New research from UCLA suggests air pollution, well known to have negative health effects on the lungs and heart, may also cause damage to other systems in the body.

The team of researchers, led by Dr. Tzung Hsiai, professor of medicine and bioengineering at the David Geffen School of Medicine at UCLA, found that exposure to air pollution caused mice to experience changes in the normal composition of gut bacteria. This produced a cascade of negative health effects. Changes in gut bacteria promoted the circulation of cholesterol in the bloodstream, and the increased presence of cholesterol in the bloodstream promoted the formation of plaque in the arteries, known as atherosclerosis.

“Our research provides new insight into the detrimental effects of environmental factors on our gut–vascular health,” said Dr. Zhaoping Li, director at UCLA’s Center for Human Nutrition. “If similar changes are exhibited in humans, exposure to air pollution could potentially lead to both inflammatory bowel disease and atherosclerosis.”

Prior epidemiological studies have associated air pollution with gastrointestinal disorders and with cardiovascular diseases. This new research in mice is the first to determine the mechanism by which this may happen and the link between the two. The findings, published in the journal Scientific Reports, suggest that the gastrointestinal and cardiovascular issues are not separate but rather are intertwined. Damage to the arteries may be due to changes in gut bacteria.