Scientists say they may have discovered what causes so many unexplained cancers

A large-scale scientific study may have found a possible cause of many of the cancers for which genetics, diet and lifestyle cannot explain.

After reviewing more than 3,000 studies on microplastics, researchers concluded that these tiny toxins are linked to lung and colon cancer, as well as other lung diseases and infertility.

That could be significant because, unlike the dozens of cancer cases that are declining, the number of colon cancer cases is increasing, especially among young people who are not normally at risk.

Similarly, the number of lung cancer cases not caused by tobacco is also increasing, a trend that also baffles experts.

Microplastics are pieces of plastic with a diameter smaller than 5 mm that are released from consumer goods such as food packaging, clothing, toys, packaging, cigarette filters and tires.

They have contaminated the air we breathe, the food we eat and the water we drink and have been found in virtually every major human organ, where they cause widespread inflammation when the immune system recognizes it as a foreign invader.

This can cause a host of medical problems, including tissue damage and inflammation in the liver and heart, and over time, accumulation in the body can lead to irreversible damage.

The California researchers concluded that exposure to microplastics is ‘suspected’ to play a role in colon cancer, ovarian function, sperm quality and respiratory diseases, including lung cancer.

Previous studies have even discovered the substances in people’s brains and women’s placentas and estimate that exposure to microplastics costs the US healthcare system $289 billion annually.

And with plastic production expected to triple by 2060, the UC researchers said: ‘Due to the ubiquitous exposure and bioaccumulative properties of microplastics, the magnitude of human health impacts resulting from microplastic exposure is of great interest.”

The judgementpublished earlier this month in ACS Publications Environmental Science & Technology, analyzed approximately 3,000 animal and human studies examining a link between microplastic exposure and health outcomes in the respiratory, digestive and reproductive systems.

The studies suggested a strong link between microplastics and changes in the digestive system and colon cancer, as the small particles disrupt the protective mucus layer in the colon and may promote the development of tumors.

The researchers wrote: ‘We concluded that exposure to microplastics is ‘suspected’ to negatively impact the colon and small intestine in humans.’

They also wrote that microplastics are ‘suspected’ of causing cell death in the intestines and chronic inflammation, and of negatively impacting the intestinal immune system.

Overall, the researchers said: ‘Across the outcomes, we found that exposure to microplastics is ‘suspected’ to pose a digestive hazard to humans, including a suspected link to bowel cancer, using key features of the approach of carcinogenic substances.’

Microplastics are also suspected of affecting fertility as they can potentially affect hormonal balance in the reproductive system, damage semen quality and sperm count in men, and affect the function of the ovaries and placenta in women.

One of the studies found a link between microplastics in the placenta and low birth weight, while another found a link between microplastics in the amniotic fluid and preterm birth.

And exposure to microplastics is linked to adverse ovarian function and development.

Furthermore, the review said: ‘We concluded that exposure to microplastics is ‘suspected’ to negatively impact sperm quality and testicular health in humans.’

The UC team also discovered a link between microplastics and poor lung function, with the particles causing inflammation in the airways.

The particles cause lung damage and chronic pneumonia, which can increase the risk of lung cancer.

The researchers added: ‘From results fully evaluated, we determined that exposure to microplastics is ‘suspected’ to pose a hazard to the human respiratory tract.’

Commenting on the findings, senior author Tracey J. Woodruff, professor of obstetrics, gynecology and reproductive sciences at UCSF, said: “These microplastics are essentially particulate air pollution, and we know that this type of air pollution is harmful.”

The researchers wrote: ‘Microplastics are widespread and mobile in the environment and are detected in the air, surface water, coastal beaches, sediment and food.

‘They have been discovered in remote and pristine locations including Antarctica, deep ocean trenches and Arctic sea ice.

‘Due to their small size, microplastics enter the human body more easily and are dispersed there more easily than larger particles; Microplastics have been measured in human placenta, breast milk and liver.’

Companies around the world produce almost 460 million tons of plastic every year. This is expected to rise to 1.1 billion by 2050.

The paper is the first systematic review of microplastics using gold standard methods approved by the National Academy of Sciences.

Most of the studies in the review were based on animals, but the researchers said the conclusions likely apply to humans as well, because they share many of the same exposures.

The study builds on a report the researchers worked on last year with the California State Policy Evidence Consortium (CalSPEC).

The Consortium includes experts from across the UC system and provides evidence for policymakers in the California State Legislature.

“We urge regulators and policy leaders to consider the growing evidence of health harms from microplastics, including colon and lung cancer,” said Nicholas Chartres, PhD.

Chartres, the study’s first author, led the science and policy team at PRHE and now works at the University of Sydney.

“We hope state leaders will take immediate action to prevent further exposures.”