Air pollution linked to negative changes in a baby's gut microbiome
A new study published in the journal Gut Microbes is the first to investigate the relationship between air pollution and a baby’s developing gut microbiome. The research found exposure to air pollution in the first six months of life is associated with a gut microbiome composition linked to allergies and inflammatory disease.
“The microbiome plays a role in nearly every physiological process in the body, and the environment that develops in those first few years of life sticks with you,” explained Maximilian Bailey, first author on the new study.
The new research follows on from a 2020 study by the same team that investigated the associations between microbiome composition and air pollution in around 100 young adults living in Southern California. Those findings were among some of the first to directly link air pollutants to changes in the gut microbiome.
Now, the researchers have turned their focus toward investigating the relationship between air pollution and gut bacteria during those crucial first few months of an infant’s life. In this study fecal samples were analyzed from around 100 infants aged six months.
As with prior investigations, individual exposure to air pollution was calculated by linking a subject’s street address to air quality monitoring systems from the U.S. Environmental Protection Agency. This allowed the researchers to estimate exposure to PM2.5, PM10 and NO2.
After adjusting for sex, birthweight, age, socioeconomic status and frequency of breastfeeding, the researchers found a number of significant associations between air pollution and gut microbial composition. Many of the bacteria identified in the study have been associated with inflammatory and metabolic diseases.
For example, the study found those infants with the highest level of exposure to PM2.5 pollutants had around 60 percent less Phascolarctobacterium in their microbiome compared to the infants with low PM2.5 exposure. Phascolarctobacterium is a genus of gut bacteria that has been associated with broad gastro intestinal health benefits.
On the other hand, those infants with the highest levels of exposure to PM10 pollutants had 85% more Dialister, a bacterium that has been linked to systemic inflammation, cancer, multiple sclerosis and mental health in adults.
“Overall, we saw that ambient air pollution exposure was associated with a more inflammatory gut-microbial profile, which may contribute to a whole host of future adverse health outcomes,” said Tanya Alderete, senior author on the study. “This study adds to the growing body of literature showing that air pollution exposure, even during infancy, may alter the gut microbiome, with important implications for growth and development.”
The researchers are cautious to stress there are plenty of caveats to go along with the new findings. The study only looked at single fecal samples from each subject, so it’s unclear what changes could develop in a child’s microbiome over time. Also, any health impacts from these findings are speculative and based on adult microbiome studies.
So there still is lot more work to be done before any links between air pollution, the microbiome and a child’s health can be confidently stated. But the researchers do suggest there is enough emerging evidence to indicate exposure to air pollution can influence the development of a child.
“Early life exposure to air pollution has been shown to negatively impact future health, including respiratory function, cognitive functioning and cardiometabolic health,” the researchers write in the study. “Collectively, increased rates of ventilation, rapid physiological growth, and the development of the gut microbiome make early life a critical window where exposure to AAP [ambient air pollution] may have disproportionately deleterious health effects.”
The new study was published in Gut Microbes.
Source: University of Colorado Boulder