Expert Reveals 5 Surprising Sources of Microplastics in Your Daily Diet

The public is starting to understand that they can find microplastics in their food, particularly seafood, but exposure from other foods is far more common than most people realise.

Studies have shown that your daily intake of microplastics from food and drink is estimated to be anywhere from zero to 1.5 million microplastic particles per day. The biggest source is likely to be coming from bottled water.

Here are five of the more surprising sources of microplastics in your food and drink.

1. Chewing gum

When you chew gum, you are essentially chewing a lump of plastic. Most chewing gum is made from a gum base (plastics and rubber), to which sweeteners and flavourings are added. As you chew, the gum base releases microplastics. A single gram of chewing gum can release up to 637 microplastic particles.

Natural gums made with plant polymers are not much better. They release a similar number of microplastics as the synthetic gum. This suggests that microplastics aren't just coming from the gum base but could be due to the introduction of microplastics during the production or packaging process.

Most microplastics were released within the first eight minutes of chewing, so to reduce your exposure, chew one piece of gum for longer, rather than constantly popping in fresh pieces.

2. Salt

Salt may seem like a pure, simple ingredient, but studies have shown that 94% of salt products tested worldwide are contaminated with microplastics. The contamination is so widespread that sea salt has even been proposed as an indicator of microplastic pollution in the marine environment.

Contamination has been found to be higher in terrestrial salts, such as Himalayan salt, rather than marine salts. New technologies are being investigated to help clean up sea salt; however, it is likely that much of the contamination comes from production and packaging.

Your salt grinder might also be making things worse. Disposable plastic spice grinders can release up to 7,628 particles when grinding just 0.1g of salt using a plastic grinder. To minimise your exposure, switch to a grinder with a ceramic or metal grinding mechanism and store salt in non-plastic containers.

3. Apples and carrots

Microplastic contamination of fruit and vegetables has been identified in several studies. Nanoplastics, which are plastic particles smaller than 1,000 nanometres, can enter plants through the roots. Microplastics have also been found on the surface of a variety of fruit and vegetables.

One study found apples and carrots to be the most contaminated and lettuce the least. However, microplastic contamination remains relatively small when compared with more highly processed foods.

While we don't yet know what the effects of the microplastics are, we do know that antioxidants in fruit and vegetables, such as anthocyanins, which give fruits and vegetables their red, blue, and purple colours, keep people healthy, so keep eating them.

4. Tea and coffee

Teabags are not the only source of microplastics in your hot beverage. Tea leaves, coffee, and milk can all be contaminated with microplastics. The use of disposable plastic-lined takeaway cups is one of the biggest sources of microplastic contamination in hot drinks. High temperatures can cause the release of microplastics from the container into the beverage.

Hot drinks contain more microplastics than the iced equivalents, so switching to a cold beverage can reduce your exposure. Buying milk in glass bottles has also been shown to result in a lower microplastic load.

This doesn't extend to all drinks, though. A study of bottled drinks demonstrated that soft drinks and beer stored in glass bottles had higher microplastic contamination than plastic bottles, possibly due to contamination from the painted metal bottle caps.

There are a few truly plastic-free teabags available – they use cotton rather than biodegradable plastics to seal their bags. Identifying these brands, however, can be tricky as there is no standard approach to labelling and not all companies are transparent about the composition of their product.

Overall, switching to loose leaf tea and using metal or glass reusable cups are good strategies for reducing microplastic contamination.

5. Seafood

While studies have shown that most seafood is contaminated with microplastics, what is perhaps most surprising about seafood is the amount of attention it receives compared to other food sources.

One study showed the levels of microplastics in so-called "filter feeders", such as mussels, were just 0.2-0.70 microplastic particles per gram. This is significantly less than the 11.6 billion microplastics released when brewing a single cup of te....

Other steps you can take

Storing food in plastic containers and eating highly processed food are both associated with high concentrations of microplastics in stool samples, so you could try to avoid these. Microwaving food in glass containers rather than plastic is also a good idea to prevent microplastics from leaching into your food.

