[INFORMATIVE] A Meta-Analysis of Microplastics and their effect on human health.

A Meta-Analysis of Microplastics and their effect on human health.

By Meshari Mohammed Aldagher

Abstract
Microplastics have become omnipresent in the environment, including what we consume, inhale, and even skincare products. Although there is limited research, microplastics have garnered interest for their possible negative implications. This meta-analysis examines current research about the effect of MNPs on human well-being. Research has pointed towards the idea that the presence of microplastics in the lung can cause inflammation and impaired lung function, alongside having various other effects in other parts of the body, increasing your risk of a heart attack or stroke, dying within the next three years, endocrine disruption, skin cancer, and many other effects.

How do MNPs have a potentially detrimental impact on your well-being?
There’s more than one cause, the main culprit of microplastics is that they can absorb undesirable chemicals, such as polychlorinated biphenyls (PCBs), and environmental pesticides [2]. Human consumption of microplastics can increase exposure to these chemicals. It might lead to poisonous effects as they’ll seep into whatever organ they reach, especially if said plastic is heated, which breaks down the plastic further into microplastics. A recent NEJM (New England Journal of Medicine) study [1], titled “Microplastics and Nanoplastics in Atheromas and Cardiovascular Events” from March of this year, suggests that patients who suffered from asymptomatic carotid artery disease, a non-symptomatic disease of microplastics in the blood vessels on either side of the neck in the carotid arteries, were twice as likely to suffer a heart attack or stroke. To be more precise, all these patients had carotid artery plaque, and the people explicitly with MNPs detected in it suffered from these symptoms with a 95% Confidence Interval. In addition, these patients had a higher chance of dying within the next three years than those in the study group who didn’t have microplastics in their arteries.
Another way microplastics can harm your well-being is through your lungs. Plastic fibers can deposit and build up in the lung tissue [3]. Extended exposure to microplastics can result in respiratory illnesses such as asthma and pneumonia. MNPs may also be linked to endocrine disruption, weight gain, insulin resistance, decreased reproductive health, and skin cancer [4].

How do MNPs get to your bloodstream and or organs?
There are numerous ways, some being plastic water bottles [5] (especially ones that have been heated, as that breaks down the plastic in the bottle further), consumption of commercial table salts [6], application of cosmetics/skin care products [4], and air fryers.

Air fryers and PTFEs
As briefly mentioned, heated plastic is a breeding ground for microplastics, with most air fryers' outer coating being plastic, which may seep into the food. Secondly, concerns have been raised about the non-stick coating seeping into foods. For example, the Philips air fryer [7] can reach 400 degrees Fahrenheit. PTFE (non-stick coating) begins decomposing at 482 Fahrenheit, with significant decomposition noticeable at 600 Fahrenheit [8]. A result of this seeping into food or being inhaled is polymer-fume fever [9], which has flu-like symptoms. While it is not quite at the decomposition temperature, it is close, and due to how common air fryer use is for some people, in addition to the PTFE in air fryers degrading over time, PTFE and microplastics are bound to seep into your food. While polymer-fume fever is a more obvious threat, as mentioned earlier, microplastics are linked to plenty of things that aren’t easily detectable. PTFE can be found in many more things, like pans, and can even leech into you through PTFE-contaminated tobacco and welding near PTFE components [10]. PTFE has also been found to be lethal to birds [11].

Possible generational effects
Due to the ubiquity of microplastics in our everyday lives, whether it be food, drink, or even air, a recent study in January 2023 has found MNPs in the placenta (with an average abundance of 2.70 ± 2.65 particles/g and a range of 0.28 to 9.55 particles/g). This implies that MNPs don’t just leech at you. They can even be transferred to your children through the placenta by the consumption of MNP-infected things. The implications of this are significant, and in looking at the side effects mentioned earlier, the health of many people may be affected by MNPs in some capacity, even before birth.

