Documentaries like Blue Planet have helped to increase awareness of the devastating effects plastics are having on the world’s marine life. But some scientists are now also concerned about the impact of microplastics on human health; primarily through our ingestion of them by consuming fish.

In this post, we’ll look at this theory in more detail, and talk to Clinical Director Dr Daniel Atkinson about how microplastic consumption could be affecting us.

Firstly: what are microplastics?

We can think of microplastics in a similar way to sand. Grains of sand were once part of a larger structure of rock, and came to be after years of erosion and fragmentation - essentially breaking down into smaller and smaller pieces.

The same is true of microplastics and much like sand, they are not going away any-time soon.

In an article by the National Geographic examining plastic in our oceans, Elizabeth Royte writes that microplastics have been found in 114 aquatic creatures, half of which humans eat. So, because plastic has found a way into our oceans, and into fish that inhabit the sea, it has also found a way into our bodies.

Certainly in Western countries, where people are becoming ever more concerned with what goes into their food, it may seem odd that microplastic finding its way into our digestive system is not a more prevalent news story. But this is likely because research in this area is still comparatively sparse.

A joint study on microplastics conducted by Medical University of Vienna and the Environment Agency Austria has estimated that more ‘than 50% of the world population might have microplastics in their stools’, after conducting an experiment that found for every 10g of excrement 20 microplastic particles were found.

Why are microplastics bad for our bodies?

In an annual report, which discussed the broader impacts of pollution on health in general, the UK’s Chief Medical Officer wrote of microplastics that ‘there is an absence of toxicological data that has meant that effective risk assessment is not possible.’

The report did however go on to highlight three main areas of medical concern, including:

  • physical toxicity such as blockage of the gut,
  • chemical toxicity arising from chemicals released from the particles that could be plastic monomers, colourings and plasticisers and;
  • lung damage such as inflammation and secondary fibrosis.’

Another physical toxicity aspect Elizabeth Royte raises is the potential for liver damage, which was observed in some fish that consumed treated plastics (although it’s not known if this would also be an issue in humans).

The report by the Chief Medical Officer notes that the risks are unquantified.’ Dr Atkinson tells us. ‘So at this stage, the impact on human health is largely theoretical.’

'But looking over the report, it seems as though the digestive tract, lungs, liver and kidneys are the areas of the body they think could be impacted the most. For example, it’s possible that ‘blockage of the gut’ caused by long-term microplastic consumption could conceivably lead to digestion problems and inflammation of the lining of the intestine.’

‘And chemical toxicity caused by microplastic consumption may perhaps give those organs that deal with filtration - namely the liver and kidneys - more work to do. But once again, at this stage, it’s not clear how much extra pressure (if any) these organs would be subject to.’

What is being done about the microplastics problem?

It’s estimated that around 12.7 million tonnes of plastic enter the ocean every year, and this figure is rising. Much of this will break down and form microplastics. Some commentators argue that current legislation curbing plastic use doesn’t go far enough.

If you are concerned or worried about the impacts microplastics may present to your health, or more broadly the environmental dangers plastic presents to our oceans and wildlife, do whatever you can to cut your plastic use.

Some ways you can cut your plastic use include carrying reusable water bottles and coffee cups, avoiding plastic straws, taking canvas bags to the shop with you, investing in reusable household plastic alternatives and recycling often and efficiently.

If everybody does their part, we could cut plastic in our oceans, therefore inside ourselves, drastically.

To avoid microplastics, should we stop eating fish?

There are other reasons why we should limit our fish consumption to the NHS recommended two portions a week.’ Daniel notes. ‘Perhaps the most pressing of these right now is that many types are being overfished and are in danger of extinction.’

‘The research we’ve talked about is at a very early stage, and when consumed in moderation, fish does have various health benefits and can form an integral part of a healthy balanced diet.’

‘For now, it’s probably more sensible not necessarily to avoid eating fish altogether if you normally eat it - but to make sure you eat varieties which aren’t at risk, and strictly limit your consumption of species which are in danger.’