Micro and Nanoplastics

The first rule of this newsletter: Don't Panic

If you didn’t know this already, a paper came out in the New England Journal of Medicine that showed micro and nanoplastics in arterial plaques. This has caused some amount of panic and even the All-In VC Bros/Besties has weighed in on it (I know a bunch of you readers probably listen to that podcast). Therefore, in breaking with my own internal rules on writing about this stuff I felt the need to weigh in and discuss. These are my own opinions and do not reflect any opinions of my current employer or past employers. This is not medical advice. This is opinion writing and entertainment.

The Paper

Marfella et. al. published a paper in the New England Journal of Medicine (NEJM) on March 7, 2024, where the goal was to better understand the role of micro and nanoplastics on cardiovascular disease. This resulted in the authors analyzing plaques (the stuff that causes heart attacks) and their composition. The topline results of the study showed that 58% of the prospective study participants had 21.7 ±24.5 μg of polyethylene per milligram plaque.

This means that about 2% of the plaque was polyethylene by weight in 58% of the study population.

Further, 12% of the participants had 5.2 ±2.4 μg of polyvinyl chloride per milligram of plaque.

This means that about 0.5% of the plaque was polyvinyl chloride by weight in 12% of the study population.

The researchers’ analysis of the data show that people with micro and nanoplastics contained within their plaques were at a higher risk of having worse outcomes compared to people without plastic in their plaques. This data is based on the study’s endpoints which is essentially heart attacks and strokes (myocardial infarction = heart attack; MNPs = micro and nanoplastic particles):

The primary end point was a composite of nonfatal myocardial infarction, nonfatal stroke, or death from any cause among patients with plaque containing MNPs and patients with plaque that did not contain those substances. Secondary end points included levels of tissue biomarkers interleukin-18, interleukin-1β, tumor necrosis factor α (TNF-α), interleukin-6, CD68, CD3, and collagen in patients with evidence of MNPs as compared with those without.

Figure 4. From the NEJM paper showing patients with micro and nanoplastics (MNP) in plaques had more adverse events (see endpoints) than those who did not.

The study’s own authors caution that this data does not link micro and nanoplastics to causing heart attacks or strokes:

It is important to note that our results do not prove causality. The association between the presence of MNPs within plaque and the incidence of a composite of cardiovascular disease or death outcomes may also entail the risk from exposure to other residual, unmeasured confounding variables, such as unknown exposures during the life course of the patient or, more broadly, the health status and behaviors of the patients. In addition, we did not consider levels of exposure to PM_2.5 and PM₁₀, which is an emerging risk factor for cardiovascular disease.

My Thoughts on This

There definitely need to be more studies on this topic. The key to the future studies will be trying to prove causation of either increased risk of strokes or heart attacks due to micro and nanoplastics. Without having clear irrefutable evidence this issue will become a cultural and political talking point where people take sides, gridlock ensues, and nothing meaningful happens except that there are going to be even more gigantic Stanley cups out there, but with stainless steel straws.

To me, in this one study, it appears that micro and nanoplastics are present in plaques and this alone is concerning. A plaque containing 1-2% by weight of plastics doesn’t sound like a lot, but the fact they are there is concerning to me. Also, once those particles are in the body, do they ever come out?

I’m not here to fear monger. I am more concerned now than I was before on this issue. I also think the methods in identifying these plastics needs to be robust (see methods section below). The fact that micro and nanoplastics break off from larger pieces of plastic is not surprising to me nor is their proliferation into the environment. We’ve known for a long time that particle pollution is bad for human health and it’s why you don’t want to live next to a busy highway.

Additionally, the benefits of plastics and synthetic polymers in modern life is clear. I don’t think we could function without them from basic infrastructure to packaging to durable goods like the very keyboard I’m using to write this newsletter.

When I was younger (middle school and high school) I really enjoyed reading Science Fiction and Fantasy genre novels. I always thought that the best magic systems out there were ones that enacted a price to use. If a character wanted to magically heal someone of a life-threatening wound—it was going to cost them in some other way. We can think of modern life as living with magic, but for every bit of magic we have in our current lives we pay a price somewhere else.

Sometimes those prices are evident and clear to us. There is a price to binging all the seasons of Game of Thrones and not going outside and exercising (thank you Fios internet and the plastic cladding around the fiber optic cable).

Sometimes we aren’t even aware of the price of the magic we get to use on a daily basis until people start investigating. In the 1990s, a Teflon coated pan allowing us to cook eggs without butter or oil was magical. The price we paid for Teflon and the magic it gave us was PFAS contamination in the environment (see this post about DuPont).

Modern synthetic polymers and plastics are about as close to real magic as we will experience. Modern synthetic polymers and plastics enable things that would be considered magical even 100 years ago.

During graduate school I tried to design alternatives to bisphenol A using biomass derived feedstock chemicals. In short, this was almost impossible because bisphenol A is essentially magical in how restriction of rotation of the phenol rings and its three-dimensional structure imparts amazing properties for epoxy resins and polycarbonates. Designing around BPA is really difficult and getting something that can just drop-in and replacement still hasn’t been done. The big price we need to pay for bisphenol A based resins is running the cumene process to make phenol and acetone, which is based on a ready supply of benzene and propene (see this thing I wrote about crude oil) and the potential harm of bisphenol A on the endocrine system.

My advice here is to go read Mark Twain’s “A Connecticut Yankee in King Arthur’s Court.” Spoiler alert, even a semi-modern Connecticut Yankee engineer is considered a magician to Arthurian England due to possession of some basic science and engineering skills. Despite all his “magic,” he still cannot influence history that much because, well humans are going to be human.

If you don’t want to read Mark Twain, then I guess the best thing to do is just try to make informed decisions on how you want to live your life. If you want to be as plastic free as possible, I think you should do it. If you love drinking water out of a plastic bottle you should do it. I’m still going to be storing shredded cheese in high density polyethylene deli containers that I’ve been reusing from takeout dinners. I’ll still be using disposable coffee cups lined with polyethylene. I’ll still use reusable water bottles both made from plastic and stainless steel.

I know that consumption of processed and cured meats and saturated fat increases my risk of heart disease and yet I still love a bacon, egg, and cheese on a roll from a NYC bodega. If you haven’t had one of these magical sandwiches, then you haven’t really lived.

Tony

The Methods (if you’re interested)

The researchers in the NEJM paper used a method called pyrolysis gas chromatography - mass chromatography (Py-GC/MS) to analyze if plaques contained plastics. This method involves heating up the material without oxygen to combustion temperatures and/or beyond and it turns solids into gases. Pyrolysis is essentially how we make charcoal from wood. Researchers at NIST are trying to use this method to better understand plastic identification, additive identification, and how the method can be standardized and become more useful (e.g., build an open library anyone can access and use to identify plastics and additives via the method).