Do microplastics shorten lifespan?

Are they even worth worrying about?

Microplastics are ubiquitous in the environment, and a growing abundance of research is raising alarm bells.

My question today: Is it worth worrying about microplastics when looking at healthspan and aging? (Or is this just something men need to worry about due to the new study on microplastics in testicles?)

First, what are microplastics, and how many people do they affect?

Defining microplastics:
While there is some discrepancy around the term, most current research studies seem to define microplastics as being from 1 mm to >0.1 μm, and nanoplastics as less than 0.1 μm. The term encompasses a bunch of different plastic compounds, with the most common being polystyrene and PVC.[ref]

In the blood:
A 2023 study in Spain found nanoplastics in all blood samples tested, even newborns.[ref]

Thinking about PVC swishing through my bloodstream isn’t comfortable, but how much of a problem is it for my long-term health and wellness?

Let’s look at the research:

Specific to lifespan, I found a couple of animal studies looking at the effect of microplastics.

• A 2023 study using fish as a model vertebrate species looked at the effects of microplastics compared to controls. The results showed that the “administration of MPs not only shortens the lifespan but also accelerates the development of age-related biomarkers”. Microplastics increase oxidative stress, reduce antioxidants, reduce digestive enzymes, and cause liver dysfunction.[ref]

• Studies in C. elegans also show that microplastics decrease lifespan.[ref][ref] However, in male fruit flies, microplastics seem to increase lifespan.[ref]

What about in humans?

There aren’t any lifespan studies in humans... so let’s look at what kills people - heart disease, neurodegenerative diseases, diabetes, and cancer - and see if microplastics influence these diseases.

Heart disease is the number one cause of death. Microplastics have been found in atherosclerotic plaque samples from people undergoing heart surgery. In one study, 80% of the plaque samples had microplastics in them.[ref] Another recent study found that 58% of the carotid artery plaques had polyethylene in them, and 12% had PVC in the plaque.[ref] I think more research is needed here to know for sure that the interaction of microplastics with the lining of the blood vessels is specifically causing atherosclerosis, but the studies so far are pretty damning.

Neurodegenerative diseases: Research shows that microplastics can influence the misfolding of proteins, such as amyloid-beta.[ref] More specifically, polystyrene nanoparticles significantly accelerate the rate of amyloid-beta plaque formation at low levels.[ref] Cell studies and animal studies also show that nanoplastics may play a role in the pathogenesis of Parkinson’s disease.[ref] I couldn’t find any direct evidence, though, of nanoplastics causing Alzheimer’s or Parkinson’s in humans.

Diabetes is a leading cause of health-related problems later in life. Animal studies show that the role of nanoplastics in type 2 diabetes isn’t clear-cut and likely depends on the type of plastic.[ref] Microplastics may compound the problems with a poor diet. In mice, adding microplastics to a high-fat diet increases metabolic problems (high blood glucose, NAFLD). The microplastics altered the gut microbiome and exacerbated problems with leaky gut. In mice fed a normal diet, microplastics didn’t have as much of an effect on metabolic issues.[ref]

What about cancer? Oddly, I didn’t find much research on microplastics or nanoplastics and cancer. A new study, though, did find microplastic polymers in all of the liver samples from people with cirrhosis but none in healthy liver tissue.[ref]

My takeaway:

The research clearly shows that nanoplastics can and do circulate in the bloodstream and penetrate tissues and cells. This increases oxidative stress in cells, leading to cell death in some situations. Here’s a good overview if you want to read more.

Let’s dig into where the plastic particles come from and what we can realistically do about reducing plastic in the body.

Sources of microplastics:

According to one review study, the biggest source of microplastics for humans is through food. Specifically — bottled water, seafood, sea salt, honey, beer, and “food components”. Behind food, air pollution is another source of microplastic exposure. Tires contain plastics, and every time we drive, we add a bit to the air.[ref]

A study of tea bags showed that a single plastic tea bag (nylon and polyethylene terephthalate) “releases approximately 11.6 billion microplastics and 3.1 billion nanoplastics into a single cup of the beverage.” The study contends that the plastic particles released from the tea bag are orders of magnitude higher than plastics in other foods.[ref]

Plastic cups are another big source of microplastics. Hot beverages in disposable cups have more plastic in them than cold beverages. Even paper coffee cups that are lined give off plastic.

Below is a screenshot from the results of the study looking at different temperatures.

EPS is expanded polystyrene, PS is polystyrene, PP is polypropylene (PP), and PE is polyethylene coated paper coffee cups. I was surprised that EPS (styrofoam cups) weren’t the worst. Interestingly, rinsing the cup before using it cut the microplastics in half.

Note to self: Always rinse out a plastic to-go cup before getting a drink.

What can I do about microplastics?

Here’s what I see as the low-hanging fruit — the easier-to-implement steps that make the biggest impact.

Tea bags made with polypropylene or nylon fibers dump a lot of microplastics into your tea. Hot water and thin fibers lead to lots of tiny fragments. Going with a brand that doesn’t use plastic in their tea bags or going with loose-leaf tea seems to be a doable switch. (My question, without an answer - what about my coffee maker with plastic parts inside?)

Seafood is a real conundrum. While it is good for you in a lot of ways, the research on most seafood containing microplastics is pretty compelling. I may stick with fresh-caught trout from Montana rivers (because I live by a river in Montana known for trout fishing) and cut down on the frozen shrimp.

Stop drinking anything bottled in plastic. While tap water can have some microplastics in it, apparently, plastic bottled water is much worse. Beer seems to have a microplastic problem also.

Rinse the cup first: If you’re going to drink a to-go cup of coffee from the hotel or gas station, rinse out the cup first to cut the microplastics significantly. If you’re getting a soda or water at a fast-food restaurant, do a quick rinse of water first.

Prioritize melatonin production (avoid blue light for two hours before bed.) A mouse study showed that melatonin reduced the amount of nanoplastics absorbed in the intestines and reduced the amount that reached the rest of the body.[ref]

I’m going to end with a more abstract idea: Avoid leaky gut. While this is really vague, a lot of the studies on microplastics point to them being a problem when the gut barrier is compromised, such as by alcohol or leaky gut.[ref] Things that reduce the intestinal mucosa, like alcohol or emulsifiers, can result in leaky gut due to gut microbes activating your immune response.

Conclusion:

For me, the current research on nanoplastics is raising alarm bells and is enough to get me to change some of my habits. Specifically, the study on atherosclerotic plaques containing nanoplastics was a real eye-opener.

The obvious step of storing food in glass instead of plastic was a switch that I made years ago, and I think everyone knows not to microwave in plastic.

Taking a ceramic or stainless steel cup with me when traveling in order to avoid drinking coffee from a to-go cup is a habit that I need to get into. And rinsing any plastic or paper cup before filling it seems like a no-brainer. Switching from tea bags to a loose tea is also easy, and I do have a handy little tea strainer that I like. I already prioritize sleep and take a low-dose, timed-release melatonin supplement, and I have an RO filtration system for my water. Potential microplastic sources that I haven’t found a solution for yet include milk (can’t find it in glass bottles here) and packaged foods.

What are you doing to minimize microplastic consumption? Did I miss anything big here? Let me know in the comments.