Finally, the single biggest source of microplastics in food and drink is likely to be bottled water, with up to 240,000 particles per litre. Switching to tap water can help to significantly reduce your exposure.

While eliminating plastics entirely from our diets may be impossible, making these swaps should help to reduce your exposure.

Author:

Catherine Rolph, Lecturer in Environmental Engineering, The Open University

This article is republished from THE CONVERSATION under a Creative Commons license. Read the original article.

Simply using your food packaging in the manner it's supposed to be used is enough to contaminate your comestibles with a sprinkling of microplastics.

A painstaking review of 103 scientific studies on microplastic food contamination found actions as simple as opening a plastic drink bottle or using a plastic chopping board can shave off tiny particles of common polymers.

Even glass bottles that use a plastic gasket, plastic-lined pizza boxes, plastic-lined disposable coffee cups, plastic tea bags, plastic wrappings, and microwaveable plastic containers shed microplastic like a Persian cat sheds fur in spring.

The problem, a team led by biologist Lisa Zimmermann of the non-profit Food Packaging Forum in Switzerland says, is ubiquitous.

"This is the first systematic evidence of how normal and intended use of foodstuffs packaged in plastics can be contaminated with micro- and nanoplastics," Zimmermann told CNN.

"We found food packaging is actually a direct source of the micro- and nanoplastics measured in food."

The more scientists look into micro- and nanoplastics, or MNPs, the more we see just how widespread they have become. These are tiny pieces of material, too small to see, released by a variety of polymers as they're used or break up in the environment.

Plastic is ubiquitous in our modern society, providing a cheap, easily manufactured solution to everything from storage to clothing to furnishings. In recent decades it has become clear its resistance to degrading doesn't mean it is impervious to crumbling into smaller fragments, which easily filter through ecosystems.

Studies have found microplastics throughout the human body, including placentas. It's been found in every major organ in mice, including their fetuses.

What makes this even more worrying is that we just have very little idea about the health impacts, although it's not looking promising: A study last year found that cardiac and stroke patients with a high concentration of microplastics in their carotid artery plaque had a significantly elevated risk of death.

Zimmermann and her colleagues examined 103 studies that have investigated the presence of plastic particles in food and food simulants. From these studies, they extracted 600 entries about food contact articles, of which 96 percent reported the presence of MNPs.

Those entries were also compiled into a searchable and filterable dashboard that anyone can access, allowing users to home in on different types of food contact articles, from packaging to baby bottles, as well as different types of plastic.

Of particular note, the researchers found, is that multiple studies found that for some reusable plastic items, such as melamine bowls, the amount of microplastics shed increased with each wash. This suggests that repeated heating and abrasion increases the rate at which these items degrade.

The researchers also note that ultra-processed food contains more microplastic than minimally processed food. The reason for this is simple: more processing steps mean greater exposure to plastic food-processing equipment, resulting in more MNPs in the final product.

Their findings, the researchers say, strongly indicate that not only is a lot more research warranted, but also that more needs to be done to minimize the use of plastics in food packaging and preparation.

"Our study shows that under intended or foreseeable conditions of use, plastic food contact articles can release MNPs into foodstuffs," they write in their paper.

"The contribution of plastic food contact articles to human MNP exposure is currently unclear and warrants further investigation. Further research is also necessary to establish human health impacts associated with MNP exposures, but a precautionary approach aimed at limiting human exposure to MNPs, including from food contact articles, is prudent."

You can access the interactive dashboard here, and the paper has been published in npj Science of Food.

ByMichelle Starr

Expert Reveals 5 Surprising Sources of Microplastics in Your Daily Diet

1. Chewing gum

2. Salt

3. Apples and carrots

4. Tea and coffee

5. Seafood

Other steps you can take

Replies to This Discussion

Your Food Packaging Is Shedding Microplastics Into Every Meal, Study Reveals

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