Microplastics Are Everywhere: Could Fibre Help?

If you’ve eaten, drunk or breathed today, you’ve almost certainly been exposed to microplastics.

That’s not a scare tactic. It’s simply a reflection of how widespread these tiny plastic particles have become. But an interesting question is beginning to emerge. Could something as ordinary as dietary fibre influence what happens to microplastics once they enter the body? It’s an intriguing idea, but the science is still in its early stages. Here’s what we know, what we don’t, and where fibre might realistically fit in.

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What are microplastics and why are we talking about them?

Microplastics are exactly what they sound like: tiny pieces of plastic, generally smaller than 5 mm.¹ Some are manufactured at this size. Others form as larger plastic products, which gradually break down through sunlight, friction and everyday wear. Go smaller still and you reach nanoplastics, particles so tiny they’re measured on a microscopic scale.¹  The concern isn’t simply that these particles are all around us. Researchers are now finding them inside the human body.¹  The conversation has shifted from “plastic is polluting our environment” to “what happens when some of that plastic makes its way into us?”

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Where we're actually exposed

Microplastics are difficult to avoid because exposure doesn’t come from one obvious source. These tiny particles have been detected in the food we eat, the water we drink and the air we breathe.¹

• Food and drink: Microplastics have been detected across a wide range of foods and beverages, including bottled water, tap water, seafood, salt and even honey.² Food packaging can also contribute, with plastic bottles, containers, cups and some tea bags capable of releasing tiny particles.¹

• Air: Microplastics aren’t only something we eat or drink. Tiny particles and fibres can become airborne as plastics and synthetic materials gradually wear down. Textiles, carpets, furnishings and other household materials can all contribute, meaning some of these particles may be inhaled.²

• Clothing: Synthetic fabrics such as polyester, acrylic and nylon can shed microscopic fibres as they’re worn and washed. Some of these fibres enter wastewater and can make their way into waterways and the wider environment. It’s one of the less obvious ways our everyday clothing can contribute to the wider microplastic problem.^2,3

• Household products and packaging: The way we store and prepare food may also influence exposure. Plastic containers, cling wrap and other packaging can release small particles over time, particularly when plastic is heated, worn or damaged.^1,2

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What do we know about the body's response?

We know that some of these particles can make their way into the body. Microplastics have been detected in human blood and tissues including the liver, placenta, bone and brain.⁴ The bigger question is what their presence actually means for our health.

A 2024 study published in the New England Journal of Medicine found that people with microplastics and nanoplastics detected in carotid artery plaque had a higher risk of heart attack, stroke or death during follow-up than those without.⁵ Importantly, this doesn’t prove that microplastics caused these outcomes. But it has added to growing interest in their potential role in inflammation and oxidative stress.

There is an important caveat. Much of what we know about the biological effects of microplastics still comes from laboratory and animal studies rather than large human trials. There are enough signals to warrant further research, but we still don’t know what everyday microplastic exposure means for long term human health.

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What happens to microplastics in the gut?

Many ingested particles appear to pass through the digestive system and leave the body in our stool rather than being absorbed.⁶ Researchers are more interested in the smallest particles. Very small microplastics and particularly nanoplastics, may be more capable of crossing the gut lining and entering the bloodstream, potentially allowing them to travel to other tissues in the body.⁶

There’s also growing interest in the gut microbiome. Early research suggests microplastics may alter the balance of microorganisms living in the gut and affect the health of the gut lining.⁷ However, much of this research is still experimental.

While we may be exposed to microplastics throughout much of our lives, experimental studies often examine exposure for just 24 hours to four weeks. That makes it difficult to know what decades of everyday exposure might mean for human health.⁷

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Could dietary fibre help? What emerging research shows

This is where the research gets interesting. Scientists have proposed several ways dietary fibre might influence what happens to microplastics in the gut.8

• Trapping particles: Insoluble fibre may be able to bind or trap some microplastic particles in the gut, potentially helping them move through the digestive system and be excreted. 

• Keeping things moving: Insoluble fibre adds bulk to stool and helps move material through the digestive system. In theory, this could reduce the amount of time microplastics spend in contact with the gut lining. 

• Supporting the gut barrier: Fermentable fibres feed gut bacteria, which produce short-chain fatty acids such as butyrate. These compounds help support the health and integrity of the gut lining, raising the possibility that fibre could also influence how the gut responds to microplastic exposure.

 

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So, where is the science at?

The idea that fibre could help “flush” microplastics from the body is intriguing. But there’s an important caveat, which is, we don’t yet have good human trials showing that eating more fibre reduces microplastic absorption. Most of the evidence behind these proposed mechanisms currently comes from laboratory and animal research.⁸  So, while you may see claims that fibre can remove microplastics from the body, the science isn’t there yet to support that kind of certainty. What we do know is that eating enough fibre has well established benefits for gut health, bowel regularity and metabolic health. If future research shows that it can also help the body deal with ingested microplastics, consider that an added bonus.