Microplastics: How can we reduce our exposure? 

Hollywood legend and star of James Bond films and Mamma Mia, Pierce Brosnan shone a spotlight on the lifelong health and environmental impacts of plastic in 2022, when he drew an analogy between the Diamonds Are Forever Bond movie and a ‘Plastic is Forever’ campaign.

“Elements of plastic in the things we use, what we eat, even in the air we breathe, can stay around forever,” Brosnan said.

The campaign highlighted how every minute, a rubbish truck of plastic is dumped in the ocean and 83% of tap water, and 90% of bottled water has been found to contain plastic. In 2020, plastic was even detected in the human placenta.

Now, new evidence published in Nature Medicine reports that the brain contains about a spoon’s worth of microplastics and nanoplastics (MNPs) and that levels were 3-5 times higher in those previously diagnosed with dementia.

Microplastics – plastic fragments up to 5mm long - are inescapable. Most come from larger fragments that break down over time, while some are added directly to products such as paints, cleansers and toothpastes.

A review article in Brain Medicine in May, 2025, entitled ‘Human microplastic removal: what does the brain tell us’, reported MNPs found in the walls of blood vessels and in immune cells. Brain tissues were found to have particularly high concentrations of MNPs – 7 to 30 times higher than other organs such as the liver or kidney.

Of note, MNPs in the brain were of smaller size (<200nm) and most often polyethylene. Although MNPs were not linked to factors such as age, race or cause of death, concentrations were 50% higher in people who died in 2024 compared to people who died in 2016.

This suggests that as environmental concentrations of MNPs rise, it aligns with an increase in MNP concentrations in human tissues.

It is estimated that between 10 and 40 million tonnes of emissions microplastics go into the environment every year and this figure is expected to double by 2040.

Microplastics are redistributed by wind and water, aligned with finding them everywhere from the highest mountain to the depths of the ocean.

Microplastics are everywhere – in the food we eat, the water we drink, and the air we breathe. But how is this impacting on our health?

Public concerns over their effects are growing. In the past year alone, headlines have highlighted particles in teabags, seafood, meat, and bottled water.

Health impacts

Studies in animal and human cells suggest microplastic exposure could be linked to cancer, heart attacks, reproductive problems, and a host of other harms. Yet few studies have directly examined the impact of microplastics on human health, leaving us in the dark about potential dangers.

A recent study in the New England Journal of Medicine found that people with a carotid artery plaque where MNPs were detected had a higher risk of heart attack, stroke and overall risk of death.

Added to that, patients with inflammatory bowel disease were found to have about 1.5 times more MNPs in their stools than healthy controls.

Recent evidence of higher levels of MNPs in the brains of people with dementia raises the question: is dementia weakening the blood brain barrier, allowing more microplastics to enter? Or do microplastics, once inside, trigger microinflammation and make it harder for the brain to clear proteins, potentially worsening cognitive decline.

Given the ubiquitous nature of microplastics in the environment, complete elimination is unrealistic. But there are practical ways that we can significantly reduce our exposure.

Cut down on bottled water

A paper in Environmental Science and Technology (2019) suggested that switching from bottled water to tap water could reduce microplastic intake from 90,000 to 4,000 particles per year.

While the average plastic water bottle contains more microplastics than tap, the evidence shows that tap water can also contain microplastics. Using a water filter certified to reduce microplastics can further reduce microplastic ingestion while consuming water.

Avoid storing food in plastic

The light weight and shatter-resistance of plastic make it very convenient when commuting. But avoiding storage of food in plastic and minimising exposing any plastic to high heat will reduce potential exposure to microplastics.

Avoid microwaving or heating food or water in plastic

This includes brewing certain tea bags. Dishwater temperatures run very hot and can degrade plastic – even dishwasher safe plastic can lead to microplastic shedding. Try to wash your plastic containers by hand.

Some researchers suggest that plastic cutting boards can be a significant source of microplastics in your diet, since repeated cutting can dislodge particles that adhere to food.

Highly processed foods, such as chicken nuggets, have been found to contain 30 times more microplastics per gram than chicken breasts, according to a recent paper in Environmental Pollution (2024). This research highlights the impact of industrial processing, which often uses plastics at some point.

Infants and young children

Infants and young children may be particularly vulnerable to higher concentrations of microplastics and nanoplastics.

The evidence shows that this may be particularly important in the early stages of development.

Recent evidence published in Nature Food (2020) shows that polypropylene bottle-fed babies may swallow very high levels of tiny plastics due to the high temperatures used to sterilise bottles and prepare formula, as well as shaking bottles to mix. Experts recommend avoiding using plastic to warm formula or breastmilk.

Handwashing before meals for young kids who eat with their hands can also reduce risk of microplastics on hands being consumed along with their meal.

Microplastics are almost impossible to avoid, no matter how careful we are. The oft-quoted suggestion that we are eating a credit card’s worth of microplastics was questioned in a review in the Journal of Hazardous Materials (2022) and considered a significant overestimation.

But there is clear evidence that our bodies are taking in plastic that we are not designed to be able to handle.

As the body of evidence showing the health impacts of microplastics continues to growth, more public health measures are needed to address microplastic pollution.

In the meantime, there are steps we can take to reduce our exposure.

Cutting down on bottled water, avoiding storing and heating food in plastic, and reducing our intake of ultra-processed foods would be a good place to start.

Dr Catherine Conlon is a public health doctor in Cork