Microplastics Have Been Found in Human Blood and Lungs—Should We Be Worried?

The majority of us don’t purposefully eat plastic, but that doesn’t mean we’re not consuming it every day. Microplastics, which are tiny plastic fragments, are everywhere—including inside of our bodies, according to mounting research. For the first time, researchers found that 17 out of 22 people had microplastics originating from common products in their blood, according to a May 2021 paper published in the journal Environment International.¹

“This is the first study to identify plastics that we know are in containers, plastic bottles, clothing, and other products that we use, inside of people,” Andrea De Vizcaya-Ruiz, PhD, an associate professor in the department of environmental and occupational health at the University of California, Irvine, tells SELF. The two most common types of plastic found in the study were polyethylene terephthalate (PET), which is used to make plastic water bottles and clothing fibers, and polystyrene, which is found in food packaging, disposable utensils, and straws.

In March 2022, researchers published a paper with another original discovery: 11 out of 13 people had microplastics in their lungs, according to the study published in The Science of the Total Environment.² Numerous other studies support that we’re regularly consuming plastic, Kelly Johnson-Arbor, MD, a medical toxicologist at MedStar Health in Washington, D.C., and co-medical director at the National Capital Poison Center, tells SELF. “Microplastics have been found in human saliva, scalp hair, and feces, suggesting that we are all likely exposed to these plastic fragments on a regular basis,” she says.

Researchers are still exploring what this means for human health, but SELF talked to experts about what we do know.

What are microplastics?

Microplastics are tiny particles of plastic, less than 5 mm long, that are created in two ways. Primary microplastics³ are manufactured to make things like microfibers⁴, which are found in synthetic fabrics, or plastic microbeads, which are in some cosmetics. Secondary microplastics are formed after breaking off from larger plastic products like water bottles, car parts, and product packaging.

A biodegradable item such as a banana naturally breaks down until it finally dissolves. But many plastics never decompose completely. They get smaller and smaller over time, but the pieces remain in our environments as pollution for hundreds of years, resulting in secondary microplastics, Dr. De Vizcaya-Ruiz says.

Okay, but why are microplastics inside our bodies?

Microplastics can be found in our water, air, food, and soil, so they’re unavoidable.

“When humans consume food, drink water, or breathe air that is contaminated with microplastics, the plastic fragments can enter the body,” Dr. Johnson-Arbor says. Some estimates show that people in the U.S. consume and breathe in between 74,000 and 121,000 microplastic fragments each year⁵, according to Dr. Johnson-Arbor.

But how exactly do these plastics get into our blood? After consuming food or water containing microplastics, researchers suspect those tiny particles make their way to the gut, through the intestinal membrane, and into the bloodstream, Dr. De Vizcaya-Ruiz says. Something similar may happen when microplastics enter the bloodstream after being inhaled and passing through the membrane of the lungs.

How are microplastics affecting human health?

Plastic may be ubiquitous now, but it’s only been widely used for the past 70 years or so, meaning there aren’t a lot of studies examining what types of plastics may affect human health and in what quantities.⁶