Intestines Sketch with Guts Bacteria

(© T. L. Furrer -

BOULDER, Colo. — Most studies into gut health focus on the diet, but could the air we breathe upset our stomachs too? That’s the conclusion of a news study out of the University of Colorado, Boulder. Researchers say poor air quality can have an adverse effect on the human microbiome and ultimately worsen gut health.

The study in the journal Environment International is the first-of-its-kind to connect gut health with air quality.

“We know from previous research that air pollutants can have a whole host of adverse health effects,” says senior author Tanya Alderete in university release.

Alderete adds that those previous studies tie the effects of smog to Type 2 diabetes, inflammatory bowel diseases, and weight gain. “The takeaway from this paper is that some of those effects might be due to changes in the gut,” she says.

Ozone’s affect on gut health

The report reviews fecal samples of 101 young adults in Southern California, determining the DNA sequencing in each person’s genes. Air-monitoring stations were kept near the participants during the study to check on their exposure to levels of ozone, particulate matter, and nitrous oxide.

Researchers find ozone has the greatest impact on gut health, with an 11-percent variation between the adults. They add gender, ethnicity, and diet all have less of an impact on your microbiome than ozone changes. Those with higher exposure to this gaseous pollutant have less variety in their gut bacteria.

“This is important since lower (bacteria) diversity has been linked with obesity and type 2 diabetes,” warns Alderete.

The Colorado team says the infamous “brown cloud” in Denver also consists of ozone and other harmful materials. California, Texas, Illinois, Connecticut, Indiana, New Jersey, New York, and Wisconsin have been penalized for their high levels of ozone concentration. According to study authors, air pollution kills 8.8 million people globally each year; more than wars and smoking combined.

The air you breathe can alter your body

Researchers reveal 128 bacterial species that increase ozone exposure. Some species impact insulin, the hormone that delivers sugar into muscles for energy.

“Ozone is likely changing the environment of your gut to favor some bacteria over others, and that can have health consequences,” Alderete explains.

The study results are limited due in part to the small testing pool and the fact that each volunteer only provided one sample each. Alderete is now conducting a larger experiment with a bigger budget. That research will include 240 infants. The assistant professor of integrative physiology is hoping these results influence lawmakers and city planners to move community areas like parks away from busy roads and other areas with high levels of air pollution.

“A lot of work still needs to be done,” concludes Alderete, “but this adds to a growing body of literature showing that human exposure to air pollution can have lasting, harmful effects on human health.”

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About Craig T Lee

Craig is a freelance writer who enjoys researching everything on the earth's surface and beyond. In his free time, Craig enjoys binge watching Netflix series and spending time with his friends.

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