Microplastic Effects on Human Health

published on 06 March 2024

Microplastics, tiny plastic particles less than 5mm in size, are a growing concern for human health. They enter our bodies through the air we breathe, the water we drink, and the food we eat. Here's a quick overview of what we know about their effects on our health:

  • Primary and Secondary Sources: Microplastics come from larger plastic items breaking down (secondary) or are manufactured small (primary), like in cosmetics.
  • Routes into Our Bodies: We ingest or inhale microplastics through food, water, and air.
  • Health Impacts: They can cause cellular damage, stress bodily systems (digestive, immune, nervous, reproductive, endocrine), and potentially lead to long-term diseases.
  • Knowledge Gaps: There's still much we don't know, including the long-term impacts and the dose-response relationship.

Understanding microplastics and their health risks is crucial for developing strategies to reduce exposure and protect health.

How Do Microplastics Get Into Our Bodies?

Eating and Drinking

The main way microplastics get into us is by eating and drinking things that have them. Seafood like shellfish and small fish eat microplastics from dirty ocean water. Studies say an average person might eat more than 50,000 tiny plastic pieces every year just from seafood.

Drinking water can have microplastics too, coming from things like water treatment plants and plastic bottles. Even though the World Health Organization says it's not proven to hurt us, we still don't know what could happen if we keep drinking them over a long time.

Microplastics can also get into our food from:

  • Salt and beer that use sea water
  • Food boxes and wrappers breaking down
  • Tiny plastic bits added to some foods

Eating is the biggest way we get microplastics into our bodies.

Breathing In

Breathing in microplastics is another way they can get into us. Dust inside our homes and pollution outside can have microplastics.

Research has found tiny plastic fibers from clothes and carpets in the air inside houses. The air outside, especially in cities, has microplastics too. Things like tire dust, road paint, and other city dust can have microplastics that we might breathe in.

The size of the microplastic matters. Smaller pieces can go deeper into our lungs. But we need more studies to really understand what breathing in microplastics does to us.


The tiniest microplastics, called nanoplastics, might be able to get through our skin from products like face scrubs or toothpaste. But, this doesn't happen much because of how big the microplastics are.

We need more research to see if touching microplastics can really harm us, but it seems like eating and breathing them in is a bigger worry.

Toxic Effects of Microplastics

Microplastics, those tiny plastic bits, can be harmful to our health in different ways. Let's break down what the latest studies say about how they might affect us:

Effects on Cellular Structures

  • Microplastics can rough up the outside of our cells and mess with important cell parts.
  • They can get inside cells and pile up, causing trouble and even spreading to other cell areas.
  • These plastics can stress our cells out, leading to damage, especially in the mitochondria, which are like the powerhouses of our cells.
  • They can also mess with our DNA and the inside workings of our cells.

Effects on Bodily Systems

Digestive System

  • When we eat microplastics, they can stick around in our guts, hurt our stomach lining, throw off our gut bacteria, and block digestive enzymes.
  • They can move from our guts to other body parts, causing inflammation and stress.

Immune System

  • Microplastics can make our immune system go haywire, causing inflammation and making it harder for our bodies to fight off other problems.

Nervous System

  • They can mess with the chemicals in our brains, leading to changes in behavior and harming brain development.

Reproductive System

  • There's evidence that microplastics can harm fertility, pregnancy, and even affect babies.

Endocrine System

  • These tiny plastics might mess with our hormones, but scientists are still figuring this out.

Toxic Effects in Humans

Even though a lot of what we know comes from studying cells and animals, there's growing proof that microplastics can hurt humans too:

  • People have microplastics in their poop, showing we're eating them. This might be linked to gut diseases.
  • They've been found in lung tissue and even in the placenta, which means they can get to very sensitive places inside us.
  • There's some evidence linking microplastics to problems like immune system issues, metabolic trouble, breathing problems, and even cancer, but more research is needed.

In short, microplastics seem to be bad news for our health, affecting us in many ways. As scientists learn more, they're getting a clearer picture of how these tiny pollutants might be making us sick and what we can do about it.


