Microplastics: What to tell your patients about this increasing threat

By Naveed Saleh, MD, MS | Fact-checked by Barbara Bekiesz
Published September 19, 2023

Key Takeaways

  • Microplastics are found in nearly everything and permeate our water, food, and air.

  • Experimental evidence about the negative impact of microplastics on animal models and human cells is established, although there is a paucity of direct clinical evidence.

  • Physicians should advise their patients on the best way to avoid exposure to microplastics at home, though many experts admit there are few effective interventions currently available.

Microplastics have infiltrated every part of daily life. They’re found in the soil, in the water, and in the air. They’re found in our fruits and vegetables, meats and poultry, personal care items, and clothing. 

An expert opinion

MDLinx spoke with Heather Patisaul, PhD, from the Center for Human Health and the Environment at NC State University, about the ubiquity of microplastics in our environment.

“It is now clear that we all have micro- and nano-plastics in our bodies,” Dr. Patisaul says. “Animal and some human studies show that they can get anywhere and everywhere, including to the brain, lungs, kidneys, liver, breast milk, and placenta.” 

"And it's not just the plastic itself that is potentially hazardous to health, but also all the industrial chemicals they stick to and carry along with them."

Heather Patisaul, PhD

What’s the evidence?

In preclinical studies, the health effects of microplastics have been demonstrated, as reported in the Yonsei Medical Journal.[] For instance, microplastic-fed mice demonstrated an increase in inflammatory-response proteins (eg, inducible nitric oxide synthase, cyclooxygenase-2) in the liver, kidneys, and intestines, as well as ROS production and superoxide dismutase activity.

Other studies have shown that mice exposed to nanoparticles by mouth harbored these nanoparticles in the central nervous system, which led to microglia activation and neuron damage.

“The detrimental health effects of microplastics have been observed in many experimental studies, suggesting that the risks for various inflammatory-related diseases in the human body is increasing,” the authors wrote. 

“However, few epidemiological or etiological studies have been performed to examine the occurrence of symptoms or diseases caused by microplastic exposure.” 

In addition to their detrimental effects in mice and rats, microplastics are toxic to human-derived cells, writes Zachary G. Jacobs, MD, in a post to the SGIM Forum for the Society of General Internal Medicine.[]

Microplastic toxicity affects the intestinal tract, central nervous system, heart,  reproductive system, and immune system. Other consequences include impaired pulmonary function, disturbance of the metabolic system, and an increased risk of certain cancers.

Potential effects on humans

As Dr. Jacobs explained, the mass production of plastic started after World War II and has been on the rise since. Globally, more than 400 million metric tons are generated each year, with estimates pegged at 1.1 billion metric tons per year by 2050.

Microplastics are defined as plastic particles between 1 and 5,000 micrometers in size. Nanoplastics are less than 1 micrometer in size and are derived from the degradation of larger plastic products during daily use, or other forms of degradation in the environment. Micro- and nanoparticles are particularly worrying, because they are small enough to be absorbed by cells.

Microplastics were first detected in human tissue in 2019. They have since been detected in human body fluids, blood, the colon, lymphatics, the spleen, and the lungs. They are also found in the meconium, breastmilk, and placenta, which points to fetal and newborn exposure. 

“The long-term risks of these now unavoidable exposures remain largely unclear, but we know from wildlife who consume and breathe them in that the outcomes can be pretty dire,” Dr. Patisaul tells MDLinx. “They wreck the lungs and gut, particularly the gut microbiome, and there is growing evidence they can also damage the liver, brain, placenta, and developing fetus.”

"Babies have some of the highest levels of micro- and nanoplastics in their feces, suggesting that exposure is worst for young children."

Heather Patisaul, PhD

“[This] situation will rapidly compound over generations if we do not get our plastic pollution under control. They pass from mother to child and up the food chain,” Dr. Patisaul says.

 Dr. Jacobs warned that minority populations will be most affected by microplastics. “Importantly, communities of color, indigenous populations, and low-income families will bear the greatest weight of these health impacts as they are disproportionately affected by plastic waste and production and are at the greatest risk of microplastic accumulation,” he wrote.

Counseling patients

Because microplastics surround us, it’s likely only semi-effective to try to limit exposure, according to Dr. Patisaul.

“To reduce levels in your home, you can buy clothing, sheets, curtains, and other textiles made from natural materials like cotton and bamboo instead of nylon or other synthetic materials.” Dr. Patisaul also notes that regular vacuuming (with a HEPA filter) and proper ventilation to reduce indoor accumulation are good steps.

“Get a reverse osmosis water filter on your most-used drinking water source and use the most protective air filters possible on your HVAC system. Switch out food containers to glass, and consider getting laundry balls and other devices that absorb microplastics in the laundry,” she says.

The SGIM Forum article suggests these useful tips that can be shared with patients:

  • Use plastic alternatives such as glass when microwaving

  • Drink filtered tap water and not water from plastic bottles

  • Avoid plastic-lined cups when drinking hot beverages

  • Choose cosmetics that are devoid of plastics

  • Avoid plastic-containing tea bags; drink loose-leaf teas instead

  • Always opt for food products packaged in nonplastic containers

What this means for you

The microplastics problem will only grow with the accelerating rates of plastic pollution. It is impossible to recycle our way out of this problem, thus it’s imperative that plastic production is cut on a global scale. At present, the human health implications of long-term microplastic exposure are not well understood, and direct clinical evidence is lacking. However, it’s still a good idea to advise patients to reduce their plastic exposure through a variety of means.

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