#332 - AMA #67: Microplastics, PFAS, and phthalates: understanding health risks and a framework for minimizing exposure and mitigating risk
In this episode of The Peter Attia Drive, the discussion focuses on the presence and potential health risks of microplastics, chemicals like BPA and phthalates, and particulate matter (PM 2.5) in our environment and diet. The podcast explores the prevalence of these substances, their sources, and the various pathways by which humans are exposed to and ingest them.
Additionally, the episode delves into the current research on quantifying the average levels of microplastic consumption and the extent to which these particles may be absorbed by the human body. While acknowledging the uncertainties and need for further data, the discussion provides a framework for understanding and mitigating potential risks associated with exposure to these substances.
This is a preview of the Shortform summary of the Jan 20, 2025 episode of the The Peter Attia Drive
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1-Page Summary
Defining Microplastics, Chemicals, and PM 2.5
Microplastics are plastic particles smaller than 5mm, according to the AMA episode. Sanger-Katz notes they are ubiquitous in water, food, air, and the environment.
BPA makes plastics hard while phthalates increase flexibility. Sanger-Katz explains BPA usage has declined, replaced by BPS and BPF variants, though phthalates remain prevalent in personal care products -- a key human exposure source.
PM 2.5 refers to particulate matter under 2.5 micrometers that can enter the bloodstream via inhalation, Barbaro and Sanger-Katz state. Unlike microplastics, PM 2.5 originates from burning fuels like wood and coal.
Why Microplastics Seem More Prevalent
Sanger-Katz attributes the rise of microplastics to plastics' proliferation since the 1950s and increased scientific efforts to detect them in environmental and dietary sources. However, she notes more data is needed to determine if increased detection or genuine accumulation is driving perceived increases.
Human Exposure and Ingestion of Microplastics
Humans ingest microplastics through food and beverages like seafood, produce, meats, dairy, beer and wine, Sanger-Katz states. Inhalation of microplastic dust and fibers is another common exposure route. Smaller nanoparticles are absorbed more readily, moving up food chains to magnify exposure.
Quantifying Human Plastic Consumption
While earlier claims of consuming 5g of plastic weekly were debunked as exaggerations, Sanger-Katz cites 2021 research estimating average microplastic ingestion at 4 micrograms per week and 2023 Korean studies suggesting 140-310 micrograms weekly -- highlighting uncertainty.
Chemicals Not Eliminated From the Body
Sanger-Katz states 99% of ingested microplastics are eliminated via stool within 24-72 hours. However, animal studies suggest 0.3-1.7% may cross the GI barrier. Particles under 10 micrometers pose absorption risks via inhalation and digestion, underscoring needs for exposure reduction strategies.
1-Page Summary
Additional Materials
Clarifications
- BPA, BPS, and BPF are chemicals used in plastics as alternatives to Bisphenol A (BPA). BPA is known for making plastics hard, while phthalates increase their flexibility. Phthalates are still commonly found in personal care products, serving as a significant source of human exposure to these chemicals.
- PM 2.5 stands for particulate matter that is 2.5 micrometers in size or smaller. These particles can come from various sources, including burning fuels like wood and coal. PM 2.5 can enter the bloodstream through inhalation and is a significant component of air pollution.
- Human exposure to microplastics occurs through ingestion of contaminated food and beverages like seafood, produce, meats, dairy, beer, and wine. Additionally, inhalation of microplastic dust and fibers is a common exposure route. Smaller nanoparticles are absorbed more readily, increasing exposure levels as they move up the food chain. Understanding these pathways is crucial for assessing the potential health impacts of microplastic exposure on humans.
- Nanoparticles, due to their extremely small size, can be easily absorbed by organisms and move up the food chain, increasing the likelihood of exposure to microplastics. This magnification effect occurs as smaller particles are more readily taken up by organisms and can accumulate in higher concentrations as they progress through the food web. The smaller the particle, the easier it is for organisms to absorb them, leading to potential bioaccumulation and increased exposure to microplastics. This phenomenon highlights the importance of understanding the impact of nanoplastics on ecosystems and human health.
