Podcast Summary: 3 Takeaways™ with Lynn Thoman
Episode #292 - The Hidden Plastic Inside Us (And Why It’s Rising Fast)
Guest: Dr. Matthew Campen, Toxicologist & Professor, University of New Mexico
Release Date: March 10, 2026

Episode Overview

This episode zooms in on the invisible yet alarming presence of microplastics and nanoplastics inside the human body. Host Lynn Thoman interviews Dr. Matthew Campen, a leading toxicologist whose research is reshaping our understanding of plastic pollution as a public health threat. Key findings include the detection of plastic particles in every human brain tested—especially in dementia patients—and a steep rise in the amount of plastic accumulating in our bodies. The conversation unpacks how plastics enter us, what we know (and don't know) about health risks, what individuals and policymakers can do, and concludes with Dr. Campen’s “three takeaways”.

Key Discussion Points and Insights

What Are Microplastics and Nanoplastics?

• Definition: Macroplastics (large objects) degrade over decades via UV light and oxygen into microplastics (1 micrometer to 5 millimeters), and then into nanoplastics (smaller than cells and even viruses).
  • “...Once they're thrown away, they're going to start degrading...they get smaller and smaller…eventually they become what we call microplastics...then they can break down smaller into the nanoplastic scale, which is now smaller than the cells of your.” (Dr. Campen, 02:04)

Novel Measurement Methods

• New Detection Technology: Dr. Campen's team developed a pyrolysis gas chromatography-mass spectrometry method to detect much smaller particles than conventional microscopy.
• Why It Matters: This method enables evaluation of population-level health associations, not just visual counting.
  • “We needed something that would allow us to look at those nanoscale things...It's sort of a cumulative picture of all the plastic that we can isolate from the body...” (Dr. Campen, 03:07)

Alarming Findings in Human Brains

• Plastic Detected in All Brains Tested: Every human brain sample contained microplastics.
• 50% Increase in Brain Plastic (2016-2024):
  • “...the amount of plastic found in human brains increased by 50% between 2016 and 2024.” (Lynn Thoman, 00:02)
• Up to 10x More Plastic in Dementia Brains: Brains of dementia patients had as much as ten times more plastic than non-demented controls.
  • “Brain tissue from people with dementia contained up to 10 times more plastic than healthy brains...” (Lynn Thoman, 00:02)

Why Is Plastic Accumulating in Brains?

• Sheer Exposure:
  • Plastic production has doubled roughly every 10–15 years since the 1950s.
  • Micro/nanoplastic exposure reflects this exponential growth, with a 30–50 year lag between production and environmental breakdown.
• Vulnerable Organs:
  • The brain is highly metabolically active and receives 30% of the body's blood flow, making it more exposed to circulating particles.
  • Clearance mechanisms in the brain are weaker than those of the liver or kidneys, creating a buildup problem.
    • “The brain has a really bad clearance…that clearance pathway…is not as robust as other organs.” (Dr. Campen, 06:40)

Link to Dementia?

• No proven causal relationship yet.
• Dementia is associated with a leaky blood-brain barrier and impaired clearance, so plastics may accumulate more readily as a result, not a cause.
  • “It's a chicken or egg issue...we're not prone to jumping to the conclusion that plastics cause dementia.” (Dr. Campen, 07:43)

Health Risks – What We Know & Don’t Know

• Plastics are generally “inert” and used safely in medical implants.
• Aged nanoplastics may behave differently—they could aggregate proteins or trigger immune changes, but science is still emerging.
  • “We don't know much…There could be a lot of other immune or biochemical reactions that we just haven't studied yet.” (Dr. Campen, 08:59)

How Are Plastics Getting Inside Us?

• Primary Route: Food
  • Processed meats and foods have the highest levels; unprocessed meats and likely vegetables are lower.
  • “Processed foods, processed meats seem to have the highest amount of plastic...Fresh grass fed beef is relatively quite safe.” (Dr. Campen, 10:21)
• Air and Water?
  • Airborne particles and drinking water are much less significant exposure routes compared to food.

What Can Individuals Do?

• Eat fewer processed meats, more vegetables (as current data suggests lower contamination).
• But Individual Actions Alone Won’t Solve It:
  • Drawing a parallel to the Clean Air Act, Dr. Campen stresses that only large-scale policy can truly move the needle.
    • “That's not how we win environmental problems...there was no individual choice that was going to do anything about it.” (Dr. Campen, 12:04)

Policy Solutions

• Comprehensive Approach Needed:
  • Cap plastic production and use.
  • Revamp real-world recycling, which is shockingly ineffective (“<10% recycled once, <1% twice”).
  • Consider waste-to-energy (incineration) despite controversy—it may be a practical solution to reduce landfilled microplastics and methane generation.
    • “This is not something that individuals can win the day on...It has to be something we address as a nation…” (Dr. Campen, 20:08)

Debunking Misconceptions

• “It's not really coming from the fresh bottles…”
• Plastics in immediate-use products are not the primary concern—it's environmental degradation and accumulation over decades.

Key Takeaways (Three Takeaways Segment – [20:08])

1. Plastic Levels Are Rising—in the environment and in our bodies.
2. Health Risks Unclear…But Worrying Evidence—the coming years of research are critical for clarity.
3. Individual Action Isn’t Enough—comprehensive policy solutions are required to meaningfully address the problem.

Memorable Quotes & Notable Moments

• “We've created a material that never truly disappears. It just gets smaller and smaller until it ends up inside us. What is that doing to our health?”
  — Lynn Thoman ([00:02])

• “The amount of plastics we create doubles every 10 to 15 years or so. So it is an Exponential curve and the delay...means if we figure out plastics are bad for our health, we need to make decisions about plastics policy now to affect our grandchildren.”
  — Dr. Campen ([05:26])

• "This is not an individual choice. Plastic producers have won the argument by making us talk about it like that. It has to be something we address as a nation...”
  — Dr. Campen ([20:08])

• “I try not to panic about these things because I know people really do stress about it and cortisol is bad for your health, you know. So I hope people can make sensible decisions and not panic.”
  — Dr. Campen ([19:20])

Important Timestamps

• Microplastics & Nanoplastics Defined: [02:04]
• New Measurement Methodology: [03:07]
• Finding Plastics in Every Brain Sample: [04:15]
• 50% Increase Over 8 Years: [05:14]
• Why the Brain Has Highest Concentration: [06:40]
• Dementia and Plastics: [07:34]
• What Do Plastics Do in Human Tissue?: [08:59]
• How Plastics Get Into the Body: [10:13]
• Policy vs. Individual Action: [12:04]
• Waste-to-Energy Explained: [14:49]
• Three Takeaways: [20:08]

Closing Thoughts

Dr. Campen reiterates that while the data is concerning, panic is unwarranted. The focus should be on rational, science-based policy solutions—a nationwide effort rather than individual consumer choices. He underscores the need for further research and a balanced, practical approach to polymer pollution and public health risks.

For listeners seeking actionable advice: Focus your concern on reducing processed food intake, favoring whole foods and vegetables. But remember, meaningful change will require much broader societal and legislative efforts.