Airborne MNPs and their effects
[12] Plastic has unique advantages that promote the migration of micro-organisms due to its chemical stability and durable nature, Airborne microplastics not only provide shelter from UV radiation but also nutrients, which adds the factor of airborne disease to the detrimental impacts of MNPs. The proper term for this is Plastisphere, novel microbial communities distinctly attached to plastic. Although studies on pathogenic microorganisms and airborne microplastics are still limited, MNPs in aquatic environments have been suggested to be able to absorb micro-organisms, forming a Plastisphere. So, it is reasonable to guess that airborne MNPs or Plastispheres carry pathogenic micro-organisms. [13] Another issue of microplastics is their cytotoxicity. Vitro testing has shown that PS (polystyrene particles) may induce cytotoxicity in erythrocytes, macrophages, and rat alveolar epithelial cell lines. Microplastics not bound to a membrane may cause cytotoxicity while interacting with cells, damaging cellular structures. Possible responses to this may be dust overload or oxidating stress caused by said plastics due to the atmospheric pollution they cause. The body’s primary immune mechanism, clearance, is also caused to be activated to protect the airways from foreign particles by using four mechanisms: sneezing, the mucociliary escalator, where particles are excreted from the mouth, phagocytosis, where foreign particles are consumed and transported by macrophages, and lymphatic transport. These mechanisms effectively remove atmospheric microplastics, but some will inevitably reach your lungs. Because of their high surface area, they are difficult to remove from the body, and over time, this may cause intense and chronic inflammation. [14]

To conclude this Meta-Analysis, I’ve covered the omnipresence of MNPs, their possible generational cycle, and their various detrimental effects, from the chronic inflammation of the lungs and skin cancer to the higher risk for heart disease. I hope you’ve enjoyed the information presented in this article, and that you use it wisely.

References:
[1]: Marfella, Raffaele, et al. “Microplastics and Nanoplastics in Atheromas and Cardiovascular Events.” New England Journal of Medicine, vol. 390, no. 10, Mar. 2024, pp. 900–10. https://doi.org/10.1056/nejmoa2309822.

[2]: Johnson-Arbor, Kelly. Are Microplastics Harmful? Jan. 2021, www.poison.org/articles/are-microplastics-harmful.

[3]: Pauly, John L., et al. “Inhaled Cellulosic and Plastic Fibers Found in Human Lung Tissue.” PubMed, vol. 7, no. 5, May 1998, pp. 419–28. pubmed.ncbi.nlm.nih.gov/9610792.

[4]: Enrique, Navarro-Frómeta Amado, et al. “Human Skin and Micro- and Nanoplastics: A Mini-review.” MOJ Ecology & Environmental Sciences, vol. 9, no. 3, June 2024, pp. 122–25. https://doi.org/10.15406/mojes.2024.09.00315.

[5]: Zhou, Xue-Jun, et al. “Microplastic Pollution of Bottled Water in China.” Journal of Water Process Engineering, vol. 40, Apr. 2021, p. 101884. https://doi.org/10.1016/j.jwpe.2020.101884.

[6]: Kim, Ji-Su, et al. “Global Pattern of Microplastics (MPs) in Commercial Food-Grade Salts: Sea Salt as an Indicator of Seawater MP Pollution.” Environmental Science & Technology, vol. 52, no. 21, Oct. 2018, pp. 12819–28. https://doi.org/10.1021/acs.est.8b04180.

[8]: Zapp JA, Limperos G, Brinker KC (26 April 1955). "Toxicity of pyrolysis products of 'Teflon' tetrafluoroethylene resin". Proceedings of the American Industrial Hygiene Association Annual Meeting.

[9]: DuPont Website, accessed via Wayback machine Snapshot in 2012. Titled “Key Questions About Teflon® Nonstick Coatings”

[10]: National Center for Biotechnology Information (2024). PubChem Annotation Record for, TEFLON, Source: Hazardous Substances Data Bank (HSDB). Retrieved August 13, 2024 from https://pubchem.ncbi.nlm.nih.gov.

[11]: Griffith, Franklin D., et al. “Exposure of Japanese Quail and Parakeets to the Pyrolysis Products of Fry Pans Coated With Teflon® and Common Cooking Oils.” AIHAJ, vol. 34, no. 4, Apr. 1973, pp. 176–78. https://doi.org/10.1080/0002889738506828.

[12]: Zhu, Long, et al. “Identification of Microplastics in Human Placenta Using Laser Direct Infrared Spectroscopy.” The Science of the Total Environment, vol. 856, Jan. 2023, p. 159060. https://doi.org/10.1016/j.scitotenv.2022.159060.

[13]: Airborne Microplastics: Analysis, Fate and Human Health Effects. Elsevier, 2023.
Reference Chapter 7: page 171

[14]: Airborne Microplastics: Analysis, Fate and Human Health Effects. Elsevier, 2023.
Reference Chapter 8: 203-208