- The varying estimates of microplastic ingestion stem from different research methodologies and sample populations, leading to a range of results. Factors such as diet, lifestyle, and geographic location can influence the amount of microplastics a person may ingest. These estimates highlight the complexity of assessing human exposure to microplastics and the need for further research to better understand the extent of this issue. The discrepancies in the estimates underscore the ongoing scientific efforts to quantify and evaluate the impact of microplastic consumption on human health.
- Microplastics that are ingested are mostly eliminated from the body through stool within 24-72 hours. However, a small percentage (0.3-1.7%) of ingested microplastics may potentially cross the gastrointestinal barrier and enter the bloodstream. Particles smaller than 10 micrometers pose risks of being absorbed through inhalation and digestion, emphasizing the importance of strategies to reduce exposure to microplastics.
Counterarguments
- While BPA usage has declined, the safety of BPS and BPF as replacements is still under scrutiny, and some research suggests they may have similar endocrine-disrupting effects.
- The assertion that 99% of ingested microplastics are eliminated might be overly simplistic, as it does not account for the potential bioaccumulation of microplastics or their additives in the body over time.
- The estimates of microplastic ingestion vary widely, indicating a need for more standardized methods of measurement and analysis to provide more accurate and consistent data.
- The focus on microplastics might overshadow other environmental and health concerns related to plastic pollution, such as the effects of larger plastic debris on wildlife and ecosystems.
- The impact of microplastics on human health is still not fully understood, and more research is needed to assess the long-term effects of chronic exposure.
- The emphasis on reducing exposure to microplastics could divert attention from the need to address the root causes of plastic pollution, such as overproduction and inadequate waste management.
- The comparison between microplastics and PM 2.5 might be misleading, as they are different pollutants with different sources and health impacts, and strategies to address them might also differ.
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Defining Microplastics, Bpas, Phthalates, and Pm 2.5
The AMA episode unpacks the complex world of microplastics, BPAs, phthalates, and PM 2.5, shedding light on their definitions, sources, and impacts.
Microplastics Are Plastic Particles Smaller Than 5 Millimeters
Mnps Are in Water, Food, Air, and the Environment
Microplastics are generally defined as plastic particles smaller than five millimeters, and they are present in water, food, air, and the environment. However, current studies classify microplastics as those smaller than one millimeter. Nanoplastics, on the other hand, are particles that are even smaller, measuring less than one micrometer.
Bpas Make Plastics Hard, Phthalates Make Plastics Flexible
Bisphenol Chemicals (Bpa): Reduced, Replaced by Variants
Bisphenol A, commonly known as BPA, has seen decreased usage in the past fifteen years and is often replaced by other bisphenols such as BPS and BPF. BPA is traditionally used to produce polycarbonate plastic, which is used in manufacturing hard plastics like those found in water bottles and certain resins.
Phthalates in Personal Care Products Lead To Significant Human Exposure
Phthalates are added to plastics to increase their flexibility and durability. They're also commonly found in personal care products such as shampoos, lotions, and laundry detergents to preserve the scent of fragrances. The usage of phthalates in personal care products remains permitted, and this is identified as a significan ...
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Defining Microplastics, Bpas, Phthalates, and Pm 2.5
Additional Materials
Clarifications
- Nanoplastics are plastic particles smaller than one micrometer, even tinier than microplastics. They can result from the breakdown of larger plastic items or be intentionally manufactured. Nanoplastics can pose unique challenges due to their size and potential to interact with biological systems.
- Bisphenol A (BPA) is a chemical traditionally used in making hard plastics. Due to concerns about its potential health effects, BPA has been replaced by variants like BPS and BPF in many products. These variants serve similar purposes in manufacturing but are chosen as alternatives to address the perceived risks associated with BPA.
