How Endocrine Disrupting Chemicals Negatively Affect Health

I recently posted an introduction to endocrine disrupting chemicals/compounds (EDCs) giving an overview of the topic as briefly as I could while still providing the relevant information. I just touched on some of the negative health impacts of EDCs and promised to share more in the future. Well, here we are!

Today I want to dive a little deeper into the research on how endocrine disrupting chemicals negatively affect health. We will discuss what areas of health EDCs can impact, when the impacts can be the greatest, and what the current research says and does not say about their impacts. I’ll start by briefly overviewing the general health areas of importance and break them down a little further in the article.

When are the impacts of EDCs most severe?

Negative Health Impacts of EDCs

Summary / TLDR

As we discussed in the introduction to EDCs, endocrine disrupting chemicals appear to negatively impact neurological and behavioral health, capacity to cope with stress, metabolism, fertility, growth and development at various stages of the lifespan, and cancer. Let’s look a little bit at when EDC exposure is likely to cause problems before we dive into those problems.

When are the impacts of EDCs most severe?

We also discussed that, though the negative health outcomes can be experienced throughout the lifespan, the points at which the origin of the outcomes occur are most likely during “windows of vulnerability.” These windows refer to periods of time during which hormonal regulation is particularly specific and important for optimal development.

These most important times seem to be in the months preceding conception (the exposures of conceiving parents), the fetal period, early childhood, and puberty, with mention of concern particularly in the area of carcinogenic damage for older adults. EDC exposure is always important and always causing problems, but it is at these points that the body is utilizing small changes in hormones to control various developmental processes. 

A baby in utero is, obviously, developing very rapidly and small changes can cause big impacts. This rapid development continues throughout the first several months of life and even, though it begins to slow, through the first couple years of life. Think for instance about the fact that a woman is born with all of her eggs. Well, aside from genetic impacts from her mother, any issues in the actual form and function are likely to occur in that fetal period. Though they can be impacted at other points in life, it’s possible for damage to occur at this point that isn’t reversible. We’ll talk more about this when we talk about fertility. 

Then obviously when an individual goes through puberty, that process is massively controlled by hormones, with changes to this system being detrimental. We’ve seen over the last couple decades several issues with pubertal development, things like earlier onset of menstrual cycles, which we will also discuss more within that section. 

All of that to highlight that, though always important, it is especially important to be mindful of EDC exposure during these key times of life. Obviously, we cannot go back and change our exposures during utero, early childhood, and puberty, but we do have the wonderful blessing (and maybe difficult burden) of protecting our children during these times. I don’t say that to make you fearful or put you into a panic. 

However, I don’t want to sugarcoat the issue. It is very important that we help our children in these areas. The beauty of being in charge of these little humans is that we do have the ability to support their health and set them up for health, if we’re willing to put the effort in.

Negative health impacts of EDCs

Now for what you’ve probably come here for: specific health areas the EDCs negatively impact. Let’s get into the research. 

An important note, we aren’t running around exposing people to known EDCs to gather data on their impacts. Obviously, that would be unethical. We rely mostly on animal models and evaluating human samples like urine and blood to determine EDC levels and draw associations based on statistics of health outcomes or issues. It’s not the most clear area of science in so many ways. As with many things to do with the human body, it’s complicated, difficult to assess, and can be influenced by many variables. However, the methods we use are sound and I am presenting the best data that we have available to us today.

A lot of what I cite are reviews of current literature, rather than individual studies. I did this to cut down on excessive linking and because I think with this topic it’s important to see a lot of different data points, because some of them conflict. As I said, the picture can be complicated, and I wanted to use sources that note this and show the conflict as well as provide the most helpful analyses. There are also many other reviews that support the conclusions of the ones I’ve cited that I didn’t fit in.

Neurological and behavioral issues

As I’ve already said and will probably say seven more times, it can be difficult to say what is causing specific health outcomes because they are impacted by so many variables. This can be especially true when it comes to neurological and even more so “behavioral” issues because you have to go far beyond even physiological processes into psychological, cultural, and so many other facets of human living. 

However, there does appear to be an indication that higher exposure to EDCs in utero is potentially associated with neurobehavioral issues later in life.

I’m not going to lie, this health outcome is the one that I was like, “no way, really? I’m not sure if I can believe that.” Nonetheless, the evidence is promising. 

Though the complete effect of EDCs on neurology is not fully understood, it does appear that EDC exposure impacts various parts of nerve functioning, including plasticity, specific neurons (especially dopaminergic neurons), and even sex-specific differences. Work specific to neurological structure appears to be mostly animal.

However, there is work being done in the neurotoxicity arena that utilizes human samples, and some of this work, in combination with animal studies, has shown potential links with psychological disorders like depression as well as impaired neuronal development, which can impact cognition, memory, and certain related diseases. Some of the issue appears to come from the fact that a lot of EDCs mimic estrogen, which plays a large part in neural development.