Knowledge Gaps

Even though we've learned a lot about microplastics and how they might affect our health, there's still a lot we don't know. Here are some big questions we're still trying to answer:

Long-Term Impacts

  • Most of what we know comes from short studies. We're not sure what happens if you're around microplastics for a long time, like months or years.
  • We don't know if our bodies hold onto microplastics or get rid of them. If they stick around, could they make us sicker?

Dose-Response Relationships

  • We're still figuring out how the amount and size of microplastics we're exposed to relates to how sick they can make us. When do they start to become a problem?
  • We need more info on whether being around more microplastics makes us sicker in a straight-forward way or if it suddenly gets much worse.

Human Epidemiological Evidence

  • Right now, a lot of what we think we know about microplastics and health comes from animal studies and tests on cells. We need to study people over time to really understand the risks.
  • Studies that watch people for a long time, seeing who gets exposed to microplastics and who gets sick, could help us connect the dots better.

Mechanisms of Harm

  • We're still not sure exactly how microplastics make us sick. This makes it hard to figure out how to protect ourselves or fix the problem.
  • We need to dive deeper into how microplastics might cause stress inside our bodies, mess with our hormones, damage our DNA, or cause inflammation.

Filling in these gaps will help us understand just how risky microplastics are. As scientists get better at studying these tiny plastics, they might come up with new ways to test for them, understand the data from animal studies better, and find out how to keep us safer from their effects.


Microplastics are tiny plastic pieces that have spread all over the place, even to the most remote areas. This means we're all exposed to them through the air, water, food, and everyday products.

The science on how microplastics affect our health is still pretty new, but early studies suggest we should be worried. These studies have shown that microplastics can cause stress to our cells, inflammation, damage to our organs, and other harmful effects if we eat or breathe them in.

Researchers have also found signs that being around microplastics might increase the risk of getting long-term diseases. And they've found microplastics in places inside us where they really shouldn't be, like in lung tissue, poop, and even the placenta.

But, there's a lot we still don't know, like:

  • How being exposed to microplastics for a long time, like months or years, affects us. Short studies don't tell us everything.
  • We're not sure how much exposure is too much before health problems start to show up.
  • We need more studies on people to confirm what we've learned from animal and cell studies.
  • We don't fully understand how microplastics cause harm inside our bodies, which makes it hard to figure out how to protect ourselves or fix any health issues.

It's really important that we do more research on this. As microplastic pollution keeps growing, we need to understand the risks better. Knowing more about how microplastics harm us can help make policies and actions to reduce our exposure, especially for people who are more at risk like kids or pregnant women.

While we can try to reduce our own use of microplastics, the biggest changes need to come from big actions by communities, countries, and the whole world to cut down on plastic waste and keep an eye on our health and the environment. But to make these changes, we first need to invest in understanding the link between microplastics and health problems. The health of people and the planet might depend on figuring this out and moving towards a future with less plastic.

How do microplastics affect humans health?

Microplastics can get into our bodies through the food we eat, the water we drink, and the air. Once inside, they might cause swelling, damage our cells, mess with our hormones, and lead to other health problems. We still need to learn more about how microplastics affect us over time. It's a good idea to try and avoid them when we can.

What are 5 harmful effects of plastic?

Five main ways plastic hurts the environment:

  • It can kill sea animals and birds when they get tangled in it or eat it
  • Land animals can also die from eating plastic
  • Plastic takes up space in landfills and natural areas
  • Making and getting rid of plastic creates harmful chemicals
  • As plastic breaks down, it turns into microplastics that spread in water and soil

Do microplastics ever leave your body?

We're not sure if microplastics can leave our bodies after we swallow or breathe them in. More studies are needed. Some tiny plastic pieces might stay in our organs or tissues forever. The smaller the piece, the easier it might get into cells and stay there.

What are the two big problems with microplastics?

The two main issues with microplastics are:

  • They're all over our oceans and harm sea life
  • They might hurt us if we eat or breathe them in by causing physical damage or toxic effects

We really need to do more research to understand these risks better. Cutting down on plastic waste is crucial to deal with this problem.

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