Microplastics have been found in human blood and lungs – should we be worried?

Experts explain what we know so far.
Tuberculosis conceptual illustration.
Tuberculosis, conceptual illustration.ART4STOCK/SCIENCE PHOTO LIBRARY

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.

“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,” says Andrea De Vizcaya-Ruiz, PhD, an associate professor in the department of environmental and occupational health at the University of California, Irvine. 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 fibres, 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. 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 explains. “Microplastics have been found in human saliva, scalp, hair, and faeces, 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 we talked to experts about what we do know.

What are microplastics?

Microplastics are tiny particles of plastic, less than 5mm long, that are created in two ways. Primary microplastics are manufactured to make things like microfibres, 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 year, 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

“Even though microplastics are known to enter the human body, scientists still don’t know how the body processes, metabolises, or eliminates these particles. And the exact dose of microplastics needed to cause disease still remains unknown,” Dr. Johnson-Arbor says. That said, experts have a few concerns about finding microplastics in humans.

For instance, scientists are studying whether microplastics may contribute to inflammation in the digestive system. People with inflammatory bowel disease (IBD) had higher amounts of microplastics in their stool compared to people without IBD, according to a small study of 102 people published in the journal Environmental Science & Technology.

Microplastics can absorb heavy metals and pesticides found in our environment, which we then absorb indirectly, adding another element that needs to be studied. “This could increase our exposure to these chemicals and could lead to poisonous effects,” Dr. Johnson-Arbor says.

Plastics also commonly contain additives like phthalates, which help with flexibility, and Bisphenol-A (BPA), which makes products resilient. Some studies suggest these additives have some effect on our bodies; for example, BPA has been linked to metabolic conditions like type 2 diabetes and cardiovascular disease. However there isn’t enough evidence to say these chemicals are harmful to people in the tiny doses we get from food packages, according to the U.S. Food and Drug Administration.

Can I avoid consuming microplastics?

It’s impossible to avoid them completely (outside of living in a non-plastic bubble!). For any of us to significantly reduce our microplastic exposure, the entire world needs to reduce its reliance on plastics, according to the experts we spoke to.

For that to happen manufacturers would need to drastically change how their products are made. Clothes would need to be produced from organic cotton textiles rather than nylon and other synthetic fibres. Containers and straws would need to be made of alternatives like stainless steel and glass. Shampoo bars would replace liquid shampoo found in plastic bottles. And even if plastic was completely phased out tomorrow, microplastics would still exist. “Since plastic is not easily biodegradable, it’s likely that microplastics will persist in the environment for decades or centuries to come,” Dr. Johnson-Arbor says.

These types of dramatic changes to how much plastic is surrounding us can’t be made on an individual level. But all of us can find ways to use less plastic, which helps reduce the overall amount of microplastics we put out into the world and may even reduce some of your direct exposure too:

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  • Drink tap water over bottled water if possible. Aside from reducing waste, this may help reduce your exposure to microplastics, which have been found in both tap and bottled water, according to the World Health Organization. However, one study found that tap water generally has less microplastic compared to the 11 brands of bottled water tested, according to a 2018 paper published in Frontiers in Chemistry. It’s important to know this isn’t the case for every city in the U.S. as some regions may not have access to clean drinking water. You can check for water quality violations in your area by looking at the Consumer Confidence Report, which is issued annually by the United States Environmental Protection Agency (EPA).
  • Filter your water. Dr. Johnson-Arbor recommends using a product that filters particles smaller than five mm in size. Many products will list the filter’s pore size, which are the holes that the water runs through. This number is commonly measured in micron, which ranges from .05 micron to 5 micron, according to the Centers for Disease Control and Prevention (CDC). (One micron equals .001 millimetres.) “However, even use of a water filter will not eliminate all exposures to microplastics, as they are still present in the air and food,” she says. If you want to be extra diligent, you can buy water filters with glass containers.
  • Wear clothing made from natural textiles. Synthetic fibres such as fleece can shed plastic microfibres when you launder or wear them. Opt for natural fibres like cotton, wool, and linen.
  • Vacuum your home regularly. Microplastics can linger in dust, and vacuuming may cut down on the amount you inhale at home. Look for a vacuum that has a high-efficiency particulate air (HEPA) filter, which can suck up airborne particles with a size of 0.3 micron, according to the EPA.
  • Avoid ordering food that’s served in styrofoam packaging. These containers contain polystyrene, which makes up a large amount of the microplastics found in the oceans. Additionally, research shows that small pieces of take-out food containers can break off and be ingested.
  • Advocate for companies to find plastic alternatives. This could be as simple as asking a local cafe to invest in metal over plastic straws or writing to your local council members asking for initiatives that help reduce plastic use in your region.