We’ve known for a long time that plastics are ubiquitous. They are part of nearly all consumer products made in the past several decades, and they have been polluting oceans, land, air, and food systems since their widespread adoption. What has changed in recent years is not the presence of plastic, but our ability to detect it and to begin understanding the potential effects on our health and the environment.
Plastic pollution is persistent. Once plastic enters the environment, research shows it can take anywhere from about 100 to more than 1,000 years to break down, depending on environmental conditions. Even then, plastics do not disappear on any meaningful human or ecological timescale. They primarily fragment over hundreds of years into microplastics and nanoplastics, which circulate through ecosystems long before any complete breakdown occurs.
Research from the early 2020s indicates that more than 1,500 species across marine and terrestrial environments are known to ingest plastics, including fish, birds, mammals, insects, and soil organisms. In marine systems, microplastics have been detected throughout the food web, from plankton and other filter-feeders to larger predators. Because organisms at the base of the food web play a critical role in ecosystem stability, contamination at this level can disrupt entire ecosystems. Microplastics can also be passed along the food chain, allowing predators to accumulate higher concentrations over time, raising concerns for wildlife health, biodiversity, and increasing human animal exposure via the food chain.
One research team reviewed the literature about human animal consumption of microplastics that was available in 2019. They found that on average, we consume between 74,000 and 113,000 pieces of microplastics per year. That was a sample representing merely 15% of our caloric intake. They posit the real number might be several hundreds of thousands per year, since an estimate of the amount of microplastics from the air that settles on food during a meal means we are potentially ingesting an additional 13,731 to 68,415.
At the same time, scientists have been trying to understand what this means for humans. This has proven difficult, not because the issue is unimportant, but because the science itself is still being built. As Kathleen Egan, a cancer researcher at Moffitt Cancer Center, explained, findings have emerged slowly due to contamination risks, limited analytical tools, and a lack of standardized methods across fields. There is no agreed-upon manual for how to measure microplastics in the human body. Researchers are still developing the methods as they go, which makes early results harder to compare and interpret.
Despite these challenges, recent years have brought important breakthroughs. In 2022, for the first time in history, scientific research showed the presence of plastic particles in human blood, reporting a mean concentration of 1.6 micrograms per millilitre. Since then, another study refined and strengthened this research using improved analytical methods. This new study detected plastic polymers in 64 of 68 whole-blood samples, finding a mean concentration of 1.07 µg/mL, with levels ranging from 0.17 to 2.49 µg/mL. These results further reinforce the growing evidence that humans now carry measurable amounts of plastic within their bloodstream.
We are still in the early stages of understanding the health impacts of this. In 2024, one of the first studies to look directly at health outcomes, published in The New England Journal of Medicine, examined patients who had surgery to remove plaque from their arteries. The scientists tested the plaque for microplastics and nanoplastics and followed the patients for more than two years. Those whose plaque contained plastics, mostly polyethylene and PVC, the same materials used in packaging and pipes, were significantly more likely to have a heart attack, stroke, or die during that period than those without.
The United Nations Environment Programme also confirms the presence of plastics in human livers, kidneys, and placentas.9 Researchers examining human brains have also found that microplastic levels in brain samples collected in 2024 were about 50 percent higher than those measured in samples from 2016. Brain tissue also contained up to 30 times more microplastics than samples taken from the liver or kidneys.
This does not mean we fully understand the health effects of microplastics. However, we’re living at a time when scientific interest in the topic is exploding. In 2014, only about 20 academic papers indexed in major databases included the keyword “microplastics.” By 2024, that number had grown to nearly 6,000 papers.
As a society, we often approve materials and technologies long before we understand their long-term consequences. Regulation typically follows harm rather than preventing it, a process sometimes described as “graveyard regulation.” History offers many examples—airplanes, cars, opiates, lead, asbestos, and tobacco, to name a few—where warnings existed long before decisive action was taken. In many cases, regulators relied heavily on industry-funded research and acted only after widespread damage had already occurred.
It is unlikely that, if we look back a hundred years from now, science will conclude that chronic exposure to microplastics was beneficial; the best we can hope for is that it is harmless.
We will continue to follow the science on this topic as it evolves over the next years and decades, but we can’t wait to take action. The vegan philosophy requires that we act according to the precautionary principle. Considering all these factors, it seems that as far as our health is concerned, let alone the ethical consideration of killing and exploiting, it would be wise to stay away from eating animals altogether. By the same principle, it would also be wise to avoid the use of plastics, and not merely with token gestures like banning plastic straws.
