Air Pollution Causes Obesity? Breathing In Smog Can Cause Cardio-Respiratory And Metabolic Dysfunctions Raising Risk Of Abnormal Weight Gain

Air pollution may be causing obesity. A new study has indicated that breathing in smog causes abnormal weight gain.

A new study by Duke's University, USA indicates breathing in polluted air for just a few weeks can substantially increase the risk of obesity. Smog, which is common in cities, isn't just responsible for causing cardio-respiratory and metabolic dysfunctions, but may be forcing your body to bulge, reported News Max. In essence, inhaling polluted air for a few weeks isn't just harming your lungs, but may also be forcing you to gain weight in an unhealthy manner.

The researchers have conducted the study on pregnant mice, but the findings could have a long term impact on the ways obesity is tackled and managed in developed cities, as they are the mostly likely regions to experience severely deteriorated air quality. Incidentally, the rats gained weight merely by being exposed to polluted air, despite all other conditions being normal.

It essentially means toxic air is significantly altering body's metabolism. The fundamental alteration of metabolic rate has quick ramifications on the way body manages fat and instead of burning it, stores the same in the form of bad cholesterol.

China is now home to more polluted cities than anywhere in the world. No wonder, then, that the research was funded by several agencies of the Chinese government. To establish the harmful effect of pollution on the human body, researchers divided pregnant rats into one chamber, exposing them to highly polluted outdoor air that's commonly observed in Beijing. In the other chamber, the rest of the pregnant rats were exposed to air that had been relatively purified. The air these rats breathed was significantly devoid of air pollution particles, reported AJMC.

Within just 19 days, the pregnant rats exposed to polluted air showed dangerously high levels of inflammation in their lungs and livers. While this severe reaction to toxic air was expected, researchers observed that these rats also had 50 percent higher levels of "bad" LDL cholesterol, and 46 percent higher levels of triglycerides, which is a type of fat in blood that can increase the risk of heart disease.

Horrifyingly, the rats exposed to polluted air had 97 percent higher total cholesterol. The smog also forced the rats to have poorer responses to insulin. In other words, their bodies did not react adequately to insulin to keep their blood sugar in check. This condition is commonly observed in humans when they are on the brink of developing of Type 2 diabetes. Speaking about the research, Junfeng "Jim" Zhang, a professor of global and environmental health at Duke University and a senior author of the paper, said:
"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. 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."
What's even more concerning is that the negative effects of air pollution seem to be hereditary. When the pregnant rats gave birth, the offspring displayed the same negative effects. However, the baby rats were kept in the same chamber as their mothers, and hence the results might have been affected.

When the male and female rats were compared, the results were quite consistent. The female and male rats prenatally and postnatally exposed to air pollution were 10 percent and 18 percent heavier, respectively, at eight weeks than those exposed to clean air -- despite both groups being fed the same diet, reported The Daily Mail. This suggests that long-term exposure is needed to cause the continuous inflammation and metabolic dysfunction that leads to weight gain. Unfortunately, the researchers haven't checked if exposing these affected rats to clean air reversed the effect of pollution.

[Photo by Kevin Frayer/Getty Images]