Microplastics are everywhere, but are they harming us?

By AP Medical Writer Mike Stobb

NEW YORK (AP) — Microplastics are being found in our oceans, air, food and water — and in a wide range of body tissues, including the heart, liver, kidneys and even the testicles.

But are they actually harming you?

The evidence suggests that it might be, but it's limited in scope, and some researchers are concerned but acknowledge that there are many unanswered questions.

Dr. Maria Zlatnik, a San Francisco-based obstetrician-gynecologist who studies environmental toxins and pregnancy, has seen worrying studies about the impact of microplastics on the health of infants and adults.

But it's still an area of ​​nascent research and not something she discusses with patients: “I'm not really sure what to say yet,” Zlatnik says.

Here's what we know so far:

What are microplastics?

Plastic is a man-made material, most of which is made from petroleum and other petroleum products. It can break down into smaller particles when exposed to heat, weather, or by animal digestion.

Researchers are increasingly interested in microplastics, which range in size from the width of a pencil eraser to a fraction of the width of a human hair. Another area of ​​research, nanoplastics, are even smaller.

These tiny plastics have been found in air, water, soil, milk, bottled water, tap water, and in a variety of foods, including salt, sugar, honey, rice, and seafood.

Are there microplastics in your body?

Probably so.

Just how much people inhale and ingest is a matter of scientific debate and can vary depending on what they eat, what they drink and where they live, researchers say.

In 2019, Australian researchers commissioned by the World Wildlife Fund calculated that most people consume about 5 grams of plastic from common foods and drinks each week—the equivalent of one credit card—an estimate that is not widely accepted among researchers but is often featured in news articles.

While researchers are still trying to understand exposure levels, study after study is finding signs of the presence of plastic in body tissues.

“Microplastics have been measured in nearly every body tissue that's been evaluated,” said Tracey Woodruff, a researcher at the University of California, San Francisco. Scientists have also reported finding microplastics in the penis, ovaries and placenta.

Do microplastics harm you?

That is still being sorted out.

A 2022 World Health Organization report concluded that based on the available evidence, there is no clear risk to human health.

And there are no clear signs of a broader public health impact, at least in terms of mortality rates: Deaths from cancer, heart disease and stroke are falling, not rising.

But it was only in recent years that researchers began to measure plastics in the human body and evaluate their health effects, and some of that work is only now coming to fruition.

“Microplastics contain toxic chemicals, so it makes sense they could be harmful,” said Woodruff, who is part of a team that reviewed about 2,000 studies on microplastics at the request of the California State Legislature. He noted that microplastics may, for example, be playing a role in increased incidence of some cancers among young people.

Available information suggests that plastics can cause inflammation and other problematic changes in the body, including increasing the risk of heart attack and stroke.

A small study published in the New England Journal of Medicine earlier this year suggested but didn't prove that patients with traces of plastic in their arteries were at higher risk of dying from heart attack or stroke, but experts not involved in the study suggested the study may have exaggerated the effect.

“There's still a lot we don't know about microplastic particles and the harm they cause to humans, but the information that's currently available is very concerning to me,” said Dr Philip Landrigan of Boston University.

What can be done about microplastics?

The researchers say there are ways to reduce potential exposure to microplastics.

• Take your shoes off before entering your home to avoid bringing plastic-laden dust (not to mention bacteria, dirt, and other debris) into your home.

• Eat home-cooked foods, especially fresh fruits and vegetables.

• “No matter what the instructions on the TV dinner say, you should never microwave meals served on a plastic tray,” Woodruff says.

• Also, opt for reusable stainless steel or glass water bottles instead of disposable plastic ones, she adds.

Zlatnik, the obstetrician, said families with limited income may have bigger concerns.

“I wouldn't advise anyone who is worried about where their next meal is coming from to store leftovers in glass containers or microwave them in plastic containers,” she said.

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Science Education Media Group. The AP is solely responsible for all content.