Focus: Endocrine Disruptors

Previously in our Medium articles, we discussed the history of pesticides and gave an overview of how they impact our health. Now it’s time for Episode 3 in our series on pesticides:

#1 The Origins of Pesticides 📜

#2 Can Pesticides and Health Live Together? 🚑

#3 Focus: Endocrine Disruptors


#Episode 3

From triclosan in toothpaste, flame retardant in clothes, pesticides in our food…it seems as if endocrine disruptors have become companions in our daily lives. If that’s the case, do we welcome them or do we kick them away? We’ll try to give some answers to the question.

The Endocrine System

Before getting all worked up, let’s start at the beginning. What is our endocrine system, that system that might be disrupted by chemical products that we’re in contact with every day? 🔎

The human endocrine system is one of our body’s internal means of communication. It is an ensemble of organs and tissues that work closely together with the nervous system. It frees hormones that circulate in our bloodstream until they reach their targets, whether in tissues or organs.

As our metabolism is regulated by our hormonal system, the actions of these hormones have a significant impact. They control growth, development and functioning of cells and tissues, as well as our reproductive functions. They also coordinate the metabolic processes within our bodies.

👉 In other words, the endocrine system regulates and coordinates the activity in our various cells (reproductive, nervous, digestive, immune, etc.).

So far, nothing too alarming. “Modify” doesn’t necessarily mean change for the worse. Let’s go a bit further into the various aggressions that our endocrine system may face in order to understand all of the possible impacts.

An imperturbable, well-oiled machine?

It seems that the system can certainly be disturbed, seeing as we refer to “endocrine disruptors”. To better understand their operations, let’s look at the definition proposed by the Endocrine Society. 🏣 Now, this isn’t just an updated version of the dead poets; the Endocrine Society is a group of roughly 18,000 researchers and clinical specialists who concentrate on the endocrine system.

For them, “endocrine disruptors” are 👉 non-natural chemical substances or a mixture of chemical substances that interfere with any hormonal activity 👈

Endocrine disruptors thus modify the physiological actions of hormones. How? Generally by being similar to the targets of those hormones, and by either stimulating or blocking a receptor. There are two types of endocrine disruptors:

👉 Those that are natural: phytoestrogens. In agriculture, some plants have these and the animals that eat them can be affected. Foods such as soy, chickpeas and wheat can contain phytoestrogens.

👉 Those that come from industry: anthropogenic substances. We find these under various names in medicines, cosmetics, plastics, insecticides, fungicides, chemicals, detergents and even paint.

⚠️ According to the Endocrine Society, “Almost 100% of the population has detectable levels of endocrine disruptors in their body!

A recently published French study has backed this up. It measured the presence of various organic pollutants in the urine of over 4000 French women who gave birth in 2011. Bisphenol A was found in more than 70% of the participants, phthalates in 99.6% of them, and dioxins, furans and PCBs in…100% of the subjects. All of these substances are endocrine disruptors that are then passed on to the fetus! 🚑

How Endocrine Disruptors Work

We’re widely exposed to endocrine disruptors. Let’s zoom in on agriculture, that is to say, on the endocrine disruptors found in pesticides.

✅ It is important to not get all of this mixed up, since some pesticides are endocrine disruptors, and some are not. Here are a few examples of those that are (watch out — unpronounceable words ahead):

🐜 The insecticides (carbaryl, chlorodecone, DDT, endosulfan, heptachlor, lindane, methomyl, methoxychlor, mirex, parathion, pyrethroids, toxaphene) control insect populations by interfering with their nervous systems or impeding their molting process. Essentially, we coat them in insecticides so that they can’t get rid of their skin. Still with us?

🌿 The herbicides (benomyl, hexachlorobenezene, mancozeb, maneb, pentachlorophenol, tributyltin, vinclozolin, zineb) control plants by, for example, blocking their photosynthesis. That means that they slow down the process by which the plant feeds itself through its leaves (by capturing sunlight or carbon gasses) or through its roots (absorbing water and nutrients). Gone are the days of plants joyfully sunning themselves in the spring air…

🍄 The fungicides (2,4-D, 2,4,5-T, alachlor, amitrole, atrazine, linuron, metribuzin, nitrophene, trifluralin) slow down amino acid synthesis in mushrooms and interfere in their development. In other words, they stop them from growing. Time for a little nostalgic moment with growing mushrooms: https://www.youtube.com/watch?v=16t6fEZYxmI

Even if all endocrine disruptors have a precise function, there are no endocrine disruptors that are entirely unique to one pest. Living organisms share some common processes and physical mechanisms. There are ways in which our bodies function a bit (a bit) like the bodies of insects and/or plants. In this way, an endocrine disruptor that is meant to combat a pest (an insect or plant) can be potentially toxic for other organisms that it wasn’t intended to target (#us).

