The way our body ingests and inhales microplastics, and how the nano particles affect our overall health, are the predominant focal points of Dr. Kari Nadeau and her lab, the Allergy, Extreme Weather, and Exposomics Lab at the Harvard Chan School of Public Health. Using a laser-guided infrared system, the lab is measuring the level of microplastics (and other toxins) in a patient’s body from just two drops of their blood.
Research shows that increased levels of microplastics may heighten the risk for stroke, dementia, and heart attacks. And Dr. Nadeau, Harvard’s Chair of the Department of Environmental Health, believes gathering insight into this data is critical today.
“We can measure, we can monitor, and then we can manage,” she says.
The DOC community interacted with Dr. Nadeau and her lab’s technologies at DOC 2025’s Living Room Lab, while you can hear more from her “Blood (Proteomics), Breath and Microplastics” presentation in the video or read our lightly edited transcript below.
TRANSCRIPT:
Dr. Kari Nadeau
Thank you. It’s great to be here. I’m excited to talk to you about something that’s on many people’s minds today. But importantly, it’s also in your mind and I’ll talk about that. So we are in an era called the Pleistocene era. This is taken from Texas, where one of their floods deposited a lot of plastic in one particular layer. This is not just in Texas. This is in many parts of the US as well as the world. That plastic will probably last for thousands of years. You see this embedded in the Earth. Unfortunately, plastics are also embedded in our body. With that in mind, how do they get into our body? Well, microplastics versus nanoparticles are important because size matters.
Anything less than about a millimeter is called a microplastic. Anything that’s less than about a micrometer is called a nano plastic. Why is that important to you? Because these can be absorbed through the skin. They can be absorbed through the gut, they can be inhaled as well. That’s a problem in terms of overload of plastics in our bodies. This is just what we breathe in. For example, how many of you heard that you eat about a credit card’s worth of plastic a week? In Indonesia, it’s about a day, but that’s just eating. That’s just through our gut. This is inhaling. I’ll talk about this as well. But we have about over a year. The height of two giraffes over a lifetime, potentially the height of the Eiffel Tower. In places like Indonesia, the height of a mountain. When we think about what we’re doing and how we’re getting exposed to microplastics in nano plastics, it’s through bottled water. Water that’s in bottles that are plastic. It’s through beer. It’s through air. You notice I didn’t put wine on this list. We don’t know that data yet. Tap water, seafood, sugar, salt and honey.
Importantly, per year, the average person is consuming between 70,000 to over 200,000 particles of plastic. Why is that important? We know a lot about how in marine life, how they break down these plastics, and there’s about 14,000 different chemicals in a typical plastic mixture. Of that 14,000 chemicals, about 4000 are known to be toxins, toxins to the planet, toxins to marine life, toxic to humans. What happens is they break down and they break down into these components. Phthalates and BPA. You’ve all heard those things we worry about in terms of being estrogen mimics and causing hormonal problems. You’ve heard of polycyclic aromatic hydrocarbons and styrene. They can be associated with cancer. Importantly you see nickel and lead on this. Those are two heavy metals that can also be associated with inflammation and increase health disease.
Why do we worry about plastics? Well, unfortunately they exist from head to toe in our bodies. Now thanks to a lot of studies that have occurred throughout medicine, we’re seeing that microplastics are not only in our brain or our hearts, but they’re also in umbilical cord blood. They’re also in placenta. They’re in semen there and over there in follicular fluid. These are associated with diseases. Many papers have been published now over the past five years showing the association of microplastics and disease, like John had mentioned, the sea and that we worry about cardiovascular disease, neoplasia and neurodevelopment disorders are all unfortunately associated with microplastic burden now in our body. For example, a recent paper in Nature Medicine came out this past year showing that the number of microplastics in someone’s brain is associated with dementia. There’s also data out that came out of the New England Journal of Medicine showing that if people have high amounts of microplastics in their carotid arteries compared to those that do not, you have a two-fold increase in your rate of stroke and heart attacks. That’s similar to smoking about seven cigarettes a day for a lifetime. So microplastics are problem, and we need to think about how we can work to manage this.
This is a video that was done through I by my colleague in Australia, Peter Smith, and this shows you in the typical adult brain there’s about a teaspoons worth of plastic. Now it’s not this size, but this is for an image sake. Important to show that this plastic is added to the load of plastic that’s also in our bodies throughout our bodies, not just in our minds. With that in mind, how are we going to measure this? We’re using at Harvard, in my laboratory, a laser-directed infrared system to be able to measure microplastics. The reason this is important is because we could take two drops of blood. And this is, for example, a microscope in ten acts. And that shows you the plastics that were in a typical healthy person’s blood at about ten acts.
What we can do with this by our machine is look at the different types of plastics in that person’s blood. Why is this important? Because you can go back and look at the fingerprint, I’m going to call it of someone’s plastics, what they were exposed to. For example polyethylene is from soft plastic. It’s also from micro abrasion and scrubs that people use for their face. We were able to tell this person to use less of that. We’re also able to say that the number of rubber particles that was equivalent to silicone was associated with the cooking equipment that they were using in the kitchen, and were able to, over a period of three months, show that this plastic was able was reduced in their plasma by 80%.
The reason why I want to mention this is because we can measure, we can monitor, and then we can manage. And about every three months we can look at someone’s plasma and see how well they’re doing to reduce plastic use. Importantly, we can also talk to policymakers. There’s bills in California right now to reduce plastic use across our state, talk to businesses and look at safer alternative products.
One can use home filters, for example, to reduce your tap water exposure to plastics. There are ceramic filters as well as life straws that you can use to reduce plastics in the water supply. But importantly, there’s plastic alternatives now being used not just in regular household products, but also in the medical field, especially in hospitals. So I just want to talk about the fact that this is these are new businesses that are coming out, bio matter, organisms and tissues, as well as monomers and polymers that could potentially be used as alternatives and hopefully be much healthier.
In conclusion, human exposure to micro nano plastics is increasing. These are found in most organs of the human body. It’s associated with pathology, pathology and disease. These unfortunately are harbingers for microorganisms. This is also another place where antibiotic resistance will increase with the load of microplastics in the human body. Methods for detection and characterization need further standardization. We’re doing that under research now in my laboratory at Harvard, and the environmental policies are urgently needed to reduce plastic exposure. So in my lab called the Allergy Extreme Weather and Exposomics lab, we’re doing research not just on microplastics, but I have some of the kits that are in the living lab to show you we can take two drops of blood and not only look at microplastics, but also other toxins in the body.
This concept of exposomics is very important because it’s what you’re exposed to, both good and bad, at any one point in time and over someone’s lifetime. So now we can actually look at what you might have been exposed to when you were two years old, based on what lies in your DNA. So this is a very important concept. We’re doing more and more in terms of research on this, and there needs to be more research, not just in my own lab, but around the world, to be able to understand exposed omics and how it can improve the health span. Thank you.