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Endocrine Disrupting Chemicals (EDCs) aka knocking your hormones off course: what are they, how bad are they and how can you realistically avoid them?
There has been a lot of research linking EDC exposure to problems with getting and staying pregnant (including a recent study on declining sperm count) and adverse effects on a baby’s health; particularly when it comes to brain development, behavioural issues and propensity to disease in the future.
This is, in all honesty, a bit of a minefield, for several reasons:
What even is an EDC? Aren’t they literally everywhere?!
How much damage do they really cause, and how?
Which are the worst offenders?
How on earth (ex living in a bubble) can you really avoid them? (Click here for more)
Errmm…isn’t this all a bit daunting and depressing?!
One of the things we don’t want to do is sensationalise and depress you with a lot of scary facts and seemingly few solutions. The reality is that our world is full of these chemicals, but my aim is simply to provide awareness, show you where the most risky ones are and how they work, then provide some ways to avoid them where you can. It’s a bit like driving a car down a dark road the risks are a lot lower if you just switch your lights on!
Now, the evidence and science around EDCs (as with many things) isn’t perfect, and it continues to evolve. Nothing is conclusive and a lot of the evidence is based on animal studies. However there is an excellent research paper (for the hardcore!) by the Endocrine Society, which has helpfully collated and analysed hundreds of studies. Usually when I research each topic I use multiple sources, but amazingly the Endocrine Society has done it for us this time (thanks!) The link to the full paper is at the bottom of the article. In case you don’t have time to read a 250 page monster here are the key need to know:
What is an Endocrine Disrupting Chemical?
The definition the Endocrine Society uses is: ‘an exogenous chemical, or mixture of chemicals, that interferes with any aspect of hormone action.’
What does that mean in English? Something that can knock are all important hormones off balance – not what you want when you’re trying to have a healthy little person!
Now we know that hormones are the basis for all of our life processes. They are the way the body signals what to do and when. We also know that there are a vast number of potential consequences when they are knocked off their natural course; but problems with fertility, conception and the development of a healthy baby are what we’re most concerned with.
So, which are the main EDCs to watch out for?
BPA (found in plastics)
Phthalates (commonly found in added fragrance amongst other things)
Pesticides and Herbicides (you know where to find those)
PCBs/PBDEs (found in things like flame retardants)
Where are they found?
Here’s some of the not so good news…
BPA: This mimics oestrogen and its use is unfortunately prolific. In fact, there is more BPA produced annually than any other chemical! Most typically it is used in food packaging, toys and canned foods and beverages. Another concern is that it becomes more dangerous when exposed to heat, when physically manipulated and repeatedly reused. This is why plastic water bottles – especially if you refill them or don’t know where they’ve been stored – are not good. Frighteningly 93% of the US population is said to have measurable amounts of BPA in their urine. It has also been detected in breast milk.
Phthalates: These are often used to soften PVC (make plastic bendy) and are also used as solvents, in household cleaning products and in things like cosmetics and consumer products (avoid anything with added ‘fragrance’, which is often derived from phthalates.) They are also found in flooring, toys, detergents and some food packaging. They are also often found in recycled plastics, particularly PVC. Tricky!
Pesticides: We know how prolific the use of these are globally, with atrazine (a very common herbicide most often used on corn) often said to be one of the worst culprits, amongst others. There is the well known ‘feminised frog’ study in which male frogs exposed to even relatively low levels of pesticides in water became feminised. Click here to learn more.
PCBs/PBDEs: The good news is that PCBs have been banned, but they are known for their longevity and tend to bioaccumulate. Unfortunately there isn’t much we can do about them, except be aware. However PBDEs are used in flame retardants, certain upholstered products and things like mattresses. They are pretty widely used in the US, and although certain forms are banned in Europe and Asia not all are, so it’s worth being aware.
PFCs: Typically found in non-stick pots and pans but also in certain pesticides and furniture.
How do EDCs potentially impact us?
