Americans eat about 200 tiny pieces of plastic every day. Too much plastic in our diets could mess with our health in mysterious and scary ways.
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- Microplastics - tiny plastic particles smaller than a sesame seed and often thinner than a human hair - are ubiquitous in our modern environment.
- They come from larger plastic debris that gets broken down, as well as microbeads in beauty products and microfiber towels.
- A new study suggests people in the US eat about 200 of these tiny plastic pieces per day.
- We don't yet know what these microplastics are doing to our bodies, but evidence suggests that eating food and drinking beverages out of plastic containers can mess with our hormones, scramble our reproductive systems, and make us fatter.
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Think for a second about what you have eaten today. Chances are, pieces of plastic aren't on your list.
But they should be.
A study published Wednesday in the journal Environmental Science & Technology suggests that microplastics - tiny, often invisible pieces of plastic - are in our water, food, air, and stomachs at alarming rates.
The researchers compiled data from 26 studies, looking at 3,600 samples of food and drink sources including seafood, salt, sugar, honey, beer, and water from the tap and bottles. They also looked at microplastic concentrations in the air, indoors and out. Then they calculated how much of these substances the average person eats and breathes in every day, based on recommended dietary intakes, consumption data from the Department of Agriculture, and estimates from the US Environmental Protection Agency (EPA).
Their numbers suggest that Americans take in between 203 and 312 bits of plastic every day, depending on our age and sex.
Over time, that adds up: The average American woman may ingest around 98,000 tiny plastic particles every year, while the average man consumes 121,000.
Bottled water drinkers have it the worst. They ingest about 86,000 more microplastics per year than people who drink from the tap. That's an extra 236 small plastic particles every day.
Scientists aren't yet sure what health risks these microplastics pose for humans, but here's what we know so far.
Yeah, we eat and drink plastic. So what?
The most common microplastics we eat are fibers (like those from microfiber cloths), but we also take in plastic fragments, plastic granules that can be as big as sesame seeds, and tiny bits of foams and films. Plastic even comes into our noses.
"Unless coughed or sneezed out of the mouth or nasal openings, inhaled particles will either enter the digestive system via mucociliary clearing or remain trapped in the lungs," the researchers said in the study.
The World Health Organization says there isn't yet enough evidence to conclude that microplastic particles are hurting us, since so little data is available. But research conducted in other creatures does not look good. Evidence shows that microplastics hurt sea life and slow down growth and reproduction rates in fish.
It's not yet known whether the tiny particles are dangerous for us on their own, but scientists do know that they contain toxic chemicals that have been shown to have detrimental health effects.
One category of these chemicals is phthalates, which are found in plastic packaging. At least one phthalate can cause cancer, according to the US National Institutes of Health. Phthalates can also mess with our ability to make babies and can impair normal child development. Over the past five decades, sperm counts have plummeted: Researchers have found that men today produce about half the sperm they did in the 1970s across North America, Europe, Australia, and New Zealand. There is some initial evidence this trend may be linked to more plastic use. Plasticizing chemicals may also be linked to decreases in male testosterone levels.
Microplastics also contain the chemical BPA, which is often used in the lining of canned foods and drinks. A survey conducted in 2013 and 2014 by the Centers for Disease Control suggested that 95% of US adults have detectable levels of BPA in their bodies. There's evidence that this BPA exposure can make our bodies turn more calories into fat rather than muscle, and can make our fat cells larger.
"BPA exposure may explain nearly 2% of all obesity in 4-year-olds," Leo Trasande, a pediatrician and public-health researcher at NYU Langone Health who was not involved in the new study, told Business Insider.
In a best case scenario, any chemicals in microplastics will simply pass through our bodies without causing damaging effects. But even if that is the case, we are not safe from the harmful effects of plastic on a larger scale.
Chemicals from plastics are a problem on their own
Transande said that because research about the health effects of microplastics on humans is still so preliminary, it's hard to know whether the amount we're consuming is a problem.
"There's very little one can actually take away from this particular study," he said. "I can't tell you what these microplastics do. They may get excreted in feces, they may get absorbed into the human body."
But chemicals like phthalates and BPA pose a risk to people who consume food or liquid stored in plastic, regardless of whether or not they ingest any microplastics.
"Yes, microplastics are a rising concern for human health, but when it comes to the effects of plastics in food and in health, there already are many substantial health concerns known about the chemicals that absorb into food directly," Transande said. "We really should be focusing on action to limit contact of food and water with chemicals commonly found in plastic."
Transande added that he recommends people avoid dishwashing or microwaving any plastic containers, because the heat can cause toxic, endocrine-disrupting chemicals to leach out into what we eat. Opt out of plastic packaging and storage containers when possible, he said, and throw kitchen plastics away when they become etched or scratched.
The new numbers could be low estimates
More research on microplastics is still needed, and there are some important caveats to note about this study. For one, the researchers only estimated how many microplastics we ingest - they didn't measure the concentrations inside people's bodies. So it's possible their counts are off.
The team's totals are also not comprehensive. They did not calculate how many microplastics people take in from some common everyday foods like meat, grains, and vegetables, for example, because there isn't much information available about the microplastic concentrations in those (data is better for things like seafood and water). The studies we do have suggest foods like chicken contain detectable amounts of plastic.
What's more, the researchers didn't include estimates for any additional microplastics that may get added during food preparation, and they didn't consider the microplastics that might accumulate on top of food while it's sitting out waiting to be eaten either.
So the authors cautioned that, if anything, their numbers are underestimates.
In reality, our "annual microplastic consumption could exceed several hundred thousand," the researchers said.
Whatever the real total is, the only way to reduce it is to produce and use less plastic overall. This would lead fewer tiny pieces of microplastic to accumulate in the environment, and would ensure that humans consume less of the toxic chemicals found in plastic products in general.
"It speaks to reducing the use of plastic materials in your daily life when it comes to contact with food, period," Transande said of the new research. "Because ultimately the reason that we're seeing microplastics in the environment is the ubiquitous use of plastics."