You are so full of…plastic

“There are chemicals in your water bottle, in your microwavable plastic and in the packaging of your food that you will ingest”

Plastic is everywhere. You can probably see some right now. You might have drunk from a water bottle, eaten your lunch from Tupperware, and bought vegetables in a plastic wrapper. Whatever you have done today, plastic has almost certainly played a part. I am not here to tell you how bad that is for the environment (which it is). However, I am here to tell you something potentially scarier. That plastic you see around you: It is inside you. Moreover, it may be affecting your health and maybe even your (future) children’s health.

The science

The scary thing about the plastic around us is that a lot of it is water-soluble. That means there are chemicals in your water bottle, in your microwavable plastic and in the packaging of your food that you will ingest. Here is the crazy thing. We know, beyond reasonable doubt, that some of these chemicals are bad for you. They can interfere with and mimic the body’s sex hormones. They can lower male sperm count, decrease libido and cause miscarriage just to name a few causal effects. The evidence is beyond just correlation. There are mouse studies, mechanisms of action evidenced and multiple large-scale investigations in people.

Case study: Phthalates

You have probably heard of BPA (Bisphenol A) and the links between it and harm to female reproductive health. I went with another example that you may not have heard of: phthalates. Phthalates are literally everywhere; they are used to make plastic flexible and as a binding agent. In mice, these compounds have been shown to have huge effects on reproduction and development. For example, one study found that female mice exposed to environmentally relevant levels (that you or I could be exposed to) of just one particular phthalate had a decreased ability to get pregnant after only a 10-day exposure. Even more worryingly, this effect lasted long after exposure was stopped (1).

Receptors ‘signal’ a response. This means that when a receptor binds with the hormone there is a chain reaction within the cell leading to effects such as changed gene expression. Phthalates have similar structures to steroid hormones and so can bind to hormone receptors causing activation of the receptor signalling ‘pathway’. Alternatively, the binding of the phthalate to the receptor can prevent the natural hormone from binding and so can prevent the signal. This is why they are called endocrine disruptors. They can cause too much or too little hormone signalling. This can cause a vast array of effects, from increased cell division to cell death. Phthalates have been demonstrated to cause a vast array of gene expression changes (2).

“It is very clear from the available evidence that we should attempt to limit exposure to phthalates, BPA and other harmful chemicals in plastics especially when pregnant or attempting to conceive”

Phthalates have also been shown to cross the placental barrier, meaning that if a pregnant woman gets exposed to phthalates, then the baby developing in utero will also be exposed. This is very concerning, as this has been shown to cause permanent developmental issues. So not only do these chemicals affect both male and female reproductive health but they also affect foetal development. In 2015, 8-12% of couples worldwide were infertile or had decreased ability to conceive (3) and most studies have found a negative correlation between phthalate exposure and birth weight and birth length (4). It is a real possibility that we will face a world where almost all couples need help to conceive a child.

I am only providing a snapshot of some of the evidence. There have been countless studies in the last 10-20 years linking phthalates and other chemicals with negative health outcomes. It is very clear from the available evidence that we should attempt to limit exposure to phthalates, BPA and other harmful chemicals in plastics especially when pregnant or attempting to conceive. Most of the effects studied have been on reproductive health. Worryingly, there could be many more effects on general and even mental health and there could be many more chemicals that have an impact on human health.

What can we do?

I have been trying to reduce my exposure since researching for this article, and to be honest it is very difficult. As a consumer, this is a bit of a minefield, but I have tried to come up with some easy practical advice.

  1. Not microwaving food in plastic containers is a big one. This is a simple change and the heat from the microwave could be adding lots of chemicals to your food, so this may make a big difference.
  2. Change your water bottles! Mine was made in china and finding out what was in it was impossible. I have changed it for a stainless steel completely plastic free option. Do not be fooled by BPA free or by aluminium, this plastic may still contain other harmful chemicals and the aluminium is coated in a plastic resin.
  3. Get as many groceries as possible from local markets, which will mean the food is fresher, less processed and less likely to be in plastic packaging.
  4. Raise awareness and put pressure on corporations to ensure their practices are safe. Plastic has many good properties and uses, but we need to weigh up the cost versus the benefit. Not just for the planet but for our own health.

There is good news in all of this. Mice studies have shown that when exposure is prevented, the harmful effects observed in the mice can be completely reversed after a few generations. If we can reduce these chemicals in our environment, it could have a massive positive impact on future generations, as well as helping with our fertility in the short term. As long as we keep funding scientific studies and stay willing to change our practices based on new evidence, I have confidence we will be okay.

References

1. Catheryne Chiang, Jodi A Flaws, Subchronic Exposure to Di(2-ethylhexyl) Phthalate and Diisononyl Phthalate During Adulthood Has Immediate and Long-Term Reproductive Consequences in Female Mice, Toxicological Sciences, Volume 168, Issue 2, April 2019, Pages 620–631, https://doi.org/10.1093/toxsci/kfz013

2. Hlisníková H, Petrovičová I, Kolena B, Šidlovská M, Sirotkin A. Effects and Mechanisms of Phthalates’ Action on Reproductive Processes and Reproductive Health: A Literature Review. Int J Environ Res Public Health. 2020 Sep 18;17(18):6811. doi: 10.3390/ijerph17186811. PMID: 32961939; PMCID: PMC7559247.

3. Kumar, N.; Singh, A.K. Trends of male factor infertility, an important cause of infertility: A review of literature. J. Hum. Reprod. Sci. 2015, 8, 191–196.

4. Qian Y, Shao H, Ying X, Huang W, Hua Y. The Endocrine Disruption of Prenatal Phthalate Exposure in Mother and Offspring. Front Public Health. 2020;8:366. Published 2020 Aug 28. doi:10.3389/fpubh.2020.00366

Author

  • Dr Craig Davison has a PhD in Medicine from Queens University Belfast (QUB). Craig has published research investigating novel treatment strategies targeting nucleotide metabolism. Craig is currently working as a postdoctoral research fellow and is passionate about science communication.

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