Here's what we still don't know about microplastics in your body

Here's what we still don't know about microplastics in your body

Sorry, Orlando

Photo credit: Getty


The actor Orlando Bloom recently made headlines when he reportedly paid the exorbitant price of £10,000 ($13,600) to have his blood removed, separated and filtered for microplastics.

His rather drastic treatment highlights growing worry over an unsettling truth: there’s simply no avoiding these minuscule particles.

They’re everywhere, from the top of Mount Everest to the inside of our brains, according to some studies. They’re also all over the media, and understandably, the safety of having microscopic flakes of plastic floating around in our bodies has raised public and scientific concern.

Once considered a benign material, microplastics are now being linked to disease. But with the testing at such an early stage and no scientific consensus reached, should we be worried about what it’s doing to our bodies? And should we be queuing up to get our blood ‘cleaned’?

Plastic proof

The term ‘microplastic’ describes any plastic particle or fibre measuring less than 5mm (0.19 inches) in size. Typically, these particles are so small that we need a microscope to see them.

Scientists also use the term ‘nanoplastic’ to describe even smaller particles, which measure below 0.001mm (39.4 microinches). These are challenging to see even with advanced microscopes, but evidence suggests they could be released from plastic materials and into their surrounding environment.

A part of my research group’s work has been to measure the levels of plastic and other particles in the air that we breathe, both outside and indoors. In London, we’ve seen microplastics in the air pollution small enough to travel deep into our lungs.

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To test whether microplastics are in the body, pieces of whole tissue or blood are processed and then filtered to concentrate any microplastic amounts. Then analysis can take place, either through a chemistry technique, which quantifies the amount of plastic in a sample, or a microscope-based physical chemistry technique – i.e. counting the number of plastic particles (and their size and shape) in a sample.

Each method has its merits, but they all share the same drawbacks. The modern laboratory is a hotbed for microplastic contamination, full of plasticware, plastic consumables and, of course, people.

Because of this, the actual process of extracting and testing samples for microplastics can be a source of pollution itself. Often in samples, we see microplastic particles that we’d previously thought were too big to be absorbed and distributed throughout the body.

Why don’t microplastics keep breaking down? © Getty Images
Some reports claim that humans could be ingesting as much as a teaspoon of plastic every day

Generally speaking, particles smaller than 0.001mm (39.4 microinches) in size can cross through your lungs and enter into the bloodstream at the air-blood barrier – a thin layer of tissue in the lungs separating air in the air sacs (alveoli) from blood in the surrounding tiny blood vessels (capillaries).

In the gut, particles smaller than 0.001mm (39.4 microinches) can cross into the lymphatic system – the body’s waste removal structure. From here, the smallest particles enter the bloodstream, and larger particles become trapped in the gut lining.

Contamination from the lab could therefore explain the biggest pieces of plastic found in the body.

Another issue is that some of the biological components in samples generate similar signals to plastics. Specifically, fats interfere with the signals of polyethene and polyvinylchloride, which can lead to an overestimation of how present these plastics are if a sample is not adequately processed. 

With all this in mind, the high amounts of microplastics reported to be in our bodies are likely overestimated. Amounts vary significantly from nanograms to milligrams depending on the study, location, tissue type, and analytical method followed.

In a recent rigorous study, a conservative estimate was made that there’s around 0.15ug – or 0.00000015g – of plastic per millilitre in our blood. To put that into perspective, that’s less than the weight of a single human hair.

Still, it’s also worth noting that this study only looked at polystyrene, as it’s the only type of microplastic that’s easy to test for.

Plastic people

Based on these levels, it’s probably more important to focus on where the microplastics end up in our bodies, instead of how much is actually there.

But again, it’s difficult to measure how much microplastics are gathering in different parts of our bodies. One recent study, for example, suggested the brain is a hotspot for plastic, claiming that it accumulates, on average, 4.5 bottle caps worth.

Not only are these levels relatively high, but the detected plastic is mostly comprised of polyethene – one of the plastics which is difficult to measure around fat.  

Hundreds of millions of tonnes of plastic is produced every year
Hundreds of millions of tonnes of plastic are produced every year - Pexels

Polythene is the main plastic in production globally – around 120 million tonnes is made annually, accounting for 25 per cent of all plastic. It makes sense that we’d see more of this type in the body, generally speaking. The brain is a fatty tissue, however, and false positives can’t be ruled out here.

What’s more, this study suggests there’s more plastic in the brain than in the liver, the organ responsible for cleaning the blood. If there’s a large amount of plastic anywhere in the body, we’d expect it to be there.

Most published studies on microplastics in human tissue have also looked specifically at samples of whole tissue. This means we’re missing important context about whether the microplastics are embedded within cells, or are simply ‘passing through’.

Plastic pure

Whether we can measure them or not, there’s a high level of public anxiety around microplastics. Around two-thirds of 30,000 survey respondents across 31 countries were concerned about microplastics in their bodies.

If you feel like you want to minimise your exposure to microplastic pollution, there are several lifestyle changes you can make. These include opting for natural fibre-based textiles in your home and clothing, avoiding plastic packaging wherever possible (especially where heating is involved) and travelling via quiet streets to avoid tyre wear particles from traffic.

But with microplastic release predicted to increase 1.5 to 2.5 times by 2040, it’s inevitable that tech claiming to remove microplastic invaders from the body will start to appear.

Therapeutic apheresis – a medical procedure which separates blood and selectively removes harmful substances before returning blood to the patient – has recently been commercialised to rid your blood of microplastics.

While there’s no published work on this microplastic removal method, German researchers carrying out the procedure detected ‘microplastic-like’ particles in the plasma of patients. Without information on their lab controls and the sizes of the particles detected, it’s difficult to interpret how meaningful the data is, though.

What’s more, we don’t know how microplastics act in blood specifically. We don’t know whether they’re freely moving around the body and circulating in our plasma, or sticking to our red blood cells, or being engulfed by our immune cells in the bloodstream.

Without concrete evidence on the types of microplastics in our bodies, their journeys or their interactions within the body, it’s almost impossible to interpret the health benefits of these ‘blood cleaning’ ventures.

With all this in mind, until there has been more research assessing the impact of microplastics on our bodies, until we can say where they are and what they are doing, I plan on leaving the sci-fi blood cleaning services to Hollywood.

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