BPA's real threat may be after it has metabolized: Chemical found in many plastics linked to multiple health threats

Bisphenol A or BPA is a synthetic chemical widely used in the making of plastic products ranging from bottles and food can linings to toys and water supply lines. When these plastics degrade, BPA is released into the environment and routinely ingested.

New research, however, from the University of California, San Diego School of Medicine suggests it is the metabolic changes that take place once BPA is broken down inside the body that pose the greater health threat.

More than 90 percent of all Americans are believed to carry varying levels of BPA exposure.
In recent years, numerous studies have reported alarming associations between BPA exposure and myriad adverse health and development effects, from cancer and neurological disorders to physiological defects and, perhaps, a cause of childhood obesity.

Of particular concern is that BPA exposure is correlated with disruption of estrogen signaling. The chemical's molecular structure is similar to that of estradiol, one of the human body's three main estrogens, suggesting that BPA binds to estrogen receptors. The estrogen receptor is designed to grab and hold estradiol and related estrogens. Disparate chemicals, however, can share some structures found in estrogens, enabling them to bind to the estrogen receptor. When that happens, problems can occur.