Microplastics: The Tiny Particles with a Big Health Problem

If you thought plastic pollution was just an environmental issue, buckle up. The science is now very clear: plastic has officially made itself at home inside the human body. And we’re not talking about the occasional rogue water bottle—we’re talking about microplastics, quietly accumulating in our tissues while we go about our lives.

This isn’t fear-mongering. This is published medical science.

What Are Microplastics, Exactly?

Microplastics are plastic particles smaller than 5 millimetres—many are microscopic, some even small enough to enter the bloodstream. They form when larger plastic items break down over time or are intentionally added to products (yes, including cosmetics).

They’re made from polymers like polyethylene, polypropylene and polystyrene and often carry a chemical entourage of additives such as phthalates, bisphenols (think BPA), PFAS, flame retardants and heavy metals—many of which are known endocrine disruptors.

In short: they’re small, persistent, and biologically active. Not exactly house guests you’d invite over.

How Are We Exposed?

Microplastics enter the body primarily through ingestion and inhalation.

• Food & drinks: Microplastics have been detected in drinking water, beer, soft drinks and packaged beverages. In one study, nearly all tested beverages contained measurable microplastic particles.
• Air: Tiny particles (especially those under 2.5 μm) can be inhaled deep into the lungs and pass directly into the bloodstream .
• Personal care products: A 2024 review found microplastics in 16.4% of cosmetic and personal care products, with face scrubs being the worst offenders.
• Translation? You don’t need to live near a landfill to be exposed. Modern life does the job nicely.

Microplastics Don’t Just Pass Through

One of the more unsettling findings from recent research is that microplastics don’t simply exit the body. They accumulate.

They’ve now been detected in:

• Lungs
• Blood
• Liver
• Kidneys
• Heart and blood vessels
• Brain
• Placenta
• Breastmilk
• Ovarian follicular fluid
• Infants’ first stools

Yes—placentas. Microplastics have been found in 100% of placental samples tested in recent years, with concentrations rising significantly over time .

That’s not abstract. That’s next-generation exposure.

What Do Microplastics Do in the Body?

Microplastics aren’t inert passengers. Their irregular surfaces allow them to act like toxic sponges, binding heavy metals, microbes and chemical pollutants, then delivering them straight into human tissues .

Laboratory and animal studies show that microplastic exposure is associated with:

• Increased oxidative stress
• Elevated inflammatory signalling
• Immune system activation
• DNA damage
• Cellular and mitochondrial injury

Liver organoid studies demonstrate measurable hepatotoxicity—even at very low exposure levels—along with disrupted antioxidant balance and increased inflammatory cytokines like IL-6 .

In plain English: these particles stress cells, inflame tissues and interfere with normal biological signalling.

The Emerging Links to Chronic Disease

While observational studies don’t prove causation (science still likes its seatbelts on), the associations are concerning.

• Microplastics have been found in atherosclerotic plaque, with affected patients showing a 4.5-fold increased risk of heart attack, stroke or death during follow-up .
• Post-mortem brain tissue studies show significantly higher microplastic concentrations in people with dementia compared to those without .

Is plastic the new smoking? We’re not there yet—but the trajectory deserves attention.

Why This Matters for Hormones, Fertility and Metabolic Health

Many of the chemicals associated with microplastics are endocrine-disrupting compounds. They interfere with hormone receptors, mimic oestrogen, disrupt thyroid signalling and alter metabolic pathways.

From a functional and hormonal health perspective, this matters because:

• Hormone systems are exquisitely sensitive
• Exposure is chronic, not occasional
• Effects may be subtle but cumulative
• Pregnancy and early development appear particularly vulnerable

Tiny particles. Long-term consequences.

Can We Reduce Exposure?

We can’t live in a plastic-free bubble—but we can be strategic.

Practical steps include:

• Choosing glass or stainless steel for food and drink storage
• Avoiding heating food in plastic
• Filtering drinking water
• Reducing ultra-processed and heavily packaged foods
• Checking personal care products for microplastic ingredients
• Supporting gut, liver and antioxidant pathways (because detoxification is a team sport)

This isn’t about perfection. It’s about reducing the load.

The Take-Home Message

Microplastics are no longer just an environmental concern—they’re a human health issue, with increasing evidence of biological accumulation and potential links to chronic disease.

The research is evolving, but one thing is clear: our bodies were not designed for lifelong exposure to plastic particles and their chemical companions.

Small particles. Big implications. And finally—science is paying attention.

Article Credit

This blog is based on and informed by:
Mahalingaiah S, Nadeau KC, Christiani DC. Microplastics and Human Health. JAMA Insights, December 2, 2025. Published online October 15, 2025.