It all comes down to their ability to throw your natural hormone balance off course and the knock-on consequences of this, the severity of which will depend on when you are impacted, for how long and the size of the dose, plus your own particular genetic susceptibility. Typically EDCs work by:
Binding to hormone receptors: either enhancing, dampening or blocking
Altering the number of hormone receptors in different cell types
Altering the concentration of circulating hormones
Translation: they potentially stand in the way of our bodies operating as they should.
For our purposes, you really don’t want to have too much exposure during pregnancy: ‘If exposure alters hormone actions during ontogenesis (the very earliest development), the effects are often permanent and can affect organ development and function. Furthermore, these effects could have lifetime consequences that are both complex and difficult to predict. The extent and nature of long-term consequences depend on the interaction of genes and environment and involve many variables, including the developmental window of exposure, the individual’s metabolism, and his or her genetic background.’ (1)
What do EDCs actually do? And when do they do it?
Well, BPA was discovered to be estrogenic (mimicking oestrogen) in 1936, for example. However, their impact also depends on the stage of life. When it comes to trying to get pregnant, obviously having your hormones in top shape matters. Similarly when growing a baby there are periods of very rapid development, so pushing things off course here is also less than ideal (click here for a reminder): ‘The targets of endocrine glands typically exhibit heightened sensitivity to hormones during specific developmentally critical windows.’ (1)
So there is an effect on fertility? And by which chemicals?
Once again – it depends on the amount and level of your exposure over time:
There are a wide range of studies – human and animal – that have shown some of the effects of high levels of EDCs and issues with getting pregnant and staying pregnant, so the answer is yes: ‘Several studies indicate that EDCs can adversely affect the ovary, uterus, vagina, anterior pituitary, and/or steroid production, which can lead to reproductive disorders such as early puberty, infertility, abnormal cyclicity, premature ovarian failure/menopause, endometriosis, fibroids, and adverse pregnancy outcomes.’ (1)
BPA and pesticides look to be the worst offenders.
When it comes to BPA, as stated above it is known to mimic estrogen, and has a number of consequences when seen in high levels: ‘Previous studies provide strong evidence that BPA adversely affects the postnatal ovary by inhibiting follicle growth and/or increasing atresia/apoptosis.’ (1)
Click here to read more about the ‘Estrogen generation’ that we are increasingly becoming.
In human studies BPA has also been shown to have an impact on hormone levels during IVF, including a study which showed a link between higher quartiles of urinary BPA concentrations and increased odds of implantation failure. Similarly, BPA levels were higher in infertile women when compared with fertile women. Other studies in rats showed issues with embryo implantation, pregnancy maintenance and reduced fertility with age.
When it comes to pesticides: ‘Studies conducted during the past 5 years confirm previous studies that pesticides alter gene expression, impair follicle growth, increase atresia, and reduce oocyte quality in the postnatal ovary.’ (1) Translation: not good for anything pregnancy-related; potentially impacting development (our old friend epigenetics, where the environment turns on and off certain genes) and also potentially affecting the quality of the eggs we produce.
Pesticides also exhibit an effect on thyroid function: studies in animals showed that Atrazine adversely affected the function of the anterior pituitary gland: ‘Prior to the past 5 years, several studies indicated that pesticide exposures reduce fertility or cause infertility in animal models. These previous findings have been confirmed in more recent studies.’ (1)
Phthalates have also been associated with endometriosis: (click here to learn more on how this condition can impact fertility) ‘Several studies have focused on whether phthalate exposure is associated with an increased risk of endometriosis and suggest that there is an association.’ (1)
A study in Korea showed that women with advanced stages of endometriosis had significantly higher plasma levels of MEHP and DEHP (phthalates) than women without advanced stages of endometriosis. In another study, women with endometriosis had significantly higher levels of total urinary phthalate than controls. In fact: ‘In the Natural History, Diagnosis, and Outcomes Study, six phthalate metabolites were significantly associated with two-fold increased odds of endometriosis’. (1)
Once again, none of these studies are cut and dried, but, there is enough evidence here suggesting that it is better to err on the side of caution and try to avoid EDCs wherever you can.
