#332 - AMA #67: Microplastics, PFAS, and phthalates: understanding health risks and a framework for minimizing exposure and mitigating risk

Jan 20, 2025 Episode Page ↗
Overview

Peter Attia, MD, introduces an AMA episode (AMA #67) focusing on microplastics and associated chemicals like BPAs, PFAS, and phthalates. He discusses their ubiquity, human exposure routes, and the challenges in understanding their health impacts, aiming to provide a framework for risk reduction.

At a Glance
3 Insights
25m 21s Duration
7 Topics
6 Concepts

Deep Dive Analysis

Introduction to Microplastics and Associated Chemicals

The Challenge of Analyzing Microplastics and Chemicals

Defining Microplastics, Nanoplastics, BPA, PM2.5, and Phthalates

Reasons for Increased Microplastic Prevalence and Research

Human Exposure Pathways to Microplastics and Nanoplastics

Quantifying Human Microplastic Consumption

How the Body Eliminates Absorbed Microplastics

Microplastics

Plastic particles typically defined as smaller than five millimeters, though current studies often focus on those smaller than one millimeter. They are completely ubiquitous, found in water, food, air, and living organisms.

Nanoplastics

Plastic particles that are smaller than one micrometer (one one-thousandth of a millimeter). These are of particular concern due to their minute size, which allows for potential absorption into the body.

BPA (Bisphenol A)

A chemical historically used to make hard polycarbonate plastics, epoxies, and resins. While its active use has been reduced, it's often replaced by other bisphenols like BPS and BPF, whose safety is not yet fully clear.

PM2.5

Particulate matter in the air smaller than 2.5 micrometers. Particles of this size, if inhaled, have the potential to become systemic by crossing the lung's epithelial barrier and entering the bloodstream. Most PM2.5 is not microplastic, primarily originating from air pollution sources like fires and fossil fuel combustion.

Phthalates

A class of chemicals used in plastics to increase flexibility and found in personal care products like shampoos, lotions, and laundry detergents to make fragrances last longer. Their use is still allowed in food contact applications and personal care products, though some companies have voluntarily reduced their use.

Epithelial Barrier

The protective layer of cells on the surface of the body (skin) and lining internal organs (like the gut and lungs). This barrier is the body's first line of defense against microplastics, preventing larger particles from entering the body.

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What are microplastics and related chemicals?

Microplastics are plastic particles smaller than 5 millimeters, with nanoplastics being even smaller (<1 micrometer). Related chemicals include BPA (used in hard plastics), PM2.5 (airborne particulate matter <2.5 micrometers), and phthalates (used to make plastics flexible and in personal care products).

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Why are microplastics a growing concern now?

The proliferation of plastics since the 1950s has led to their accumulation in the environment, and there's also been a significant increase in scientific research and public attention focused on detecting and studying them.

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How are humans exposed to microplastics and nanoplastics?

Humans are primarily exposed through inhaling plastic dust and fibers, and by consuming food and beverages such as seafood, salts, water (tap and bottled), fruits, vegetables, meats, milk, beer, and wine.

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How much plastic do humans consume weekly?

While highly variable, estimates suggest humans consume between 10 and 300 micrograms of micro-nanoplastics per week. The widely circulated claim of consuming a 'credit card's worth' (5 grams) of plastic per week has been largely debunked.

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How does the human body eliminate microplastics?

The body primarily eliminates microplastics through coughing, sneezing, urine, and stool. Larger particles (>10 microns) are removed efficiently, with about 99% of ingested microplastics being eliminated via stool within 24 to 72 hours.

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What size microplastics can be absorbed into the body?

Particles smaller than 2.5 micrometers can be absorbed through both the lungs and the gut. In the gut, particles up to 10 micrometers are practically absorbed, though theoretically, the gut lining could absorb particles as large as 150 micrometers.

1. Use Non-Plastic Drinkware

Consider using non-plastic containers, such as a metal camping coffee cup, for beverages. This practice is implicitly endorsed as a way to avoid plastic exposure, especially when discussing microplastics and related chemicals.

2. Access Full AMA Episodes

Become a premium member to hear the complete version of AMA episodes, which offer detailed responses to subscriber questions and in-depth clarity on topics of special interest.

3. Connect on Social Media

Find Peter Attia on YouTube, Instagram, and Twitter using the handle @peterattiamd to engage with additional content and updates.

If you are listening to this thinking that there is a punchline and a one-word answer, I'm going to spare you the disappointment. This is a very nuanced topic.

Peter Attia

This has been a royal pain in the ass to prepare for.

Peter Attia

Further from the shore, the deeper the water.

Nick

A lie will travel around the world or halfway around the world before the truth has a chance to pull its boots on.

Peter Attia
<5 millimeters
Microplastic definition (typical) Current studies often focus on particles smaller than 1 millimeter.
<1 micrometer
Nanoplastic definition One one-thousandth of a meter.
<2.5 micrometers
PM2.5 definition Refers to particulate matters in the air that are smaller than this size.
A few percent
PM2.5 contribution from microplastics Most PM2.5 comes from air pollution like fires and fossil fuels.
<2.5 microns
Pulmonary epithelium absorption threshold For particles to become systemic if inhaled.
<10 microns
GI epithelium absorption threshold (practical) For microplastics to be absorbed across the gut lining.
Up to 150 microns
GI epithelium absorption threshold (theoretical) For microplastics to be absorbed across the gut lining.
10 to 300 micrograms/week
Estimated weekly human microplastic consumption (broad range) Highly variable based on geography, food, and water source.
~4 micrograms/week
Estimated weekly human microplastic consumption (2021 study) From fish, water, beer; likely an underestimate as it didn't include all sources.
140 to 310 micrograms/week
Estimated weekly human microplastic consumption (2023 Korean study) A narrower band, largely consistent with the upper limit of US-based studies.
5 grams/week
Debunked weekly human microplastic consumption Refers to the 'credit card worth of plastic' claim, which has been largely debunked.
~99%
Ingested microplastics eliminated via stool Occurs within a relatively short transit time of 24 to 72 hours.
0.3% to 1.7%
Microplastics absorbed across GI epithelium (animal studies) Absorption capacity is heavily size-dependent.