Nature

Breathing Polluted Air Leads to Weight Gain After Just 3 Weeks, Study Finds

February 24, 2016 | Kelly Tatera

Lab rat
Photo credit: Joanna Servaes/wikipedia (CC by SA 3.0)

Pollution may be contributing to obesity more than we realize.

In an unsettling new study published in the Journal of the Federation of American Societies for Experimental Biology, researchers found that laboratory rats exposed to the highly polluted air in Beijing gained weight after just three weeks of exposure.

In order to explore the effect of pollution on weight gain, cardiorespiratory, and metabolic functions, the scientists split pregnant rats and their offspring into two groups: one lived in a chamber where they were exposed to outdoor Beijing air, and the other lived in a chamber with an air filter that removed most of the pollution particles.

After just 19 days, the mother rats who were exposed to the polluted air had 50 percent higher LDL cholesterol, 97 percent higher total cholesterol, and 46 percent higher triglycerides — the main constituent of body fat in humans and animals. They were heavier and showed increased tissue inflammation, and their insulin resistance level was higher than the rats who lived in the chamber with clean air.

SEE ALSO: Is Pollution Making Us Fat?

Similar results were seen in the rat offspring who lived with their mothers. However, although the negative effects of air pollution were observed after just three weeks, they weren’t as striking as the results seen after eight weeks, suggesting that the continuous inflammatory and metabolic changes that lead to gaining weight may only occur after long-term exposure to pollution.

Compared to the rats that breathed in clean air, the male and female rats exposed to pollution were respectively 10 percent and 18 percent heavier. The pollution-exposed rats were significantly heavier even though the scientists fed all of the rats the same diet.

All of this data supports the study’s conclusion that exposure to air pollution results in metabolic dysfunction, which is a precursor to obesity. Previous studies have found that air pollution can have negative effects on weight, inflammation, and metabolism, and these findings further confirm the health risks linked to air pollution exposure.

“Since chronic inflammation is recognized as a factor contributing to obesity and since metabolic diseases such as diabetes and obesity are closely related, our findings provide clear evidence that chronic exposure to air pollution increases the risk for developing obesity,” senior author Junfeng “Jim” Zhang, a professor of global and environmental health at Duke University, said in a press statement.

“If translated and verified in humans, these findings will support the urgent need to reduce air pollution, given the growing burden of obesity in today’s highly polluted world.”

One study found that exposure to air pollution can affect short-term memory and IQ, and other research has even linked air pollution with an increased risk for autism and schizophrenia. Not only is it so critical to clean up the air in order to preserve the environment, but mental and physiological health is also at stake.

Considering the fact that a Canadian start up company became successful by selling bottles of clean air to China, it’s safe to say that more efforts must be focused on cleaning up the air we breathe.

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