After our recent stories and videos about microplastics, readers submitted hundreds of follow-up questions. Many were practical: Should I stop using my plastic water pitcher? What about plastic retainers for teeth? Aren’t toothbrush bristles plastic?
I get it. There’s a lot still unknown about what exactly microplastics can do to our bodies in the long-term – and a lot of reasonable concern about our everyday exposures. A question we received often was one I’ve asked myself:
What can we do about the microplastics already in our bodies?
The honest answer? We don’t yet have a proven way to remove them, and research on elimination strategies is in very early stages.
Studies have detected microplastics in human blood, lung tissue, liver, placenta, breast milk and even the brain. Some scientists have recently questioned the methods of several prominent microplastics studies that could lead to overestimation, but the overall body of literature points toward a trend of accumulation. What’s a little less clear is the precise health impacts of all these particles. One of the most prominent prospective studies in this field was published in 2024 in the New England Journal of Medicine and looked at patients with asymptomatic coronary artery disease undergoing a procedure to remove plaque. Not only did the researchers find microplastics buried within the plaques of many patients, but patients in whom microplastics were detected went on to have a higher risk of heart attack, stroke and death over the next roughly three years. While this association is highly unsettling, as with many studies in the microplastics literature, it doesn’t prove causation and the possible mechanisms are still being investigated.
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The good news: Your body does clear some of the particles on its own. Scientists believe that the majority of microplastics we eat are likely being eliminated in feces – especially those 150 microns or greater, which are unlikely to cross the intestinal barrier. Small particles are the greater concern: One model estimated that about 30 percent of particles between 1 and 10 microns were absorbed by the human intestine, and nanoplastics (1 micron or less) may accumulate even more readily. (For comparison, 1 micron is a bit smaller than a red blood cell – it’s about 1/100th the width of a strand of hair).
So my focus here is to think about ways to reduce new exposure. Here are some of your other most common practical questions – and what the science has and hasn’t revealed.
I get that microwaving food in plastic can release more microplastics but what about storing frozen food in plastic bags?
Prior studies have found heating plastic aggravates microplastic leaching, though it can also occur, albeit more slowly, during refrigeration over several months. You’d think that freezing food in plastic would be even safer.
Well, here’s where it gets interesting: A small 2022 study from the European Commission’s Joint Research Centre found that when ultrapure water was frozen in plastic bags and then thawed, the thawed water contained detectable particles chemically consistent with the plastic bag material. In comparison, bags stored at room temperature released fewer particles in the same test.
Why this happens is unclear, but scientists speculate that very cold temperatures could cause certain plastics to become brittle and shed differently.
My take: If you only have the bandwidth for a few battles, heating food in plastic is the bigger front. I still use frozen veggies that come in plastic bags – but I’ve stopped heating them in that same plastic. Instead, now I steam or stir fry them on my stovetop. And if avoiding frozen plastics makes it significantly more difficult for you to eat vegetables, I’d rather you eat your veggies any day.
Should I stop using my filtered water pitcher? It’s made of plastic too.
This question is more complicated than meets the eye because you’re actually dealing with two issues: 1) Does the filter remove microplastics from your tap water effectively, and 2) does the plastic pitcher itself shed microplastics after the water has passed through the filter.
Let’s first talk about the typical filters you might see in a standard pitcher, which are granular activated carbon. A ConsumerLab test of several such popular filter pitchers found results that were all over the map: one removed all detectable microplastics, while others reduced them by as little as 36 percent, or – in one case – actually increased the particle count (a reminder to change those filters on schedule!). A handful of pitchers are NSF-certified to reduce microplastics by at least 85 percent, so that’s an upgrade to consider when searching for options. We reached out to one of the biggest manufacturers, Brita, for comment and did not receive a response at the time of publication.
Now onto the pitcher itself. Suppose your water gets filtered and at least some portion of microplastics do get removed. What happens when it sits there in a plastic pitcher for days on end? Many of these pitchers have parts that are made from polypropylene. We know polypropylene can degrade and shed particles over time – although there are other types of plastics in these pitchers about which we know even less when it comes to shedding. But the principle holds that at least some plastics can leach even at room temperature.
One fix: Try to transfer filtered water to a glass or stainless-steel container promptly. If minimizing contaminants is a priority, consider investing in a reverse osmosis system.
Which foods have a lot of microplastics?
Most experts agree that ultra-processed foods are likely the biggest source overall in our diets. Food that comes packaged in plastic is obvious, but there are exposures during industrial processing that we don’t see. That’s one more reason to lean toward whole foods when you can.
A few other surprising sources of microplastics based on limited research:
- Nylon tea bags in plastic. These single-use tea bags are made out of plastic – and one bag steeped in hot water can release more than 11 billion microplastic particles. Try loose-leaf tea with a reusable metal strainer instead.
- Instant rice. A 2021 study found that instant rice contains four times the plastic of regular uncooked rice. I eat a boatload of rice each week so I was relieved to learn that washing your rice can potentially cut the plastic by up to 40 percent.
- Breaded prepackaged nuggets. Breaded shrimp, breaded chicken nuggets – and even processed plant-based nuggets – may contain dozens if not hundreds of microplastics per serving. Whole cuts of protein are the cleaner swap.
- Finally, pink Himalayan salt. Those coarse pink and black salts look fancy but a small 2023 study found terrestrial salts like these may have more microplastics than salts that come from aquatic sources like sea salt.
What about Invisalign or other plastic retainers and toothbrushes?
Yes, all of these release microplastics. A 2023 study documented microplastic detachment from several orthodontic aligners after seven days of artificial saliva exposure due to mechanical friction. The good news is that the majority of the particles detected were on the larger side (5-20 microns), and only a few, Invisalign among them, appeared to release particles less than 5 microns in size. We reached out to Invisalign for comment and did not receive a response by the time of publication.
My take: You wear retainers for several hours daily, and potentially for years on end. That’s a significant cumulative exposure. But the orthodontic benefits are real, and there’s no proven harm from aligner microplastics at this point. Keep them clean with gentle brushing (no hot water) and to avoid eating or drinking hot beverages while wearing them.
Here’s the deal with toothbrushes: Most bristles are made of plastic, which can shed fragments during brushing (some studies estimate dozens of microplastics per day). You could certainly opt for alternatives like boar-hair bristles that come with their own trade-offs. Personally, I’m not throwing out my electric toothbrush over this (nor am I giving up flossing, which, for that matter, is also made from plastic). Oral hygiene matters for your overall health. To me, the far bigger win – with less of a health trade-off – is reducing exposure from ultra-processed foods and plastic water bottles.