Air pollution is linked to weight gain, obesity and insulin resistance. Thanks to a new study, we now have yet another reason to hate it. The paper is published in FASEB Journal.
Though air pollution has pervaded almost all of our planet, Beijing, the capital of China, remains the most affected one by far. According to the World Health Organisation (WHO), its air can be containing pollutant particles in amounts exceeding the recommendations by over 10 times. Given that this is becoming a growing concern, scientists are frequently evaluating the effects thereof. Previous studies have suggested that heavier traffic (and thus pollution) is linked with higher body mass index (BMI, an indicator of obesity), and that mice babies were heavier if their mothers were exposed to exhaust fumes during pregnancy. The researchers of the new study have followed suit, and attempted to find out the influence of Beijing’s heavily polluted air on the health of pregnant rats.
Led by Jim Zhang from Duke University in Durham, the team, working in Beijing, placed two groups of rats in two different chambers, both fed with polluted air from the city, while the second one was equipped with a filter; the latter is said to have removed most of the big pollutants, and some of the smaller ones, rendering the air like that existing in cities of the US. Also, to ensure that no other variable affects the results, the rats were provided with the same type and amount of food.
The findings show that the pregnant rats from the polluted-air chamber weighed more than their counterparts after 19 days. Furthermore, the former had not only greater blood cholesterol levels but also considerably more inflammation and greater insulin resistance. The researchers concluded that these symptoms suggest the rats of the first group were going through metabolic syndrome, thereby putting them at risk to developing heart disease and diabetes.
Another phase of the study was studying the rats after they gave birth. The resulting babies were made to stay in the same chamber as their mothers. Yet again, we find that polluted air is linked with weight gain as the pups in the first chamber were heavier than the pups in the cleaner room; they also had more inflammation, and were insulin resistant like their parents.
The time spent in the chamber is also worth considering as Zhang says how the longer the pups breathed in polluted air, the more unhealthy they would become.
While the study does not show how pollution lead to metabolic problems, Zhang and his team have suggested that the processing of fat and sugar might be the pathways through which the complications arise. They add that the inflammation occurring in the lungs, blood, and fat might be responsible for the weight gain.
Zhang, therefore, recommends people to stay indoors on days when the pollution reaches higher levels.