There have been decent studies analyzing both exposure to individual chemicals and multiple chemicals that do indicate that issues with cognitive traits, from IQ to externalizing behaviors, and certain disorders, may be linked to EDC exposure, at least in part. Some have more support than others, such as increases in prevalence of ASD or related traits having more support than ADHD, though there is some for that too. Additionally, certain chemicals have more research than others, such as bisphenols, flame retardants, and pesticides showing strong evidence for some of these links, with others having much less research.

And as with most EDC issues, the issue seems to be most critical in fetal development, as, obviously, the brain is being built and developed during this stage particularly quickly and fetuses seem to be very sensitive to impacts. Though there are some studies analyzing postnatal exposure to EDCs in relation to neural development and related behavioral issues (which is important because the brain continues to develop into early adulthood), the quality and quantity are both very limited.

Somewhat related to neurology but could have its own category is the potential impact of EDCs on capacity to handle stress. I decided not to include this as its own category because, though I’ve seen reliable sources state this may be an issue, I’m not seeing much research for it. It may be buried in other research. It makes sense that EDCs could impact stress management as hormones are a massive part of stress control, and stress, in a way, is a hormone, but I can’t be clear on the actual significance of any links to this.

Metabolism

Part of the problem with metabolic disorders and obesity is that the research is beginning to reveal that the main contributors, such as caloric intake, physical activity, and sleep, alone don’t seem to be the only factors and that there may be other environmental issues going on. One that has gained traction in recent research is EDCs. Though limited, the research does support that the effects of EDCs on the endocrine system, which majorly impacts metabolism, do appear to be contributing to the issue of metabolic disorders and obesity.

It seems that in utero and the early years may be of critical importance as changes to metabolic systems and organs as well as epigenetics due to EDC exposure are being linked to obesity and even potentially that other impacts of these changes are causing the body to increasingly accumulate lipids. This is all animal study but it’s very interesting and promising. The epigenetic effects likely cause transgenerational effects in this area like we see in others.

Obviously, this is an area of health where it’s going to be difficult to say X is causing this, because there are so many factors involved, some that are very clear and some that are less clear. However, the evidence keeps growing that EDCs may very well be part of the issue, contributing to increases in obesity, fat accumulation, and other related negative health outcomes.

I’ll note that BPA has been most strongly linked with obesity, but evidence is growing for other EDCs as well, especially herbicides, as one of these other sources explained. 

Fertility

It’s pretty clear that EDC exposure impacts fertility in both males and females. Evidence of this can be seen in animal studies and studies that measure human samples during processes like IVF for levels of EDCs and draw associations with outcomes. Not a perfect method but the best we have for this.

Some of the specific effects have to do with decreased testosterone and estradiol and estrogen levels. Since these hormones control most of the steps along the way to creating a viable pregnancy, that’s obviously not great for fertility. 

For males we’re seeing patterns in the research such as decreased sperm count, motility, and quality, which is incredibly important to creating a pregnancy and can impact the sustainability of one as well. We’re also seeing decreased testosterone levels, which likely impacts these markers.

For females, we’re seeing issues related to quality of eggs as that decrease the likeliness of viable pregnancy. This in combination with impacts to various hormones involved in pregnancy, such as bisphenol impact on estradiol, appear to be leading to increased miscarriage rates as well as lower rates of fertilization and implantation. While it seems exposure during time immediately trying to conceive is extremely important, impacts across the adult, reproductive years will contribute to these negative effects. Again, while the research can be mixed and difficult to parse out, it does appear that individuals with fertility issues exhibit higher levels of EDCs in samples than those that do not.

Maternal and fetal health during pregnancy

There is some evidence that suggests EDC exposure may be related with development of certain negative health outcomes during reproductive years, such as diabetes, hypertension, and cardiometabolic abnormalities. We have strong evidence that those negative health outcomes cause big issues for pregnant women and the children they carry. Think things like preeclampsia.

If EDCs are increasing the risk of these negative health outcomes, that would be very concerning. However, while there is decent evidence for the relation between EDCs and development of those health outcomes, it is limited and complicated, as those outcomes are impacted by many factors. The best evidence is for the link between bisphenol and phthalate exposure and negative pregnancy outcomes, especially preeclampsia and related issues, but the research is growing for other EDCs as well.

Things like increased risk of gestational diabetes and preeclampsia due to EDC exposure have slightly more research behind them but it’s still limited. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10648368/

Additionally difficult to prove but a pattern that seems to be emerging in the literature is that fetal development may be impacted in utero by EDCs due to a potentially increased susceptibility to epigenetic changes that EDCs can cause, and because EDCs seem to pass the placental barrier. A lot of these effects have to do with low birth weight and other measures of size, potentially in relation to increased risk of fetal growth restriction.

