Given the development of the world and our uses of synthetic materials, like plastic, it's not surprising that they have begun to affect our health. Recent research has uncovered the fact that BPA exposure can increase a young girl's risk of obesity later in life.

Bisphenol-A (BPA) is a chemical used to shape plastics into familiar shapes like water bottles, cups, and plates and to coat metal products like cans and pipes. While plastics are highly useful, past stuides have found that BPA exposure has been found to cause negative effects in the brain and digestive system.

And now a new study indicates that high levels of BPA can enter the blood stream via these everyday products and cause obesity in young girls. The study examined the levels of BPA in the urine of 1,326 students in grades 4 through 12. Results indicated that girls aged nine through 12 who were exposed to BPA had a five-fold risk of developing obesity, and 64 percent of those girls were overweight. Conversely, this trend was not seen among boys of any age, even with BPA exposure.

In order to test whether it was the BPA, instead of other factors, leading to obesity, researchers tested BPA levels and weight gain in mice. Again, they found that only female mice were affected and gained weight rapidly, while male mice were unaffected. This environmental "obesogen," or chemical that leads to obesity, has a clear effect on the health of young girls.

Obesity is best defined as having an excess amount of fat in one's body. Obesity causes many health issues like diabetes, heart disease, high blood pressure, and reduced lung function. These issues often make obesity a cause of death, as the excess fat allows for deterioration of bodily function. Obesity is caused by a number of things like inactivity, unhealthy diet, lack of sleep, and other medical problems that may slow metabolism, or the body's ability to burn energy in the form of fat.

"Girls in the midst of puberty may be more sensitive to the impacts of BPA on their energy balance and fat metabolism," said Dr. De-Kun Li, M.D., Ph.D., principal investigator of the study.

The researchers conjecture that BPA wreaks havoc on the younger girls' metabolic processes. BPA has been shown to block the burning of fat; obesity is most simply defined as a buildup of excess fat. They also have found that BPA acts on estrogen receptors. These receptors are female specific, as only women have the hormone estrogen and its corresponding receptor in their body. If the BPA does not have a receptor, or place to attach, in the body, as it wouldn't in men, it cannot have any effect.

The interaction of BPA at the estrogen receptor is also significant because in young girls, aged nine to 12, there is little estrogen in the body, as they have not quite reached puberty. If the BPA is stimulating the estrogen receptor at this early stage of sexual development, it can lead to weight gain that a girl's body cannot yet deal with, which may lead to obesity. The trend was not seen in girls older than 12, however, possibly because they had already entered puberty and their bodies could either disperse the weight or burn it off easily, since they had reached sexual maturity, and stimulation of their estrogen receptors is no longer problematic at that point.

While the Food and Drug Administration (FDA) has said BPA is safe at very low levels, the Mayo Clinic advises taking measures to prevent BPA exposure. These include seeking BPA-free products, using fewer canned foods, avoiding putting plastic dishes in the microwave or dishwasher, and using alternatives such as ceramic, glass, or metal containers.

Source: Li D, Miao M, Zhou Z, et al. Urine Bisphenol-A Level in Relation to Obesity and Overweight in School-Age Children. PLOS ONE. 2013.