How do micro plastics find their way into the food chain & affect Human Health?

“Evolution doesn’t always mean progress. It means change. And life can change for better or worse. Today, the human body is changing in ways that have nothing to do with the survival of the fittest. Instead, we’re adopting and passing down traits that are detrimental to our health”, an excerpt from the Book "Breath: The New Science of Lost Art" by James Nastor. This concept, called dysevolution, was made popular by Harvard biologist Daniel Lieberman.


One of the points, this book focuses on the modern food habits that have changed the human skull in the past few decades. Due to this change, we are not able to breathe like our ancestors. This is the most important reason why humans suffer from modern ailments. While reading this book, I couldn’t fathom, how drastically human bodies would transform after a few years of ingesting plastic? And I started to ponder, if there is enough research to reveal the long-term effects of ingesting plastic.


Microplastics are small fragments of plastic material that have broken up into very small particles and are not visible to naked eye. Let us just understand the impact of these plastics, microplastics & microfibers on human health.


Read "Sources of Mircoplastic" here.

effects of microplastics on humans

Previously, micro plastics have been measured in tap water and bottled water, and in the air that we breathe. In a study conducted in 2018, 8 participants had shown to ingest micro plastics, which accumulate in the gut and may cause a slew of negative physiological effects (Lei et al., 2018). These participants came from across the globe: Finland, Italy, Japan, the Netherlands, Poland, Russia, the UK and Austria. The stools were tested for 11 kinds of micro plastics, of which up to nine were identified in each participant. An average of 20 micro plastic particles per 10 grams of stool were found, with polypropylene (PP) and polyethylene terephthalate (PET) -- major components of plastic bottles and caps -- found in all of the participants. Since, the sample size was too small, this study wasn’t widely accepted.


Infertility, inflammation and cancer in wildlife and animals have been linked to micro and nano plastic exposure to, but health outcomes in people are still unknown. The most shocking news that science has researched so far is the evidence of plastic contamination in tissue samples taken from the lungs, liver, spleen and kidneys of donated human cadavers. "We have detected these chemicals of plastics in every single organ that we have investigated," said senior researcher Rolf Halden, director of the Arizona State University (ASU) Biodesign Center for Environmental Health Engineering.


How did we get there?


In August 2020, a first peer-reviewed study by University of Catania scientist Margherita Ferrante published that Micro- and nano-plastics in edible fruit and vegetables. MPs are capable of penetrate the seed, root, culm, leaves and fruits plant cell based on their size and type (Dietz and Hertz, 2011) and this is the only study on plants; no study is available on the edible plants.


Another study published in Nature Sustainability from researchers at Yantai Institute of Coastal Zone Research, in China, and Leiden University, in the Netherlands, found that cracks in the roots of lettuce and wheat crops can take in microplastics from the surrounding soil and water. Those microplastics can then travel from the roots up to the edible parts of the crop. Though researchers already knew that very, very small particles—about 50 nanometers in size—could penetrate plant roots, Willie Peijnenburg, an environmental toxicology professor at Leiden University, says his study found that particles about 40 times that size can get into plants as well.


So far, microplastics have been discovered in apples, carrots, pears, broccoli and lettuce. Root vegetables including radishes, turnips and parsnips could also be contaminated. Microplastics have previously been identified in meats including chicken, canned fish, shellfish and other marine animals.

Scientists have argued for decades that this was 'impossible', claiming they were 'too large' to fit through the pores in the roots. Finally, we have the proof that plastics are in the fruit and vegetables we eat. 


Though microplastics are considered as pollutants, they may be more complex in their occurrence and their interactions with biosphere than other commonly recognized pollutant classes like persistent organic pollutants, pesticides and heavy metals. Microplastics are unique due to the diversity of ways in which soil organisms may themselves be able to affect their occurrence and distribution and mediate their effects on the rest of the soil food web. Microplastics may also have non‐toxicological effects, such as particles immobilizing soil microarthropods by filling pore spaces (Kim & An, 2019).

sources of microplastics in water and food

Now that science has started connecting the dots from extraction, to our usage, to its breaking up, to entering our food chain, and being found in the gut and human organs. Looks like it’s not as straightforward as it may look like.


People who want to avoid ingesting plastic are out of luck, given all of the plastic in the environment that's constantly being ground down into microscopic particles. It's impossible to completely protect ourselves from plastic ingestion. Can we expect our medical science to rapidly research the impacts and ways to keep micro plastic away from our body?


They say, “You become what you eat.” Will a doctor ever be able to recommend a plastic free diet?


P.S: Stay tuned for our next posts on & "Impact of Microplastics on the Environment."

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