- Phthalates are chemicals added to plastics to enhance flexibility and durability. They are also commonly used in personal care products like shampoos, lotions, and laundry detergents to help preserve fragrances. The presence of phthalates in personal care items can lead to significant human exposure to these chemicals. Despite concerns ...
Counterarguments
- While the text states that microplastics are defined as smaller than five millimeters, it is important to note that the definition can vary, and some organizations or studies may use different size ranges to define microplastics.
- The text implies a clear distinction between microplastics and nanoplastics based on size, but in reality, the transition between these categories can be fluid, and the impact of nanoplastics is still an emerging area of research.
- The mention of BPA being replaced by BPS and BPF does not address the concern that these substitutes may also have similar or new health and environmental risks, which is an area of ongoing research.
- The text states that phthalates are significant due to their presence in personal care products, but it does not mention that they are also found in a wide range of other consumer products, including children's toys, medical devices, and food packaging, which also contribute to human exposure.
- The text could be interpreted as suggesting that natural gas combustion i ...
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Why Microplastics and Chemicals Seem More Prevalent Now
As conversations around microplastics and related chemicals multiply, understanding why these substances seem more prevalent is essential.
Plastics Proliferation Drives Microplastic Rise
Scientific Drive to Detect and Measure Environmental and Human-Consumed Microplastics Due to Plastics' Ubiquity
Since plastics weren't widely used until after the 1950s, their proliferation over the past 70 years has led to the rise of microplastics. Plastics break down into smaller and smaller pieces, resulting in microplastics that spread into various ecosystems. There has been an increase in scientific studies focusing on microplastics, reflecting the urgent need to understand the presence and impact of these tiny particles in both environmental and human contexts due to the now ubiquitous nature of plastics.
Microplastic Increase May Reflect Detection Efforts More Than Actual Rise
Need More Data to Assess Microplastic Increase: Accumulation Trend or Improved Detection?
The perceived increase in microplastics may be a result of better and more conce ...
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Why Microplastics and Chemicals Seem More Prevalent Now
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Clarifications
- Microplastics are harmful as they can absorb and concentrate toxic chemicals, posing risks to marine life and potentially entering the food chain. Their small size allows them to be ingested by a wide range of organisms, leading to various health and ecological impacts. The concern arises from their persistence in the environment, difficulty in removal, and the potential long-term consequences on ecosystems and human health. Understanding and mitigating the presence of microplastics is crucial for safeguarding biodiversity and ecosystem health.
- Microplastics are detected and measured through various scientific methods such as microscopy, spectroscopy, and chemical analysis. Researchers collect samples from different environments like water bodies, soil, and air, and then analyze these samples in laboratories to identify and quantify the presence of microplastics. Detection techniques can involve visual identification of particles, use of specialized equipment to measure particle size and composition, and even molecular techniques to trace the origin of microplastics. The goal is to understand the distribution, abundance, and potential impacts of microplastics in ecosystems and human health.
- The distinction between ge ...
Counterarguments
- The proliferation of plastics might not be the only factor leading to the rise of microplastics; other factors such as changes in waste management practices or environmental conditions could also contribute.
- While plastics do break down into microplastics, the rate and extent of this process can vary greatly depending on environmental conditions, and not all plastics may contribute equally to the problem.
- The urgency in scientific studies might not only stem from the ubiquity of plastics but also from increased public awareness and concern, which can drive research funding and interest.
- Improved detection efforts could be revealing a problem that has been present but unnoticed for a long time, suggesting that the actual rise in microplastics might still ...
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Exposure and Ingestion of Chemicals by Humans
The conversation focuses on examining the various ways humans are exposed to and ingest microplastics and chemicals, emphasizing both known and unknown aspects of the issue.
Human Exposure to Microplastics and Chemicals: Inhalation and Consumption
Micro-nano particles (MNPs) are omnipresent in the environment—found in water, food, and air—and consequently, humans are exposed to them through both consumption and inhalation. The most common routes of human exposure to microplastics stem from inhaling plastic dust and fibers and from consuming food and beverages that contain micro-nano plastics (MNPs).
