Does air pollution make you obese?
Researchers at Ohio State University have researched the question if air pollution manes you obese. Their research has revealed, for the first time, that exposure to fine particulate matter (PM) air pollution causes inflammation and changes in fat cells that lead to obesity, often a precursor of diabetes. So breathing in polluted air loaded with PM might not only be an asthma cause bring about cardiovascular disease - it could be compromising your long-term health in other ways.
The researcher Qinghua Sun and his team fed mice either a normal diet or a high-fat diet. Then they exposed them to either filtered air, or to air containing a high level of PM for six hours a day, five days a week, for ten weeks to see what would happen. The polluted air in this experiment contained 111 micrograms of PMs which the researchers say is similar to the level found in many urban settings. The exposure time of the mice was equivalent to that you might expect for a toddler growing up to adolescence in an urban area. In that regard, the experiments are a good indicator of what exposure to outdoor or indoor air pollution might do to humans.
The mice on the high-fat diet gained more weight than those on the normal diet - as expected. But comparing the normal diet mice showed that those exposed to air pollution showed more signs of trouble, including higher blood sugar, had more abdominal fat, and more signs of inflammation - all compared to mice exposed to air that was filtered by an air purifier. Fat cells in abdominal fat are known to increase inflammation - which can set the scene for diabetes and heart disease.
'We really wanted to see how air pollution affects obesity with this early life exposure,' said Sun. 'In a real-world scenario, it would be very difficult to escape from the pervasive influence of dirty air, an influence that begins very early on in life.'
The researchers do not yet know if these effects would carry on over into adult life or, indeed, if they are reversible. Further experiments suggested that a gene called p47phox might be involved in translating the impact of PMs into increased abdominal fat. But the question remains if this research is really applicable to humans. Many scientists seem to think so, and we will find out more soon- because the same researchers are to carry out a study in Beijing, China, of the impact of PM air pollution on metabolic syndrome - a collection of risk factors leading to heart disease and diabetes.
According to the US Environmental Protection Agency, one in three people in the US is at a higher risk of experiencing health effects relating to the presence of air pollution. Because of the tiny size of urban air pollution - 2.5 micrometers or less in diameter (one-thirtieth of the width of a human hair) - PMs can reach deep into the lungs, blood, and cells, and thus reach every organ of the body.
Xu X et al Effect of Early Particulate Air Pollution Exposure on Obesity in Mice Arteriosclerosis, Thrombosis, and Vascular Biology December 2010;30:2518-2527