How do endocrine disruptors work ?

What are endocrine disruptors ?

The thyroid is a tiny gland that secretes hormones essential to the activity of most of our cells.

It is extremely sensitive to our living conditions: stress, a change in diet or even long-term physical exertion can disrupt its functioning and efficiency.
But so canexposure to endocrine disruptors, chemical compounds that seem to have accumulated in our tissues over the last few decades…

Yet even the slightest thyroid disorder can disrupt most of our body’s key functions: nervous, endocrine, digestive and cardiovascular systems, immunity, sleep, weight, fertility, mental balance… our entire quality of life is affected!

An estimated 6 million French people suffer from thyroid disorders today.

The term “endocrine disruptors” was coined by Theo Colborn in 1991.

“An endocrine disruptor (also called “hormone decoy”, “xenohormone”.) is a compound chemical molecule or agent, xenobiotic with hormone-mimetic properties and described as causing physiological abnormalities, particularly reproductive “ Wikipedia tells us.

How do endocrine disruptors work ?

By interfering with hormonal communication, which is exactly why they are at the heart of our subject!
Along with the nervous system, the hormonal (or endocrine) system is one of the body’s two main communication mechanisms.
However, the thousands of chemicals that have flourished in our environment over the last 50 years (which isn’t very much in retrospect!) could completely interfere with hormonal communication.

How confused ?

Because of the similarity between man-made chemical compounds and hormones – so-called “xeno-hormones”.
To understand this, we could compare our hormones to keys, whose role is to unlock locks (called “receptors”) located in our cells in order to give them a specific action to perform.
However, over the last few decades, we have discovered that these locks (or “receptors”) can be opened, closed or blocked by components that were not intended for them: the famous endocrine disruptors.
What makes their effect so complex to analyze is that, like our hormones, these molecules act at very low doses, so they are not immediately detected as toxic, but disrupt the body discreetly over the longer term.

ENDOCRINE DISRUPTORS MAY ACT IN THREE DIFFERENT WAYS:

1/ Mimicry
Disruptors may substitute for hormones at cell activation sites or receptors, with amplifying or inhibiting effects.

2/ Inhibition
Disruptors block the enzymes responsible for hormone maturation, thus creating a hormonal deficit.

3/ Stabilization
Endocrine disruptors attack the systems that normally manage hormone modulation and degradation, notably emunctory organs such as the liver. As a result, hormones persist in the body and their action is no longer regulated or controlled.

What shocks us

Drastically reduced fertility, exponential increase in hormone-dependent cancers, precocious puberty… pathologies affecting our reproductive system are exploding!
These are organs that are highly reactive to hormones, which lends credence to the idea of increasing hormonal dysfunction.

And while the quality of men’s sperm has fallen considerably in recent years, women are at the forefront of this trend: the incidence of breast cancer (as well as ovarian and endometrial cancer) continues to rise.

Even more worrying for our daughters and future generations: according to an American study, in just 40 years, the average age of breast growth has been brought forward by 1 to 2 years, and this early exposure to hormones increases the risk of pathologies of the reproductive system down the line.

And while most scientists point the finger at the new chemical pollution, “formal” scientific proof is hard to come by, given the complex mechanisms of action of endocrine disruptors…

But don’t we deserve a “precautionary principle” on a public health issue like this?
Already, the European Reach regulation requires manufacturers to provide proof of the harmlessness of the products they put on the market (the reverse seems crazy), but this is already “a first step in the right direction”, far from sufficient…

For their part, industrialists and their lobbies are up in arms in defense of their compounds, attacking the slightest flaw in the studies used against them and, above all, the slightest generalization of a partial result… arguments that are often quite fallacious and the exact opposite of the precautionary principle:
– finding hormonal effects in a substance does not prove its harmfulness: this depends on the duration and extent of exposure” (thus preventing the setting of “thresholds”)
– a demonstration on a rodent or a culture does not prove an effect on humans”.