Does that mean we’re pests? Not exactly. But in agriculture endocrine disruptors are generally used in open circuits. That means they can then be dispersed beyond their target. They then go into the surrounding environment through irrigation, dispersal through the air, trash burning…And eventually they necessarily get to us. That’s why we’re exposed by eating food, through dust, through water, by inhaling gases and other particles, or through skin contact. Just to say, there’s a very high likelihood that you’ve been exposed over the course of your life.

Just to complicate things a bit, here’s another detail. With these products, it’s not simply the exposure that is toxic, but the relative period of exposure. The most vulnerable moments are during the prenatal period (from the first hours after conception up until birth), early childhood and puberty. No, don’t go calling your parents to ask them for a list of all the times when you could have been exposed. There’s no need to panic, we can simply go on to the possible impacts of these products when we’ve been exposed to them during those key periods of our lives.

Health Impacts

Ah, the touchy subject. We can start by noting that the effects of endocrine disruptors on health depends first and foremost on how the individual’s endocrine system is working. If you’re ready for the Olympics, you’ll be less susceptible than someone who is in a weaker state 🏆

But in general, endocrine disruptors can have toxic effects on an organism and its descendants. As external substances, they can subtly perturb the proper internal functioning of the organism. How? There are multiple ways in which they affect regulatory processes, throwing them off balance. Endocrine disruptors are suspected of being at the root of genital malformations in newborn males, early puberty in young females, sterility, and hormonally-dependent cancers (breast, prostate). Some of these diseases can even be then passed on to descendants.

The first time that these results were seen was with a medicine that is sadly well-known: distilbene, or Diethylstilbestrol (DES). In 1938, Charles Dodds synthesized DES, which would then be used to prevent miscarriages and other complications during pregnancy. In 1953, comparative studies were performed that found it had no positive impact and underlining the its dangers. Almost 20 years later, cases of vaginal tumors were found in girls between 15–22 years of age whose mothers had been given DES during their pregnancies, and its use was then banned in obstetrics. In 1975–76, similar observations were made in France on roughly 200,000 women. The consequences are still visible today, 4 generations later.

The impact of endocrine disruptors on health is real. The example of distilbene is only the first in a long series.

In 1977, we discovered the effects of an insecticide on male fertility: chlorUSdecone was its name. Dozens of workers who manufactured this molecule in the US showed signs, in varying degrees, of a toxic syndrome associated with neurological symptoms and fertility issues. Chlordecone seems to alter the male endocrine system.

Similarly, dibromochloropropane (DBCP for short) quickly distinguished itself. Developed at the end of the 1950s, this product was used until the 1980s to treat bananas in Central America, Southeast Asia and the Caribbean. Notwithstanding toxicological data showing that it reduced sperm production, DBCP was authorized for commercial use in 1964. In 1977, among the workers producing DBCP in factories in the United States, there were the first cases of infertility. The conclusion that the culprit was DBCP was unavoidable and it was banned from the US market in the aftermath. Yet its exportation to the banana fields continued, and it was only years later that dramatic effects on fertility were noted in farmers. Today, there are tens of thousands of male farm workers whose infertility has been attributed, in no uncertain terms, to the use of DBCP.

It is thus known that reproduction is impacted by the use of endocrine disruptors. What’s more, new studies show that for a man in France at 35 years of age, sperm concentration has diminished by 32.2% in 16 years. As a result, couples have more and more problems in having children. The percentage of couples who cannot conceive after 12 months without contraception was 14% in 1991, and rose to 24% in 2012.

The impact of endocrine disruptors goes even further. As we said above, they are suspected of influencing numerous issues: premature births, miscarriages, early puberty, immune problems, breast/testicular/prostate cancers, obesity, diabetes…But there is no one study that allows us to point to the increase in certain problems (breast or testicular cancer, for example) or functional anomalies (lowered sperm quantity or quality) and the use of endocrine disruptors.

The reason why is simple. The data for serious exposure to endocrine disruptors (DBCP, distilbene…) are easily found, while lower exposure levels are more difficult to judge. And it is these lower levels of exposure that are most important in terms of public health. They are levels that affect the largest percentage of the population and that could have a considerable impact on multiple generations.

Ok, So Daily Life…What Do I Change?

The subject of endocrine disruptors is being discussed more and more widely. The level of exposure is increasing and almost no study is today capable of evaluating the potential impact across populations. Yet when in doubt, best to avoid as much as possible! Here are a few tips offered by We Demain. And here’s another one that we’d add: “Try to eat fruits and vegetables that were grown without any pesticides.”