Foods and beverages that are of concern because they may contain MNPs include seafood, salts, water (including tap and bottled), fruits, vegetables, meats, milk, beer, and wine. The presence of NMPs is concerning due to their presence in water, which is subsequently consumed by both sea life and terrestrial animals, as well as humans, in various forms.
Eating a piece of plastic that is five millimeters in size is not worrisome because such large pieces are not absorbed by the body and are simply excreted.
Microplastics Accumulate, Moving Up Food Chain To Human Exposure
Nano plastics in soil can be taken up by plants, which then become part of the food chain, magnifying exposure risks at higher levels, including in both seafood and land animals. These magnified exposures underline the growing need fo ...
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Exposure and Ingestion of Chemicals by Humans
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Clarifications
- Micro-nano particles (MNPs) are extremely small particles that measure in the nanometer range, making them invisible to the naked eye. These particles are prevalent in the environment due to various sources like plastic degradation, industrial processes, and natural phenomena. MNPs can be found in water bodies, soil, air, and even in living organisms, contributing to their widespread presence in the environment. The small size of MNPs allows them to disperse easily and be ingested or inhaled by humans and other organisms, raising concerns about their potential impacts on health and ecosystems.
- Micro-nano particles (MNPs) from soil can be absorbed by plants. When animals eat these plants, they ingest the MNPs, which then accumulate in their bodies. As animals higher up the food chain consume these contaminated animals, the MNPs move up the food chain, ultimately reaching humans through the consumption of seafood and land animals.
- The foods and beverages that may contain micro-nano plastics include seafood, salts, water (tap and bottled), fruits, vegetables, meats, milk, beer, and wine. These items are of concern due to the potential presence of micro-nano plastics, which can be ingested by humans through consumption.
- Exposure to microplastics and associated chemicals over time can lead to potentia ...
Counterarguments
- While the text suggests that ingesting a five-millimeter piece of plastic is not worrisome, it does not address the potential for physical harm or obstruction that larger pieces of plastic might cause, especially in children or wildlife.
- The assertion that nano plastics in soil can be taken up by plants and enter the food chain, thereby increasing exposure risks, may be overly simplistic as it does not consider the complex interactions in soil ecosystems or the varying ability of different plants to absorb and translocate nano plastics.
- The text calls for public awareness and more research on the effects of micro-nano plastics on human health, but it does not acknowledge the current efforts and advancements already being made in this field.
- The statement that particles smaller than 2.5 microns can be absorbed by the pulmonary epithelium and that the gut can absorb particles up to 150 microns in size may be misleading, as it oversimplifies the complex mechanisms of particle absorption and does not consider other factors such as particle shape, charge, or chemical composition.
- The text im ...
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Quantifying the Amount of Plastic Humans Consume
Recent discussions and research aim to provide clarity on how much microplastic humans ingest and whether earlier sensational claims about plastic consumption are accurate.
Microplastic and Chemical Intake: 10-300 Micrograms Weekly
Individuals are exposed to microplastics primarily through their diet and environment, with an estimated consumption ranging from 10 to 300 micrograms per week. Geography, food sources, and drinking water sources are key determinants in the levels of exposure one might experience.
4 Micrograms/Week Average Consumption (2021 Study)
A study in 2021 reported that on average, humans might ingest about four micrograms of microplastics per week—a figure derived from common consumables like fish, crustaceans, mollusks, tap and bottled water, and beer. However, this number might not capture the full scope of microplastic ingestion as it did not account for all possible sources.
2023 Study: Estimate 140-310 Micrograms/Week
In contrast to the earlier study, research from 2023 conducted in Korea points towards a higher ingestion rate, estimating that the weekly microplastic intake for humans ranges between 140 and 310 ...
