It’s not just takeout containers and teabags.
Microplastics have infiltrated nearly every corner of our lives, including our diets, with Americans estimated to consume thousands of these pesky particles each year.
But some everyday staples are worse offenders than others.
Scientists have identified the three top protein sources with the highest levels of microplastic contamination — and found that switching brands or grocery stores may not do much to lower the number that ends up on your plate.
In the study, researchers at the University of Toronto and Ocean Conservatory examined 16 types of commonly consumed protein products, including seafood, poultry, beef, pork and plant-based alternatives.
The samples were purchased from two conventional supermarkets and one grocery store specializing primarily in natural and organic products in the Portland, Oregon, area. Researchers also bought fresh-caught seafood directly from fishing boats.
In a lab, they used chemical solutions to break down the food itself, leaving only plastic particles behind. They then filtered the remaining material and examined it under microscopes.
The researchers found that 88% of the 111 food samples they tested contained microplastics, with at least one contaminated sample found among each of the 16 protein types.
“There’s no escaping them no matter what you eat, it seems,” Dr. Britta Baechler, a marine biologist and co-author of the study, said in a press release.
Breaded shrimp topped the list of most contaminated products, containing an average of 370 microplastic particles per serving.
Plant-based nuggets came in second, averaging 73 particles, followed by conventional chicken nuggets at 62 particles for a typical helping.
Pollock fish sticks and plant-based fish sticks rounded out the top five, containing averages of 58 and 46 particles per serving, respectively.
At the other end of the spectrum, chicken breast had the lowest amount, averaging just two particles per serving. Pork loin chops followed with four, tofu with seven, minimally processed Alaska pollock with nine, and fresh-caught White Gulf shrimp with 10.
The findings suggest that the way food is processed may play a major role in microplastic contamination, with highly processed products containing significantly more particles per gram than minimally processed ones.
But it doesn’t tell the whole story. Researchers also detected microplastics in fresh-caught seafood, indicating that plastic can enter the food supply long before products reach the grocery store.
“It’s tempting to want to draw conclusions like ‘eat less of this and more of that’ to avoid microplastics in your diet; but right now we still know very little about the microplastic burdens in commonly consumed foods,” said Madeleine Milne, lead author of the study.
“Our study adds to this knowledge but also demonstrates the need for further research to better understand the bigger picture, including where these microplastics are coming from and the potential human health risks.”
To get an idea of how much plastic Americans might be consuming, the researchers combined their findings with dietary survey data collected from nearly 2,000 US adults.
They estimated that the average US adult consumes approximately 11,000 microplastic particles annually from the protein products included in their calculations.
But some people could be swallowing a whole lot more than others. Using the highest levels of microplastics found in each protein category, along with average consumption rates, the team estimated that exposure could climb to as much as 3.8 million particles a year.
“This is a startling reminder of just how prolific plastic pollution has become,” said Baechler, who serves as associate director of plastics sciences at Ocean Conservancy.
Microplastics are now widespread throughout the environment, having been detected in the air we breathe, the water we drink and a growing range of everyday products.
These tiny plastic particles, measuring less than 5 millimeters in size, have turned up in human blood, saliva, placentas, testicles, livers, kidneys and even brains, among other organs and tissues.
What happens once they enter the body remains a question of fierce debate. Studies have suggested that microplastics may trigger inflammation, damage cells, disrupt hormones and throw off the balance of bacteria in the gut.
Over time, these effects could take a toll on our health. Researchers have found that they may increase the risk of cardiovascular problems, reproductive issues, neurodegenerative diseases and certain cancers.