Yet man is not the only victim, and the devastating effects on the environment are already clearly visible:
Animals at the end of the food chain are traditionally the most contaminated (large fish, birds of prey…): this is how several species of birds of prey have disappeared (concentrating toxic substances, they have become unable to reproduce) and aquatic environments, which concentrate pollutant residues, are also particularly hard hit.
According to Jorg Oehlmann, ecotoxicologist at Frankfurt University, almost 25% of aquatic species are affected by hormonal disorders.

With many cases of feminization of males, attesting to the massive presence of “xenoestrogens” (xeno hormones mimicking the functioning of estrogens in particular – the female hormone par excellence).

And one of the major problems is that this purification of hormones (which we flush down our toilets, for example) and various endocrine disruptors would be very expensive to achieve in wastewater treatment plants, so it’s not possible today.
=> Only a few filters, such as activated carbon filters, would be capable of eliminating most hormone residues and endocrine disruptors.

Where are the main everyday pollutants found?

Stress, smoking and exposure to heavy metals obviously already have a strong impact on our endocrine system (the system that produces and regulates hormones), particularly on the thyroid, pancreas, ovaries and adrenal glands.
And endocrine disruptors, omnipresent in our daily lives (plastics, hygiene products, toys, furniture and textiles, pesticides in food, fish, milk, electronic products, etc.), multiply hormonal imbalances.

The compounds listed below rank 1st among hormone disruptors:
(you can find out more on the very well-done ” Génération Cobayes ” website)

1. Bisphenols
2. Phthalates
3. Parabens
4. Perfluorinated compounds and Teflon
5. Triclosan
6. Pesticides
7. Additives

Phytooestrogens derived from plants (soy, hops…) are also thought to have an estrogenic action, but their life span in the body is much shorter than that of synthetic xenoestrogens (found in the contraceptive pill, non-organic meat and dairy products…), making them much less deleterious.

Plastics and their phthalates are a particular target:
– In 2004, 100% of parliamentarians tested by WWF had phthalates and flame retardants in their blood.
-93% of Americans had BPA in their blood.

This “invisible but very present threat” is completely disrupting our hormonal functioning in the space of just 2 or 3 generations, ruling out any hypothesis of a genetic nature:
the causes are to be found directly in our lifestyle and environment.
So, can we ban all these everyday substances, or at least limit their dosage?
The problem may not be so simple…

Effects: the headache of measurement…

1st problem: determining a “toxicity threshold
The mechanism of action of endocrine disruptors is very complicated to assess: they can have effects at very low doses and have non-linear synergistic interactions, meaning that the effects can multiply rather than add up, which means that there is no room for a “maximum dose” approach to be respected (or “toxicological threshold”).

2nd problem: “an insidious, silent mode of action”.
In fact, most disorders manifest themselves decades after the contamination responsible (an adult cancer may have been triggered by exposure during foetal life).
And it’s very difficult to study and isolate effects over such a long period!
Pollution, pesticides, radiation: humans are exposed to thousands of potentially dangerous agents.
And yet, the effects of transmission at certain sensitive periods of life are now widely documented, particularly at times of high hormonal sensitivity:
Fetal life, puberty, menopause, it’s the “cocktail” effect between our disrupted hormones and endocrine disruptors that can be particularly deleterious!

Once again, xenoestrogens (found in non-organic meats and milks in particular) are of particular concern:
A study conducted by the University of Granada shows that the total estrogen load of women with breast cancer was much higher than that of the general population. ”

ARE WE HEADING STRAIGHT FOR ANOTHER HEALTH SCANDAL?

We are outraged:
Despite the increasingly recognized effects of endocrine disruptors on health, their prohibition or limitation comes up against the powerful lobbying of the petrochemical industry in particular (the source of the most widespread pollutants: phthalates, parabens…), and legislative measures to regulate endocrine disruptors are regularly postponed.
This is a time of real concern: many scientists have joined forces to alert the authorities to the risks of endocrine disruptors, calling for every possible means to reduce the general population’s exposure to chemicals.