mechanisms of action of endocrine disruptors?

Hormones are present in very low concentrations, in the order of a few nanograms per litre of blood (1 g = 1,000,000,000 ng, part per billion ppb).

Hormone receptors in cells are extremely sensitive and specific. For this reason, endocrine disruptors are able to interact with the hormonal system from very low doses of exposure.


"For endocrine disruptors it is not the dose that makes the poison but the mere presence of traces"

Endocrine disruptors generally have "non-monotonic" relationships between dose and health effects.
This means that very low doses can have much greater effects than those observed for higher doses.


 



 

The main mechanisms of action of endocrine disruptors identified to date concern the controlproduction and distribution of hormones in the body:

  •     Mimicry of natural hormones: Direct action on specific cellular receptors for hormones. Mimicry of natural hormones: Direct action on specific cellular receptors for hormones, thus simulating the action of the natural hormone on the cells at the wrong time and with an excessive response.
  •     Competition with the natural hormone: Blocking the specific cellular receptors of the hormones. Thus preventing the action of the natural hormone.
  •     Binding to blood proteins: Altering the amounts of active natural hormones in the bloodstream. In the blood, natural hormones are either free and active or bound to blood proteins and inactive. Protein-bound hormones constitute a reserve available for rapid hormonal action.
  •     Action on metabolism: Modifying the regulation (synthesis and elimination) of natural hormones.

This list is not exhaustive as the study of the mechanisms of action of endocrine disruptors is very recent and there is still much to be discovered on this public health issue.

What are the main known health effects of endocrine disruptors?

The period of exposure to endocrine disruptors plays a crucial role. In particular during :

  •     The trimester before conception
  •     The 9 months of pregnancy (in-utero exposure)
  •     The first 2 years of life
  •     Puberty

Endocrine disruptors can affect the body long after exposure.

The main pathologies associated with endocrine disruptors are

  •     Early puberty (breast development and menstruation).
  •     Disorders of reproduction, fertility and fertility (testosterone synthesis, spermatogenesis, egg maturation).
  •     Growth and development disorders.
  •     Genital malformations (hypospadias, micropenis).
  •     Cancers, including hormone-dependent cancers (testicles, ovaries, breasts, thyroid, pancreas, prostate, etc.) and brain tumours (pituitary and hypothalamus).
  •     Impaired functioning of the endocrine glands.
  •     Behavioural disorders (hyperactivity).
  •     Sensory disorders.
  •     Obesity.
  •     Disturbance in the metabolism of cholesterol into steroid hormones (testosterone, estradiol, cortisol...).
  •     Immune disorders (weakened immune defences against viruses and bacteria).
  •  

How to protect yourself from endocrine disruptors?

The best way to protect yourself from the effects of disruptors is to limit your exposure as much as possible.

EXPOZOM proposes to search the body for substances that are known or suspected to be endocrine disruptors.

Testing for the presence of endocrine disruptors in the body is a reliable way to :

  •  Identify the substances to which the body is exposed
  •  Identify the substances to which the body is exposed; - Determine their origins in order to act to reduce exposure by eliminating them

The effect of mixtures of several endocrine disruptors is often much more harmful than the sum of their individual effects. It is therefore recommended to look for as wide a range of substances as possible.

A list of priority endocrine disruptors has been developed based on information obtained from national (ANSES, US EPA, HEALTH CANADA), international (WHO, ECHA) and independent (TEDX) health authorities.

In our daily environment, the main endocrine disruptors are

  •     Plastic additives such as phthalates and bisphenols, including bisphenol-A
  •     Additives in household products such as alkylphenols
  •     Pesticides (DDT, chlorpyrifos, atrazine, 2,4-D, glyphosate)
  •     Chlorinated (PCB) and brominated (PBDE) flame retardants
  •     Food additives such as BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene)
  •     Heavy metals such as cadmium, mercury and lead
  •     Perfluorinated Teflon-type non-stick additives (PFOA, PFOS)
  •     Preservatives (parabens) and antibacterial agents (triclosan)
  •     Hormonal contraceptives
  •     Plant sterols