If that wasn’t enough – sperm count has been declining globally – this has been linked to EDCs. There was a recent study (on rats) looking at various levels of exposure during pregnancy and following and showing that ‘Enviromental chemical mixtures affected sperm count at the lowest mixture dose indicating an insufficient margin of safety for the most exposed humans. Click here for much more on this.
Development of a baby
We know by now that when it comes to a baby developing optimally, preventing the mother’s body from doing its job is NOT what you want. Click here for more on this.
Of course EDCs are a prime potential culprit knocking this process off course: ‘During embryonic development…and tissue differentiation we proceed through a series of tightly regulated and temporally coordinated events…ultimately resulting in a functional, mature structure. Natural substances such as hormones as well as environmental changes, including exposures to exogenous environmental chemicals, alter this unidirectional process.’ (1)
It is relatively unequivocal that if these processes are upset we will encounter potentially lifelong problems:
‘Overt toxicant exposures during gestation have been recognized for decades to cause adverse outcomes in exposed children…there is growing appreciation that development during the critical period is particularly vulnerable to the effects of exogenous EDCs that can reprogram essential signaling/differentiation pathways and lead to lifelong consequences.’ (1)
So there is enough evidence showing that certain substances, particularly at high levels, that can knock our hormones off-balance are not good.
Brain development has been studied closely in relation to EDCs. It is important to note that nothing is yet conclusive, but, ‘parts of the brain function as an endocrine gland’ so it would be naive to assume that anything that disrupts your hormones significantly has no impact on a developing brain:
‘The brain’s dense and widespread distribution of hormone receptors, its high hormone sensitivity…among other characteristics, make it particularly vulnerable to hormonal perturbations. This concept is particularly important when put into the context of development because there are critical periods during which even minute changes in hormone exposures can affect a neurobiological outcome.’ (1)
In fact there is quite compelling evidence that EDCs do in fact change the expression, abundance, and distribution of certain hormone receptors in the developing central nervous system. At the moment the science suggests that the most potential damage seems to come from PCBs and BPA.
‘What is still very controversial is whether there are direct links among environmental EDCs and specific disorders such as autism spectrum disorders, attention deficit hyperactivity disorders, and others, although the hypothesis has been postulated that EDCs may contribute to the increasing prevalence of these disorders.’ (1)
At the moment the science here is limited and much more work has been done on animal vs. human development, so there is a limit to the conclusions we can draw, particularly on the behavioural side. That being said we do know more about general cognitive function and IQ. For example, some of the earliest historical evidence on EDC exposure was via studies conducted on pregnant women living near Lake Michigan (where concentrations of PCB were relatively high). It was discovered that children of mothers with the highest exposures had lower average IQ and poorer performance on reading comprehension. Since then other studies (looking specifically at PCB concentration in the mother and child) have found similar results.
All of the above may seem a bit scary and overwhelming but its worth remembering that ultimately as with most things in life it is about THE AMOUNT of exposure we get – so being aware and minimising exposure where you can is the smartest strategy to allow the body to do its magnificent work growing a small person.
Click here to read our top ten ways to avoid exposure. For the hardcore out there here is the 250 page research paper by the Endocrine Society with a lot more information!
(1) A. C. GORE, V. A. CHAPPELL, S. E. FENTON, J. A. FLAWS, A. NADAL, G. S. PRINS, J. TOPPARI and R. T. ZOELLER: EDC-2: The Endocrine Society’s Second Scientific Statement on Endocrine-Disrupting Chemicals. November 2015.
This article is for informational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice. The information on this website has been developed following years of personal research and from referenced and sourced medical research. Before making any changes we strongly recommend you consult a healthcare professional before you begin.
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