Beware of The Plastics

Some of you may have heard by now of the concept of microplastics, and how they might be affecting our environment and our health.

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But what actually are they, and how much of a problem are they really?

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Microplastics and nanoplastics are tiny pieces of plastic that are environmental pollutants and have been found in many places, including food, water, and the bodies of humans and animals.

‍Microplastics are pieces of plastic that are typically less than 5 millimeters in size, but can range from 1 micrometer to 5 millimeters. Nanoplastics are even smaller: they are typically less than 1 micrometer in size, but can range from 1 nanometer to 1 micrometer.

They are typically divided into two categories: Primary (which are plastics that are designed to be small, such as resin pellets or plastic fibers) or they are Secondary (which are small pieces of plastic that break down from larger plastics, such as food packaging, tires, or synthetic textiles).  

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Where do they come from? 

We are unfortunately becoming more and more aware of how widespread these particles are.

We are seeing evidence of “Bioaccumulation”, which is the buildup over time of microplastics in the bodies of animals and humans.

We are also seeing evidence of “Biomagnification”, which is how microplastics can move up the food chain, affecting higher levels of the food web. For example, as smaller fish with microplastics get eaten by bigger fish, the microplastic content “magnifies”. And if you then eat that bigger fish, those microplastics are now in you. 

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Where are we getting it from? Everywhere (unfortunately). 

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In a study that came out in 2024, sixteen types of protein sources, including chicken, beef, seafood, pork, tofu and three plant-based alternatives, were analyzed and found that >90% of the food items contained microplastics. Highly-processed products contained the most microplastics per gram. The more a food is processed, the more likely it is to have microplastics. Chicken nuggets (highly-processed) had significantly more microplastics than chicken breasts. This research team found that the amount of microplastics in the food items ranged widely, from 2 ± 2 particles in chicken breast to 370 ± 580 in breaded shrimp. Overall, seafood had higher levels than “terrestrial” forms of protein, but the seafood they mostly evaluated was shrimp (and the breaded shrimp had the highest content of all). The other marine-based protein they looked at was Alaskan Pollock, which is what fast food restaurants mainly use in their fish sandwiches.

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Importantly, not even processed plant-based food is safe from microplastic contamination. The researchers looked at meat substitutes like plant-based nuggets, plant-based fish sticks, and plant-based ground beef; they all had high levels of microplastics too, as did tofu blocks.

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Some of this issue is due to the packaging that the food is in. For example, bottled water is known to contain higher levels of MP than tap water. But microplastics have even been detected in glass-bottled water, which means they are getting in there via another route earlier in the process.

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And of course plastic food containers have also been shown to release millions to billions of sub-micron nanoplastic (NP) particles into the food or liquid it is holding when exposed to high heat in a microwave or similar setting. So make sure to transfer your leftovers OUT of the restaurant take-out container before you reheat them.

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Another study was able to show that plastic cutting boards were the source of microplastics in some food items.

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How big is this problem?

It is a HUGE problem. The mean U.S. adult exposure from consuming these proteins is estimated at >11,000 microplastics/year. But the maximum exposure for some people is actually estimated at ∼3.8 million microplastics/year!

To put this in perspective, previous research suggested that humans consume a credit card’s worth of plastic every week on average.

Unfortunately, we are now beginning to see their potential health effects, and it may only be the tip of the iceberg.

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Some of the effects that are being seen are the potential for neurological damage, as microplastics can interfere with brain function and structure, potentially causing Alzheimer's disease, dementia, and Parkinson's disease. 

There is also concern for reproductive harm, as microplastics and plastic chemicals can harm fertility and reproductive health.

And of course there is likely cardiovascular harm, too.

Animal experiments have suggested that microplastics may promote atherosclerosis. More recent research has shown that it is a problem for humans as well.

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Another study from 2024 study looked at 257 people with blocked carotid arteries (those are the ones in the neck that feed the brain) who were scheduled to have surgery to clear out those blockages. These researchers used microscopes to look at the plaque specimens AFTER they were cut out and removed.

They found microplastics in these plaques, of course.

Electron microscopy revealed visible, jagged-edged foreign particles among plaque macrophages and scattered in the external debris. Radiographic examination showed that some of these particles included chlorine.

About 58% of participants had polyethylene in their carotid artery plaques and about 12% had polyvinyl chloride.

But even more importantly, they also found that the people who had microplastics in their carotid artery plaques had about a 4.5-fold higher risk of having a heart attack or stroke or dying of any cause in the next three years than those who did not. 

Now this was an “observational study”, which means that the researchers couldn’t definitively conclude that exposure to MNPs caused poor cardiovascular outcomes. But it certainly raises questions.

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OK, what can I do to avoid microplastics?

Reduce processed foods

Limit seafood consumption

Reduce plastic use: Avoid single-use plastics like plastic bags and cling wrap. Instead, use reusable bags, glass, metal, or wood containers. Especially those with recycling codes 3, 6, and 7

Drink filtered tap water, stored in glass or steel water bottles

Avoid heating food in plastic

Use reusable utensils 

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It can be scary to think about what is really in our ecosystem, and the effects it may have on our health. But we can all make some changes to our lifestyles to minimize the risk and harm, and those changes can actually have magnified benefits over time.

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At Wisconsin Cardiology Associates, we have always counseled our patients to aim for a healthy, plant-based diet, rich with unprocessed whole foods like fruits, vegetables, beans, lentils, whole grains and nuts. Have questions about the best way you can prevent heart disease? Call us and make an appointment for a consultation.

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References:

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Milne, MH et al. Environmental Pollution Volume 343, 15 February 2024, 123233

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Marfella, R et al. N Engl J Med. 2024 Mar 7;390(10):900-910.

Liu Z et al. Sci Adv 2023;9(46)

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