Pollution may disrupt the gut microbiota, according to a team of researchers at the University of Colorado Boulder.
Air pollution has a negative impact on our health. It has been identified as the 5th leading risk factor for mortality worldwide. Indeed, it can be responsible for chronic diseases, especially respiratory diseases. However, our lungs are not the only ones poisoned by the air we breathe. The intestinal microbiota would also be.
Pollution and microbiota: the first clinical trial
Animal model work suggests that exposure to air pollutants may alter the microbiota composition. Armed with this observation, American researchers enrolled a hundred overweight young Californian adults in a study to verify this result on humans.
The main investigations carried out were:
- The air quality of the volunteers’ place of residence, studied via monitoring stations located nearby. The data collected provided information on subjects’ exposure to ozone, particulate matter and nitrogen oxides.
- The composition of the intestinal microbiota, analysed by genomic sequencing from the collected fecal samples.
Ozone, the main incriminated pollutant in the disturbance of the intestinal microbiota
According to the researchers, ozone was the main pollutant responsible of the intestinal microbiota dysbiosis. This imbalance was manifested by a loss of diversity and a reduced number of bacterial species. In fact, almost 128 bacterial species have been impacted. Some of them would act on insulin secretion, while others would produce metabolites such as fatty acids, involved in maintaining the intestinal barrier integrity.
Breathing these pollutants could therefore have a significant impact on health. Several studies have shown that reduced gut bacterial diversity is associated with various disorders or diseases. For example, the risk of obesity, type 2 diabetes, gastrointestinal disorders and other chronic diseases could increase.
It should be noted that the study shows some limitations. Indeed, only one stool sample per person was collected. Nevertheless, it provides major data on the pollution effect on the gut microbiota, and thus on our health. Further studies are needed to complement these results. A study exploring the impact of prenatal or early exposure to air pollution on the development of gut microbiota in 240 infants is currently underway.
Pollution is a major health issue. Reducing it is essential if we want to protect our health, but also our earth.
LC
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