Startling new research shows that pollution can make children fat. This is according to a recent Spanish study that indicates that children exposed to pesticide in the womb are twice as likely to be overweight.
At least 300 million people worldwide are obese. The main explanation is that they are consuming more calories than they burn. But there is growing evidence that diet and lack of exercise, though critical, cannot alone explain the rapid growth of the epidemic.
It has long been known that genetics give people different metabolisms, making some gain weight more easily than others. But the new study by scientists at Barcelona's Municipal Institute of Medical Research suggests that pollution may similarly predispose people to get fat.
The research measured levels of hexachlorobenzene (HCB), an internationally banned pesticide, in the umbilical cords of 403 children. It found that those with the highest levels were twice as likely to be obese when they reached the age of six and a half.
Experiments have shown that many chemicals fed to pregnant animals cause their offspring to grow up obese. These include organotins, long employed in antifouling paints on ships and now widely found in fish; bisphenol A (BPA), used in baby bottles and to line cans of food, among countless other applications; and phthalates, found in cosmetics, shampoos, plastics to wrap food, and in a host of other everyday products.
These pollutants – dubbed "obesogens" as a result of these findings – are so ubiquitous that almost everyone now has them in their bodies. Ninety-five per cent of Americans excrete BPA in their urine; 90 per cent of babies have been found to be exposed to phthalates in the womb; and every umbilical cord analysed in the new Spanish study was found to contain organchlorine pesticides such as HCB.
Still, no one knows how HCB causes obesity.