New BYU study links diesel exhaust exposure to obesity and metabolic diseases

PROVO, Utah ( ABC4 ) — A new BYU study has revealed a factor in obesity and metabolic diseases that you may not expect — diesel exhaust.

The BYU study found that exposure to exhaust from diesel engines is tied to “increased fat mass, enlarged fat cells, insulin resistance, and inflammation,” detailing that these changes can lead to conditions such as obesity, diabetes, and heart disease.

Data from the World Health Organization shows that 99% of the global population breathes air that goes beyond WHO guideline limits , with low and middle-income countries suffering from the highest exposures. BYU researchers sought out the implications air pollution could have on health.

“Two items have become increasingly clear to us: there are non-caloric influences on body fat, and inhaled pollution is one of them,” said the study’s senior author Professor Benjamin Bikman in the news release. “But what are the casual variables to this link? We wanted to know what was happening to the body at the level of the fat cell.”

Bikman, along with professors Juan Arroyo and Paul Reynolds and several students, studied how diesel exhaust can impact metabolic function through two groups of lab mice in a six-week study.

According to the study, one group of mice was allowed to “breathe room air,” while the other group breathed in diesel-exhausted particles 30 minutes a day for five days a week. Adipose tissue, known as body fat, was then collected from the mice.

Reynolds explained the exposure of diesel exhaust particles in the mice is within the range of what people in highly polluted areas may experience.

The researchers found the adipose tissue experienced significant changes after being exposed to diesel exhaust — such as the diesel exhaust particles increasing the size of fat cells. The study said this can be linked to insulin resistance and inflammation, which can contribute to metabolic issues.

The study also found that the mice who were exposed to pollution experienced an increase in visceral fat, the fat surrounding organs, and subcutaneous fat, fat just under the skin.

Researchers said the mice in the pollutant-exposed group developed systemic inflammation, which can be a factor in heart disease, type 2 diabetes, and autoimmune disorders.

“For so long we’ve considered being overweight and obesity strictly a function of overeating; the fat cell is more complicated than a caloric ATM. As much as we’re mindful of what goes in our stomachs when it comes to weight management, we should be increasingly mindful of what comes into our lungs,” Bikman said.

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