Microplastics are increasingly finding their way onto the headlines. I’m sure you have seen the horrifying lakes of plastic waste in the oceans. Aside from the huge environmental damage, what are the health risks of microplastics in food?
What are Microplastics?
Approximately eight million metric tons of plastics enter the oceans annually and conservative estimates suggest 5.25 trillion plastic particles currently circulate in ocean surface waters (1).
When plastics are exposed to natural forces like sunlight and wave action, they degrade into smaller pieces. These are called microplastics when they measure less than 5 mm in size (1). Even smaller plastic particles are called nanoplastics which are less than a 1000th of a millimetre.
Where is microplastic contamination found?
Human activity has led to microplastic contamination throughout the marine environment, with microplastics ingested by many species of wildlife including fish and shellfish. In the marine environment, microplastics accumulate most in the gastrointestinal systems of fish and shellfish.
Microplastic contamination unfortunately isn’t just confined to the marine environment, land based food chains, including fruit and vegetables have also been found to be affected. Due to the widespread contamination of our food chains, it is now well established that humans ingest microplastics as well.
Microplastic contamination also occurs from food and drink packaging. Drinking water from plastic bottles substantially increases your risk of exposure.
What are the Health Risks of Microplastics in Food?
Nine different types of plastic found in human stool (2) and this really reflects one of the problems of microplastic contamination. There are so many different types of plastic chemistry, coupled with different physical properties such as fibres, beads etc, that the spectrum of contamination is huge. It is almost worth considering each type of plastic as a different personality with different risks. This makes calculating the health risk of microplastics in food more challenging, as there are so many different varieties.
In general, microplastics are associated with chemicals and bacteria both from manufacturing and also that are absorbed from the surrounding environment (1,3). Microplastics may also release their constituents along with contaminants and pathogenic organisms that coat the surface of the plastic pieces. Therefore, there is concern regarding both potential physical and chemical toxicity from contamination of our food (1).
Animal studies have shown that nano plastics can be found in all organs of the body (1). The consequences of long term exposure to microplastics is not well understood and more research is needed.
However, there is growing concern that ingested microplastics can interfere with the friendly gut bacteria (microbiome), leading to dysbiosis (imbalance of the gut bacteria). This many then disturb the host immune system and trigger the onset of chronic diseases, and promote pathogenic infections, further disturbing the microbiome (4).
Our immune system is not set up to remove synthetic particles, so this can lead to chronic inflammation and an increased risk of cancer (3).
What can you do to Help Reduce your Risk of Microplastic Contamination?
Unfortunately, because of widespread contamination of our food chains, exposure to microplastics is almost guaranteed. However, there are some ways that you can avoid try to limit your exposure:
- Avoid / limit eating shellfish and fish (for example muscles, oysters) consumed with intact guts pose particular concern because this is where microplastics accumulate and are retained.
- Avoid drinking liquids from plastic bottles, for example tap water instead of bottled water.
- Avoid using plastic straws.
- Recycle.
- Try to avoid using plastics to help reduce global consumption and waste.
References
1. Smith M, Love DC, Rochman CM, Neff RA. Microplastics in Seafood and the Implications for Human Health. Curr Environ Health Rep. 2018 Sep;5(3):375–86.
2. Schwabl P, Köppel S, Königshofer P, Bucsics T, Trauner M, Reiberger T, et al. Detection of Various Microplastics in Human Stool: A Prospective Case Series. Ann Intern Med. 2019 Oct 1;171(7):453–7.
3. Prata JC, da Costa JP, Lopes I, Duarte AC, Rocha-Santos T. Environmental exposure to microplastics: An overview on possible human health effects. Sci Total Environ. 2020 Feb 1;702:134455.
4. Fackelmann G, Sommer S. Microplastics and the gut microbiome: How chronically exposed species may suffer from gut dysbiosis. Mar Pollut Bull. 2019 Jun;143:193–203.
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