Further, because of the nature of EDCs impacting hormone function, it appears they may mess with the hormones of both pregnant mothers and fetuses in ways that do impact growth and development. The mother’s hormones affect the baby and the baby’s hormones have impact, obviously. There are also markers that EDCs impact placental health negatively as well. 

Cancer

One interesting note before we dive into cancer specific research, is on the potential link between obesity and excessive adipose tissue (fat) with cancer. I include this because it’s helpful to know that fat carries EDCs in it, potentially because some EDCs are non-metabolizable, and fat will hold on to them. The level at which they’re then excreted back around the body is difficult to know but relevant when considering the decent links between obesity and cancer and considering that fat holds EDCs.

EDCs are potentially linked in the literature with hormone dependent cancers, particularly estrogen related cancers. This is why most of the research and evidence exists to show that cancers such as prostrate, breast, or cervical cancers, among others, may be related with EDC exposure. Perhaps the strongest evidence exists for the link with breast and endometrial cancer, and there is again note that this effect may be somewhat transgenerational.

However, this (again!) is difficult to say with certainty, as there are many factors. Nevertheless, the link appears strong enough that pregnant women are encouraged to avoid exposure due to potential carcinogenic effects for their children later in life.

Summary / TLDR

This was a lot. I don’t even blame you if you skipped right to this TLDR section. That is what it’s here for. I know most people don’t have time to sift through all of this. Here’s the basics.

If you read our first post on what endocrine disrupting chemicals are (LINK), you learned that EDCs are chemicals that impair the functioning of the endocrine system, mostly by mimicking or blocking hormones and negatively impacting the ability of hormone-producing and -responsive cells to perform their jobs. These jobs are to produce and regulate the levels of various hormones in the body that perform a lot of very important functions to basic life and to development. 

EDCs can be particularly impactful during “windows of vulnerability,” which are periods of time that the body is developing very rapidly and in ways that rely in a major way on hormone regulation. These especially vulnerable times are in utero, the first several years of life, puberty, and the reproductive years (because of the impact that EDC exposure can have on fertility and fetal development).

Some key areas that EDCs impact are neurobehavioral issues, metabolism, fertility, maternal and fetal health, and cancer development and progression. 

The research shows potential links between EDC exposure during vulnerable times with higher incidences of neurological issues, such as cognition and memory, as well as depression, anxiety, ASD, and ADHD. 

Links have been found between metabolic disorders, fatty liver disease, and obesity with EDC exposure, with particular attention to exposure in the fetal and early years. 

Perhaps the most heavily researched area, fertility has been strongly associated with EDC exposure during all of the windows of vulnerability as well as potentially from previous generations’ exposures. Impacts include lower quality of semen testosterone production as well as decreased egg quality, higher risk of miscarriage, and greater difficulty with successful fertilization and implantation. There’s perhaps more concrete evidence for male infertility in relation to EDC exposure than female infertility, though that evidence is strong as well.

Preliminary links have been shown with several maternal health outcomes that impact pregnancies, with the strongest being a higher risk for preeclampsia and related complications. For the fetus, we see links between EDC exposure in utero and fetal growth restriction and low birth weight. It’s also a strong current throughout the research that, as I’ve said, EDC exposure in utero impacts so many areas of health due to the importance of endocrine regulation in the development of many of the body’s systems and processes. 

Finally, we see that EDC exposure at various points of life appear to increase the odds of hormone-dependent cancers, especially estrogen-related cancers like breast and ovarian cancer.

That’s so much. It sounds scary. And to be honest, it is. EDCs are causing issues and they aren’t going anywhere. That’s just something we have to deal with. However, we do have some ability to control the level of exposure for ourselves and our children. Our children actually have a very exciting chance at experiencing less of these negative effects if we do successfully reduce their EDC exposure before and after they’re born. 

As always, there’s only so much you can do. Unfortunately, a few centuries of poor management and use of chemicals has led to levels in the environment that pose a risk and are not going anywhere. Our soil, water, and air are all impacted and we cannot totally avoid exposure. If you want to learn ways you can reduce exposure, and places EDCs may be hiding in your life, stay tuned for a post on that coming soon.

In theory, if we collectively work to reduce our load and the load of our children, we can create healthier future generations. We will obviously never be able to control what the world around us is doing, and at this point there will always be some unavoidable exposure. However, we should do the best we can, advocating for change in our homes and, where possible, in the world around us.

I hope you found this post helpful. If you enjoyed this content and want to see more, please consider subscribing to our newsletter and browsing our other posts. We have many great topics for you to gain knowledge in and take control of your health.