Pollution causes weight gain after just 19 days of exposure, finds new study that used Beijing air
Lab rats that breathed in the Chinese capital’s highly polluted air were heavier than rats that inhaled clean air after just three weeks of exposure, despite both groups being fed the same diet
Pollution could be disrupting your weight-loss plans: laboratory rats who breathed in Beijing’s highly polluted air gained weight and experienced cardiorespiratory and metabolic dysfunctions after only 19 days of exposure, finds a new study funded by various Chinese government agencies.
Researchers placed pregnant rats and their offspring in two chambers, one exposed to outdoor Beijing air and the other containing an air filter that removed most of the air pollution particles.
After only 19 days, the lungs and livers of pregnant rats exposed to the polluted air were heavier and showed increased tissue inflammation. These rats had 50 per cent higher low-density lipoprotein (LDL, or “bad”) cholesterol; 46 per cent higher triglycerides, a type of fat in the blood; and 97 per cent higher total cholesterol. Their insulin resistance level, a precursor of Type 2 diabetes, was higher than their clean air-breathing counterparts.
All these changes, known as metabolic dysfunctions, may lead to obesity.
“Since chronic inflammation is recognised 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,” says Junfeng Zhang, a professor of global and environmental health at Duke University in North Carolina, US, and a senior author of the paper.
The pollution-exposed rats were significantly heavier at the end of their pregnancy even though the rats in both groups were fed the same diet. Similar results were shown in the rat offspring, which were kept in the same chambers as their mothers.