People with inflammatory bowel disease have 50% more microplastics in their faeces, a study has revealed. Previous research has shown that microplastics can cause intestinal inflammation and other gut problems in laboratory animals, but the research is the first to investigate potential effects on humans. The scientists found 42 microplastic pieces per gram in dried samples from people with IBD and 28 pieces in those from healthy people. The concentration of microplastics was also higher for those with more severe IBD, suggesting a connection between the two. However, the study does not prove a causal link, and the scientists said further research must be done. It may be that IBD causes people to retain more microplastics in their guts, for example. Microplastic pollution has contaminated the entire planet, from the summit of Mount Everest to the deepest oceans. People were already known to consume the tiny particles via food and water as well as breathing them in. Microplastics are known to harm wildlife but very little is known about their impact on people’s health, although a study published earlier in December found they damaged human cells in the laboratory. The study, published in the journal Environmental Science & Technology, analysed samples from 50 healthy people and 52 people with IBD, but otherwise healthy. The participants were from across China and also completed a questionnaire including information on their dietary and drinking habits in the previous year. As well as the link to IBD, the scientists found that people who tended to drink bottled water or eat takeaway food had about double the concentration of microplastics in their stools. In total, 15 different types of plastic were found among the microplastics. The most common were PET, used on water bottles and food containers and polyamide, which is also found in food packaging. The level of microplastics in the faeces was similar to those in the few previous studies conducted, once differences in methodology are taken into account. One study found infants had more microplastics than adults in their faeces. This may be due to infants chewing plastic items or use of milk bottles which are known to shed millions of microplastics. Diet and environmental factors can trigger or exacerbate IBD, which includes Crohn’s disease and ulcerative colitis. “In recent years, the prevalence of IBD has sharply increased in developing countries in Asia,” said the researchers from Nanjing University in China. “It is estimated that there will be 1.5 million IBD patients in China by 2025 which will cause a serious disease burden.” “This study provides evidence that we are indeed ingesting microplastics,” said Evangelos Danopoulos at Hull York Medical school in the UK, who was not part of the study team. “It is an important study, as it widens the evidence base for human exposures. More data about possible confounding factors is needed to build a causal association to specific human health conditions.”