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Scientists Find Link Between Microplastics and IBD Symptoms

People with IBD had greater levels of microplastics in their feces than healthy controls, but it's not clear yet whether these pollutants are a true trigger.

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A scientist collecting microplastic waste for research on the beach of Contis, southwestern France, on August 17, 2020.
A scientist collecting microplastic waste for research on the beach of Contis, southwestern France, on August 17, 2020.
Photo: Mehdi Fedouach/AFP (Getty Images)

Scientists this week have reported an interesting correlation between microplastics and inflammatory bowel disease (IBD). Those with diagnosed IBD, the researchers found, had noticeably greater levels of microplastics in their feces than healthy controls. The findings could suggest that these pollutants have a causative role in IBD, the researchers say, or indicate that people with IBD are more likely to collect microplastics in their gut.

Inflammatory bowel disease, not to be confused with irritable bowel syndrome (IBS), is a debilitating, chronic, and complex digestive condition. It comes in two major forms, ulcerative colitis and Crohn’s disease, both of which are characterized by damaging inflammation along the digestive tract. Symptoms include abdominal pain, fatigue, diarrhea, rectal bleeding and weight loss, though these symptoms typically appear as flare-ups with periods of remission in-between.

IBD is caused by a wayward immune system that attacks the gut, but the exact reasons why this immune dysfunction happens in the first place are still largely unknown. Genetics does play a part since a family history of IBD is associated with a higher risk of developing it yourself. Environmental factors may also act as a trigger for IBD episodes. This could include infections from certain viruses and bacteria, or exposure to select foods or other substances that we inadvertently ingest.


It’s that last category that made researchers at Nanjing University in China curious about microplastics, the tiny fragments of slowly degrading plastic that end up in the environment. People are constantly exposed to microplastics and the hormone-disrupting chemicals they carry, and this exposure is widely considered to harm human and animal health, though research is still ongoing into what these harms truly are. One theory is that they can cause or increase the risk of inflammation in various parts of the body, including our gut.

The researchers looked at fecal samples taken from 52 people with diagnosed IBD throughout China, and compared them to 50 healthy people aligned in similar demographic factors like age. Those with IBD, the team found, had significantly higher levels of microplastics in their poop on average than the control group. Among those with IBD, researchers also found a link between greater amounts of microplastics and a greater severity of reported symptoms. The findings, published this week in Environmental Science & Technology, are the first to compare levels of microplastic exposure between IBD patients and healthy controls, the researchers say.


It’s certainly possible that there could be a true cause-and-effect link between plastics and IBD symptoms. But it’s important to note that this kind of study can only find a correlation between the two, not show causation. People exposed to more plastics may be different from those exposed to less plastics in other important ways that could better explain their perceived higher risk of IBD, for instance. The link between plastics and IBD could also go the other way, the authors point out. The damaged guts of IBD patients could somehow allow more microplastics to accumulate in the body as they pass through the digestive tract from the food and water they ingest, they argue.

Right now, this research should only be intended to elicit more study into the connection, if any, between microplastics and digestive problems like IBD, the authors say. And unfortunately, without systemic changes in our manufacturing process, there’s very little a single person can do to reduce their exposure to microplastics (just this week, scientists managed to find them in the remote heights of the European Alps). Interestingly enough, though, the current study did find that people who reported drinking more bottled water, eating more takeaway food, and being exposed to dust more often did have higher levels of microplastics, across both groups.