Microscopic pieces of plastic in the air we breathe and the food we eat could be fueling an epidemic of colon cancers in America, new research suggests.
Colon cancer diagnoses have surged in the US over the past two decades, with fit, otherwise healthy people in their 20s and 30s increasingly being struck down by the disease.
Obesity, ultra-processed foods, and taking antibiotics have all been blamed, but scientists are racing to find a definitive cause.
Now, a sweeping review of more than 3,000 studies suggests that tiny particles smaller than a grain of rice could be to blame.
The researchers, from the University of California San Francisco (UCSF), said these pervasive particles can accumulate in organs over time, causing irreversible DNA damage.
This leads to chronic inflammation that kills healthy cells and causes cancerous cells to grow out of control.
The researchers are now urging lawmakers to ‘take immediate action’ to limit exposure future exposure to microplastics.
Researchers in California suggested that microplastics, which are found in everything from single-use plastic to seafood, could be to blame for America’s colon cancer epidemic
The above graph shows the increase in US colorectal cancers in men and women from 2000 through 2021
Dr Tracey J Woodruff, a professor of professor of obstetrics, gynecology and reproductive sciences at UCSF, said: ‘These microplastics are basically particulate matter air pollution, and we know this type of air pollution is harmful.’
Colon cancer is one of the fastest growing forms of cancer, particularly in Americans under 50. These cases are considered early-onset.
Cases are expected to rise by 90 percent in people 20 to 34 years old from 2010 to 2030.
The review, published Wednesday in the journal Environmental Science & Technology, looked at 3,000 studies conducted between 2018 and 2024.
The team said while most research cited was conducted in animals, the conclusions would also likely apply to humans since humans and animals share the same exposures.
The researchers also pointed to several studies suggesting that microplastic exposure could increase the risks of structural changes to the colon.
One 2022 study of mice in China, for example, found that mice chronically exposed to microplastics had ‘remarkable colonic impairments’, such as damage to the colon’s walls.
Another study published the same year suggested that microplastic exposure caused the colon to produce less mucus, which forms a protective layer around the colon.
The Environmental Working Group, an activist organization centered on environmental pollutants, mapped out the communities and military sites confirmed to have PFAS contamination. Like microplastics, PFAS are found virtually everywhere in the environment
If the colon can’t produce mucus, the intestinal walls can’t protect against contaminants like microplastics and bacteria.
Mucus also lubricates the colon and helps stool pass easily. When stool builds up in the colon, it irritates the colon and inflames the inner lining.
This inflammation has been shown to kill off healthy cells and promote the formation of cancer cells, while also inhibiting the immune system’s ability to fight back.
The researchers wrote: ‘We concluded that exposure to microplastics is “suspected” to adversely impact the colon and small intestine in humans.’
They also suggested that inhaling microplastics could increase the risk of tissue damage in the lungs and trigger chronic inflammation.
Microplastics are ubiquitous in the environment, circulating through the air and leeching into the human body from contact with contaminated food, water, and soil.
They also can seep into the bloodstream via synthetic clothing and cleaning products.
They are most common in plastic bottles and containers, cosmetics, cleaning products, and foods that come from oceans like seafood.
Raquel (left) was just 28 when doctors diagnosed her with stage four colon cancer. Evan White (right), from Dallas, was diagnosed with colon cancer at age 24. He died four years later, just weeks before hs wedding
Experts recommend cutting down on single-use plastics, filtering water, and avoiding clothing with synthetic fibers to cut down on exposure.
Earlier this year, researchers in Brazil found microplastics in human brains for the first time, suggesting they entered through the nose.
And research published in 2022 found microplastics in the blood of eight in 10 study participants.
There were several limitations to the new research, with the main one being the authors’ reliance on animal-based studies.
The team said that ‘it is likely our conclusions underestimate the true health impacts of microplastic exposure.
‘Importantly, these limitations highlight that there are clear opportunities for future research.’
The researchers are urging lawmakers in California and other states to place restrictions on microplastic usage.
Dr Nicholas Chartres, lead study author and senior research fellow at the University of Sydney, said: ‘We urge regulatory agencies and policy leaders to consider the growing evidence of health harms from microplastics, including colon and lung cancer.
‘We hope state leaders will take immediate action to prevent further exposures.’