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Quantifying the Amount of Plastic Humans Consume
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Counterarguments
- The range of 10-300 micrograms of microplastics ingested weekly is quite broad, which may indicate a lack of precision in the current understanding of microplastic consumption.
- The 2021 study's average of 4 micrograms per week may not be representative of the global population, as dietary habits and environmental exposure to microplastics can vary significantly.
- The 2023 study's estimate of 140-310 micrograms may still not account for all sources of microplastics, such as air and dust, which could mean actual intake is higher.
- ...
Actionables
- You can reduce your microplastic intake by choosing glass or stainless steel containers over plastic for food storage and drinking water. Since microplastics can leach from plastic containers, especially when they are heated or scratched, opting for alternatives can minimize your exposure. For example, use glass jars to store leftovers and carry a stainless steel water bottle instead of buying bottled water.
- Start a weekly meal plan that prioritizes fresh, unpackaged foods to cut down on microplastic consumption. Processed and packaged foods often contain higher levels of microplastics due to the packaging and manufacturing processes. By planning meals around fresh produce, bulk grains, and unpackaged meats, you not only reduce plastic waste but also potentially lower the microplastics you ingest. Visit local farmers' markets or choose loose produce at the store, and use cloth bags for transport.
- Implement a home water filtration system that targ ...
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Examining Chemicals Not Eliminated From the Body
The conversation reviews the potential health impacts of microplastics and other chemicals not fully eliminated from the body, and presents strategies for minimizing exposure.
99% of Ingested Microplastics Are Eliminated Through Stool Within 24 to 72 Hours
Research indicates that the vast majority of ingested microplastics are expelled from the body through the stool. Typically, this elimination occurs within a timeframe of 24 to 72 hours following ingestion.
Fraction of Microplastics Absorbed Across Gastrointestinal Epithelium
Despite the efficient elimination through stool, a small portion of microplastics has the potential to cross the gastrointestinal (GI) epithelium. Animal studies have estimated that about 0.3% to 1.7% of microplastics could be absorbed across the GI epithelial barrier into the body. The rate of absorption is dependent on the size of the particles, with smaller particles having a higher likelihood of passing through this barrier.
Particles <10 Micrometers May Be Absorbed and Reach the Body Through Inhalation
Particles that measure less than 10 micrometers are of particular concern, as these can be small enough to be inhaled into t ...
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Examining Chemicals Not Eliminated From the Body
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Clarifications
- The gastrointestinal epithelium is a single cell layer lining the intestines, responsible for absorption and secretion. It plays a crucial role in allowing beneficial substances to enter the body while preventing harmful substances from doing so. Various cell types within this epithelium contribute to its functions, such as enterocytes and goblet cells.
- The absorption rate of microplastics across the gastrointestinal epithelium varies based on the size of the particles. Smaller particles have a higher likelihood of being absorbed into the body compared to larger ones. This is because smaller particles can more easily pass through the epithelial barrier. Understanding this relationship helps assess the potential health risks associated with microplastic exposure.
- Microplastics, particularly those smaller than 10 micrometers, can be absorbed into the body through ingestion or inhalation. Once inside the body, these particles may accumulate in various bodily tissues over time. The concern lies in the potential long-term health effects of this accumulation, as the presence of microplastics and associated chemicals in tissues could lead to adverse health outcomes. Researchers are studying the risks associated with the accumulation of microplastics ...
Counterarguments
- The elimination rate of microplastics may vary based on individual health, diet, and the specific type of plastic ingested, suggesting that the 24 to 72-hour window might not be accurate for all cases.
- The absorption rates provided from animal studies may not directly translate to humans due to physiological differences, and more human-specific research is needed.
- The impact of microplastics smaller than 10 micrometers might be overstated if the body has efficient mechanisms to deal with such particles, which is not fully understood yet.
- The long-term health effects of microplastics are still not well-established, and there may be a tendency to overstate the risks without sufficient longitudinal studies.
- While reducing exposure ...
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